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Colour displays for categorical images
We propose a method for identifying a set of colours for displaying 2D and 3D categorical images when the categories are unordered labels. The principle is to find maximally distinct sets of colours. We either generate colours sequentially, to maximize the dissimilarity or distance between a new colour and the set of colours already chosen, or use a simulated annealing
Chris Glasbey; Heijden van der G. W. A. M; V. F. K. Toh; Alision Gray
Cadmium colours: composition and properties
NASA Astrophysics Data System (ADS)
The composition and the properties of cadmium aquarelle colours are discussed. The examined colours were 24 different aquarelle cadmium colours from six different manufacturers. The colours ranged from light, bright yellows to dark, deep-red tones. The aim of this research was to find out if the pigments contain cadmium salts: sulphides and/or selenides. This information will help in choosing watercolours in conservation processes. Today, aquarelle colours not containing cadmium pigments are being sold as cadmium colours; thus their properties might be different from actual cadmium colours. The aim of the research was to verify that the colour samples contained cadmium pigments and to estimate their compositions and ageing properties. Element analyses were performed from colour samples using micro-chemical tests and X-ray fluorescence measurements. Thin-layer chromatography was used for analysing gum Arabic as a possible binding medium in the chosen colour samples. Through ageing tests, the resistance of the colour samples to the exposure to light, heat and humidity was studied. Visible-light spectroscopy was used in determining the hues and hue changes of the aquarelle colour samples. The spectrophotometer used the CIE L*a*b* tone colour measuring system. From the colour measurements the changes in the lightness/darkness, the redness, the yellowness and the saturation of the samples were examined.
Paulus, J.; Knuutinen, U.
RGB-NDVI colour composites for visualizing forest change dynamics
A simple and logical technique was developed to display and quantify forest change using three dates of satellite imagery. The normalized difference vegetation index (NDVI) was computed for each date of imagery to define high and low vegetation biomass. Colour composites were generated by combining each date of NDVI with either the red, green, or blue (RGB) image planes in
Colour Interest Points for Image Retrieval
In image retrieval scenarios, many methods use interest point detection at an early stage to find regions in which descriptors are calculated. Finding salient locations in image data is crucial for these tasks. Observing that most current methods use only the luminance information of the images, we investigate the use of colour information in in- terest point detection. Based on
Nicu Sebe; Theo Gevers; Allan Hanbury
Dual-colour imaging with GFP variants
Green fluorescent protein (GFP) has become an important tool in cell biology and is widely used as a reporter for imaging intracellular proteins and structures in live cells. Recently, spectral variants of GFP with red- and blue-shifted fluorescence emissions have been characterized, opening the possibility of double labelling with two different-coloured GFP fusion proteins. This article reviews recent advances in
Jan Ellenberg; Jennifer Lippincott-Schwartz; John F. Presley
Colour appearance descriptors for image browsing and retrieval
NASA Astrophysics Data System (ADS)
In this paper, we focus on the development of whole-scene colour appearance descriptors for classification to be used in browsing applications. The descriptors can classify a whole-scene image into various categories of semantically-based colour appearance. Colour appearance is an important feature and has been extensively used in image-analysis, retrieval and classification. By using pre-existing global CIELAB colour histograms, firstly, we try to develop metrics for whole-scene colour appearance: "colour strength", "high/low lightness" and "multicoloured". Secondly we propose methods using these metrics either alone or combined to classify whole-scene images into five categories of appearance: strong, pastel, dark, pale and multicoloured. Experiments show positive results and that the global colour histogram is actually useful and can be used for whole-scene colour appearance classification. We have also conducted a small-scale human evaluation test on whole-scene colour appearance. The results show, with suitable threshold settings, the proposed methods can describe the whole-scene colour appearance of images close to human classification. The descriptors were tested on thousands of images from various scenes: paintings, natural scenes, objects, photographs and documents. The colour appearance classifications are being integrated into an image browsing system which allows them to also be used to refine browsing.
Othman, Aniza; Martinez, Kirk
Quantification of Japanese quail eggshell colour by image analysis.
The Japanese quail lays eggs with colourful and patterned shells which make the eggshell colour difficult to classify. In this study, the method of measuring colour of patchy eggs using image analyses and its power to discriminate among individual variation were established. Estimated repeatability for egg colour and proportion of patterned areas was high (>0.58), suggesting intermed�ate or high heritability of eggshell colour characteristics. Three components have been identified as significant in discriminant function analysis. These three components explained 91.4% of the total variance in egg colour characteristics. In cluster analysis, 78.3% of the eggs that were collected from 15 females were correctly classified. This study indicates that eggshell colour characteristics can be reliably studied by image analyses and that this method can provide a unified character list for future examinations and interpretations of quail egg characteristics. PMID:19621137
Sezer, Metin; Tekelioglu, Oguz
Efficient colour splitters for high-pixel-density image sensors
NASA Astrophysics Data System (ADS)
When the pixel size of image sensors shrinks to the wavelength of light, this results in low signal levels for a given photon flux per pixel as a result of scaling laws. Because many image sensors require colour filters, it becomes crucial for small-pixel sensors to have an efficient filtering method that can capture all incident photons without absorbing them. Here, we propose a new method to split colours by using a microscale plate-like structure with a transparent medium that has a higher refractive index than the surrounding material. We experimentally demonstrate that this principle of colour splitting based on near-field deflection can generate colour images with minimal signal loss. From comparisons of the sum of the total integrated values for the colour channels, we confirm the amount of light received is 1.85 times that of the conventional colour filter method of the Bayer array, while maintaining the same level of resolution.
Nishiwaki, Seiji; Nakamura, Tatsuya; Hiramoto, Masao; Fujii, Toshiya; Suzuki, Masa-Aki
Improved image retrieval based on fuzzy colour feature vector
NASA Astrophysics Data System (ADS)
One of Image indexing techniques is the Content-Based Image Retrieval which is an efficient way for retrieving images from the image database automatically based on their visual contents such as colour, texture, and shape. In this paper will be discuss how using content-based image retrieval (CBIR) method by colour feature extraction and similarity checking. By dividing the query image and all images in the database into pieces and extract the features of each part separately and comparing the corresponding portions in order to increase the accuracy in the retrieval. The proposed approach is based on the use of fuzzy sets, to overcome the problem of curse of dimensionality. The contribution of colour of each pixel is associated to all the bins in the histogram using fuzzy-set membership functions. As a result, the Fuzzy Colour Histogram (FCH), outperformed the Conventional Colour Histogram (CCH) in image retrieving, due to its speedy results, where were images represented as signatures that took less size of memory, depending on the number of divisions. The results also showed that FCH is less sensitive and more robust to brightness changes than the CCH with better retrieval recall values.
Ben-Ahmeida, Ahlam M.; Ben Sasi, Ahmed Y.
Variable-rate colour image quantization based on quadtree segmentation
NASA Astrophysics Data System (ADS)
A novel variable-sized block encoding with threshold control for colour image quantization (CIQ) is presented in this paper. In CIQ, the colour palette used has a great influence on the reconstructed image quality. Typically, a higher image quality and a larger storage cost are obtained when a larger-sized palette is used in CIQ. To cut down the storage cost while preserving quality of the reconstructed images, the threshold control policy for quadtree segmentation is used in this paper. Experimental results show that the proposed method adaptively provides desired bit rates while having better image qualities comparing to CIQ with the usage of multiple palettes of different sizes.
Hu, Y. C.; Li, C. Y.; Chuang, J. C.; Lo, C. C.
Ultra-realistic 3-D imaging based on colour holography
NASA Astrophysics Data System (ADS)
A review of recent progress in colour holography is provided with new applications. Colour holography recording techniques in silver-halide emulsions are discussed. Both analogue, mainly Denisyuk colour holograms, and digitally-printed colour holograms are described and their recent improvements. An alternative to silver-halide materials are the panchromatic photopolymer materials such as the DuPont and Bayer photopolymers which are covered. The light sources used to illuminate the recorded holograms are very important to obtain ultra-realistic 3-D images. In particular the new light sources based on RGB LEDs are described. They show improved image quality over today's commonly used halogen lights. Recent work in colour holography by holographers and companies in different countries around the world are included. To record and display ultra-realistic 3-D images with perfect colour rendering are highly dependent on the correct recording technique using the optimal recording laser wavelengths, the availability of improved panchromatic recording materials and combined with new display light sources.
Bjelkhagen, H. I.
Multispectral image invariant to illumination colour, strength, and shading
NASA Astrophysics Data System (ADS)
We present here a method that makes use of multispectral image data and generates a novel "photometric-invariant multispectral image" for this type of data. For RGB, an invariant image has been constructed independent of the colour and intensity of the illuminant and of shading. To generate this image either a set of calibration images is required, or entropy information taken from a single image can be used to develop the parameters necessary to produce the invariant. Nonetheless, generating an invariant image remains a complex and error-prone task for RGB image data. For multispectral images, we show that photometric-invariant image formation is in essence greatly simplified. One of the requirements for forming an invariant is the necessity of narrowband-sensor sensors. Here this is the case, and we show that with the simple knowledge of peak sensor wavelengths we can generate a high-D multispectral invariant. The PSNR is shown to be high between the respective invariant multispectral features for multispectral images taken under different illumination conditions, showing lighting invariance for a per-pixel measure; and the s-CIELAB error measure shows that the colour error between the 3-D colour images used to visualize the output invariant high-D data is also small.
Drew, Mark S.; Yazdani Salekdeh, Amin
Super-realistic-looking images based on colour holography and Lippmann photography
Two imaging techniques will be presented which can create remarkable images. The first technique is colour holography, which provides full parallax 3D colour images with a large field of view. The virtual colour image recorded in a holographic plate represents the most realistic-looking image of an object that can be obtained today. The extensive field of view adds to the
Hans I. Bjelkhagen
Colour coding of intensity levels in CCD images
NASA Astrophysics Data System (ADS)
Present methods of displaying electronic images from Charge Coupled Device (CCD) cameras often fall short of ideal. The production of hard copy from computer printers or by the photography of monitors frequently limits the quantity and quality of information available. One way to improve the transfer of information from electronic files to human eye and brain is to see a spectrum of colours in addition to the usual brightness variations. The addition of colour gives an added dimension to the images and enables subtle variations in intensity to be more readily perceived.
Neville, R. J.
Colour Doppler imaging of intracranial vasculopathy in severe infantile sialidosis
Neonatal ascites is usually attributed to prenatal infections, lysosomal storage disease and anomalies of the genitourinary tract, gastrointestinal tract or cardiovascular system. We report one case of neonatal ascites associated with infantile sialidosis. Cerebral sonography showed stripe-like intracerebral echogenicities in the region of the basal ganglia. Colour Doppler imaging demonstrated blood flow within the echogenicities confirming the suspected diagnosis of
M. Ries; K.-H. Deeg; D. W�lfel; H. Ibel; B. Maier; G. Buheitel
Liquid crystal thermography and true-colour digital image processing
In the last decade thermochromic liquid crystals (TLC) and true-colour digital image processing have been successfully used in non-intrusive technical, industrial and biomedical studies and applications. Thin coatings of TLCs at surfaces are utilized to obtain detailed temperature distributions and heat transfer rates for steady or transient processes. Liquid crystals also can be used to make visible the temperature and
J. Stasiek; A. Stasiek; M. Jewartowski; M. W. Collins
Colour Stability of Veneering Composites after Accelerated Aging
Objectives: To investigate the colour stability of four indirect composite restorative materials after accelerated aging. Methods: Four indirect composites (Gradia, Signum+, HFO and Adoro) were used. For each material, six specimens were prepared and subjected to accelerated aging (Suntest CPS+, Atlas, Chicago, IL, USA) according to ISO 7491. A Dr. Lange Microcolor Data Station colorimeter (Braive Instruments, Liege, Belgium) was used to measure specimen colour before and after aging. Measurements were performed according to the CIE L*a*b* system, and the mean L*, a* and b* values for each material were calculated. The equation ?E = [(?L*)2 + (?a*)2 + (?b*)2]1/2 was used to measure the total colour change (?E), where ?L*, ?a* and ?b* are the differences in the respective values before and after aging. One-way ANOVA were used to determine statistically significant differences in ?L*, ?a*, ?b* and ?E. Results: No statistically significant differences were found in ?L*, ?a*, ?b* and ?E among the materials tested (P?L*=.063; P?a*=.521; P?b*=.984 and P?E=.408). After aging, Gradia specimens showed an increase in lightness (?L*=0.36) and a green-yellow shift (?a*=?1.18, ?b*=0.6), while Signum+ specimens exhibited an increase in lightness (?L*=0.5) and a green-blue shift (?a*=?0.9, ?b*=?0.45). HFO specimens exhibited an increase in lightness (?L*=0.75) and a green-yellow shift (?a*=?1.3, ?b*=0.06), and Adoro specimens exhibited an increase in lightness (?L*=2.07) and a green-yellow shift (?a*=?1.3, ?b*=0.68). Conclusions: Colour changes were found to be within accepted values of perceptibility and clinical acceptance after accelerated aging, and no statistically significant differences were found in ?L*, ?a*, ?b* and ?E among the materials tested.
Papadopoulos, Triantafillos; Sarafianou, Aspasia; Hatzikyriakos, Andreas
Colour Doppler imaging in the demonstration of an orbital varix.
Colour Doppler imaging (CDI) is a recent development in ultrasonography. It allows simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow. Quantitative information on flow velocity is obtained by pulsed Doppler spectral analysis, the colour information being used to choose the vessel of interest. Using this technique the authors examined a patient with an orbital varix previously diagnosed by clinical findings and computed tomography. Dynamic evaluation with real-time direct imaging of flow facilitated the diagnosis of this orbital disorder without the need for any contrast material. This technique may prove to be a useful adjunct to computed tomography for the evaluation of suspected vascular lesions of the orbit. Images
Lieb, W. E.; Merton, D. A.; Shields, J. A.; Cohen, S. M.; Mitchell, D. D.; Goldberg, B. B.
Deepest Wide-Field Colour Image in the Southern Sky
NASA Astrophysics Data System (ADS)
LA SILLA CAMERA OBSERVES CHANDRA DEEP FIELD SOUTH ESO PR Photo 02a/03 ESO PR Photo 02a/03 [Preview - JPEG: 400 x 437 pix - 95k] [Normal - JPEG: 800 x 873 pix - 904k] [HiRes - JPEG: 4000 x 4366 pix - 23.1M] Caption : PR Photo 02a/03 shows a three-colour composite image of the Chandra Deep Field South (CDF-S) , obtained with the Wide Field Imager (WFI) camera on the 2.2-m MPG/ESO telescope at the ESO La Silla Observatory (Chile). It was produced by the combination of about 450 images with a total exposure time of nearly 50 hours. The field measures 36 x 34 arcmin 2 ; North is up and East is left. Technical information is available below. The combined efforts of three European teams of astronomers, targeting the same sky field in the southern constellation Fornax (The Oven) have enabled them to construct a very deep, true-colour image - opening an exceptionally clear view towards the distant universe . The image ( PR Photo 02a/03 ) covers an area somewhat larger than the full moon. It displays more than 100,000 galaxies, several thousand stars and hundreds of quasars. It is based on images with a total exposure time of nearly 50 hours, collected under good observing conditions with the Wide Field Imager (WFI) on the MPG/ESO 2.2m telescope at the ESO La Silla Observatory (Chile) - many of them extracted from the ESO Science Data Archive . The position of this southern sky field was chosen by Riccardo Giacconi (Nobel Laureate in Physics 2002) at a time when he was Director General of ESO, together with Piero Rosati (ESO). It was selected as a sky region towards which the NASA Chandra X-ray satellite observatory , launched in July 1999, would be pointed while carrying out a very long exposure (lasting a total of 1 million seconds, or 278 hours) in order to detect the faintest possible X-ray sources. The field is now known as the Chandra Deep Field South (CDF-S) . The new WFI photo of CDF-S does not reach quite as deep as the available images of the "Hubble Deep Fields" (HDF-N in the northern and HDF-S in the southern sky, cf. e.g. ESO PR Photo 35a/98 ), but the field-of-view is about 200 times larger. The present image displays about 50 times more galaxies than the HDF images, and therefore provides a more representative view of the universe . The WFI CDF-S image will now form a most useful basis for the very extensive and systematic census of the population of distant galaxies and quasars, allowing at once a detailed study of all evolutionary stages of the universe since it was about 2 billion years old . These investigations have started and are expected to provide information about the evolution of galaxies in unprecedented detail. They will offer insights into the history of star formation and how the internal structure of galaxies changes with time and, not least, throw light on how these two evolutionary aspects are interconnected. GALAXIES IN THE WFI IMAGE ESO PR Photo 02b/03 ESO PR Photo 02b/03 [Preview - JPEG: 488 x 400 pix - 112k] [Normal - JPEG: 896 x 800 pix - 1.0M] [Full-Res - JPEG: 2591 x 2313 pix - 8.6M] Caption : PR Photo 02b/03 contains a collection of twelve subfields from the full WFI Chandra Deep Field South (WFI CDF-S), centred on (pairs or groups of) galaxies. Each of the subfields measures 2.5 x 2.5 arcmin 2 (635 x 658 pix 2 ; 1 pixel = 0.238 arcsec). North is up and East is left. Technical information is available below. The WFI CDF-S colour image - of which the full field is shown in PR Photo 02a/03 - was constructed from all available observations in the optical B- ,V- and R-bands obtained under good conditions with the Wide Field Imager (WFI) on the 2.2-m MPG/ESO telescope at the ESO La Silla Observatory (Chile), and now stored in the ESO Science Data Archive. It is the "deepest" image ever taken with this instrument. It covers a sky field measuring 36 x 34 arcmin 2 , i.e., an area somewhat larger than that of the full moon. The observations were collected during a period of nearly four years, beginning in January 1999 when the WFI instrument was first installed (cf. ESO PR 02/99
KM and KHM Clustering Techniques for Colour Image Quantisation
\\u000a This paper deals with the comparison of two clustering techniques kmeans (KM) and k-harmonic means (KHM) in the case of their use in colour image quantisation. The classical KMtechnique establishes good background for this comparison. Authors proposed two original heuristic initialisation methods,\\u000a one arbitrary(DC) and one adaptive (SD), that were used in both techniques. Apart from specific validity indices for
Mariusz Frackiewicz; Henryk Palus
A colour scheme for the display of astronomical intensity images
NASA Astrophysics Data System (ADS)
I describe a colour scheme that is appropriate for the screen display of intensity images. This -- unlike many currently available schemes -- is designed to be monotonically increasing in terms of its perceived brightness. Also, when printed on a black and white postscript printer, the scheme results in a greyscale with monotonically increasing brightness. This scheme has recently been incorporated into the radio astronomical analysis packages CASA and AIPS.
Green, D. A.
Applying colour science in colour design
NASA Astrophysics Data System (ADS)
Although colour science has been widely used in a variety of industries over the years, it has not been fully explored in the field of product design. This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling. By integrating these advanced colour technologies together with modern colour imaging devices such as display, camera, scanner and printer, some computer systems have been recently developed to assist designers for designing colour palettes through colour selection by means of a number of widely used colour order systems, for creating harmonised colour schemes via a categorical colour system, for generating emotion colours using various colour emotional scales and for facilitating colour naming via a colour-name library. All systems are also capable of providing accurate colour representation on displays and output to different imaging devices such as printers.
Luo, Ming Ronnier
Spectral imaging system for non-contact colour measurement
NASA Astrophysics Data System (ADS)
This paper describes the development of a non-contact system for measuring colour of printed material at web speeds. The system proposed uses a non-contact spectrophotometer based on a holographic grating, in conjunction with a conventional monochrome area scan camera, from which colour spectral data is extracted, whilst a xenon flash is used to illuminate colour samples. Software and hardware details of the system are given, along with the underlying mathematics for colour space conversion and measurement. Conversion equations from X, Y, Z chromaticity co-ordinates to the RGB system are presented, and also equations to convert from the L ?a ?b ? colour space to X, Y, Z chromaticity co-ordinates. Experimental results are presented whereby the non-contact spectral system is shown to perform to a colour tolerance exceeding that of conventional colour video systems.
Brown, N.; Peng, J.; Jackson, M. R.; Parkin, R. M.
RGB-NDVI colour composites for visualizing forest change dynamics
NASA Technical Reports Server (NTRS)
The study presents a simple and logical technique to display and quantify forest change using three dates of satellite imagery. The normalized difference vegetation index (NDVI) was computed for each date of imagery to define high and low vegetation biomass. Color composites were generated by combining each date of NDVI with either the red, green, or blue (RGB) image planes in an image display monitor. Harvest and regeneration areas were quantified by applying a modified parallelepiped classification creating an RGB-NDVI image with 27 classes that were grouped into nine major forest change categories. Aerial photographs and stand history maps are compared with the forest changes indicated by the RGB-NDVI image. The utility of the RGB-NDVI technique for supporting forest inventories and updating forest resource information systems are presented and discussed.
Sader, S. A.; Winne, J. C.
Composition of pigments and colour changes in green table olives related to processing type.
Brownish colourations in Natural green table olives (non-treated with alkali) make this product less attractive to consumers than Spanish-style green table olives (treated with alkali), which develop a more appreciated bright golden-yellow colour. These colour differences were studied in relation to changes in the composition of chlorophyll and carotenoid pigments, as well as polyphenolic compounds and polyphenol oxidase enzyme (PPO) activity. Natural green olives showed a different chlorophyll profile than Spanish-style. However, all the chlorophyll pigments formed in both processing types were Mg-free derivatives (mostly pheophytins) with similar colourations, ranging from grey to green brownish. In the carotenoid fraction no appreciable differences were found between both processing types. The fruit's brownish colour was mainly due to polymeric substances with a size of >1000 daltons and polyphenolic nature, resulting from an enzymatic oxidation by PPO of the o-diphenolic compounds present in the fresh fruits. PMID:25053036
Ram�rez, Eva; Gandul-Rojas, Beatriz; Romero, Concepci�n; Brenes, Manuel; Gallardo-Guerrero, Lourdes
Hybridization of colour information with texture by using mutual information for the classification of satellite images
In this article a construction of hybrid colour space from a set of classic colours spaces by using the algorithm MRMR is proposed. This algorithm is based on the mutual information. Our approach is evaluated on SPOT HRV (XS) image representing two forest areas in the region of Rabat. Feature extraction is done by the cooccurrence matrix. The SVM (Support
Hassan EI Maia; A. Hammouch; D. Aboutajdine
Analysis of the ignition process using a digital image and colour processing technique
NASA Astrophysics Data System (ADS)
An experimental investigation of flame emission properties in the ignition-to-flame propagation process has been conducted. In particular, the phenomenon of ignition delay was analysed through digital image processing and colour analysis. This processing methodology makes use of the observed correlation between a digital colour signal and physical flame emission characteristics in the visible spectrum. Aspects of red, green, blue and hue, saturation, value colour modelling principles were combined to turn a high-speed digital colour camera into an abstract multi-spectral system. Experiments were carried out on both a laboratory-based atmospheric burner and an industrial gas-turbine combustor. In both cases, results have shown that the commonly observed flame colour feature from the soot radiation does not signify the start of combustion reaction but rather a later stage of flame development. Additional weak colour quantities were identified via digital colour image processing in the ignition delay time interval where there were no previous definitive signals to designate the presence of combustion. This colour entity was found to match with the typical digital colour signal output from the stimulation of CH* and C2* radical chemiluminescence emissions.
Huang, Hua Wei; Zhang, Yang
Hundred metre virtual telescope captures unique detailed colour image
NASA Astrophysics Data System (ADS)
A team of French astronomers has captured one of the sharpest colour images ever made. They observed the star T Leporis, which appears, on the sky, as small as a two-storey house on the Moon [1]. The image was taken with ESO's Very Large Telescope Interferometer (VLTI), emulating a virtual telescope about 100 metres across and reveals a spherical molecular shell around an aged star. ESO PR Photo 06a/09 The star T Leporis as seen with VLTI ESO PR Photo 06b/09 The star T Leporis to scale ESO PR Photo 06c/09 A virtual 100-metre telescope ESO PR Photo 06d/09 The orbit of Theta1 Orionis C ESO PR Video 06a/09 Zoom-in onto T Leporis "This is one of the first images made using near-infrared interferometry," says lead author Jean-Baptiste Le Bouquin. Interferometry is a technique that combines the light from several telescopes, resulting in a vision as sharp as that of a giant telescope with a diameter equal to the largest separation between the telescopes used. Achieving this requires the VLTI system components to be positioned to an accuracy of a fraction of a micrometre over about 100 metres and maintained so throughout the observations -- a formidable technical challenge. When doing interferometry, astronomers must often content themselves with fringes, the characteristic pattern of dark and bright lines produced when two beams of light combine, from which they can model the physical properties of the object studied. But, if an object is observed on several runs with different combinations and configurations of telescopes, it is possible to put these results together to reconstruct an image of the object. This is what has now been done with ESO's VLTI, using the 1.8-metre Auxiliary Telescopes. "We were able to construct an amazing image, and reveal the onion-like structure of the atmosphere of a giant star at a late stage of its life for the first time," says Antoine M�rand, member of the team. "Numerical models and indirect data have allowed us to imagine the appearance of the star before, but it is quite astounding that we can now see it, and in colour." Although it is only 15 by 15 pixel across, the reconstructed image shows an extreme close-up of a star 100 times larger than the Sun, a diameter corresponding roughly to the distance between the Earth and the Sun. This star is, in turn, surrounded by a sphere of molecular gas, which is about three times as large again. T Leporis, in the constellation of Lepus (the Hare), is located 500 light-years away. It belongs to the family of Mira stars, well known to amateur astronomers. These are giant variable stars that have almost extinguished their nuclear fuel and are losing mass. They are nearing the end of their lives as stars, and will soon die, becoming white dwarfs. The Sun will become a Mira star in a few billion years, engulfing the Earth in the dust and gas expelled in its final throes. Mira stars are among the biggest factories of molecules and dust in the Universe, and T Leporis is no exception. It pulsates with a period of 380 days and loses the equivalent of the Earth's mass every year. Since the molecules and dust are formed in the layers of atmosphere surrounding the central star, astronomers would like to be able to see these layers. But this is no easy task, given that the stars themselves are so far away -- despite their huge intrinsic size, their apparent radius on the sky can be just half a millionth that of the Sun. "T Leporis looks so small from the Earth that only an interferometric facility, such as the VLTI at Paranal, can take an image of it. VLTI can resolve stars 15 times smaller than those resolved by the Hubble Space Telescope," says Le Bouquin. To create this image with the VLTI astronomers had to observe the star for several consecutive nights, using all the four movable 1.8-metre VLT Auxiliary Telescopes (ATs). The ATs were combined in different groups of three, and were also moved to different positions, creating more new interferometric configurations, so that astronomers could emulate a virtual telescope
An inverse method for the recovery of tissue parameters from colour images.
The interpretation of colour images is presented as an inverse problem in which a mapping is sought between image colour vectors and the physiological parameters characterizing a tissue. To ensure the necessary one-to-one correspondence between the image colours and the parameters, the mapping must be unique. This can be established through testing the sign of the determinant of the Jacobian matrix, a multi-dimensional equivalent of a discrete derivative, over the space of all parameter values. Furthermore, an optimisation procedure is employed to find the set of filters for image capture which generate image vectors minimizing the mapping error. This methodology applied to interpretation of skin images shows that the standard RGB system of filters provides for a unique mapping between image values and parameters characterizing the normal skin. It is further shown that an optimal set of filters reduces the error of quantification by a factor of 2, on average. PMID:15344467
Claridge, Ela; Preece, Steve J
The quaternion representation of colour is shown to be effective in the context of colour texture region segmentation in digital colour images. The advantage of using quaternion arithmetic is that a colour can be represented and analyzed as a single entity. A basis for the colour textures occurring in a given image is derived via quaternion principal component analysis of
Lilong Shi; Brian Funt
White-light full-field OCT resolution improvement by image sensor colour balance adjustment: numerical simulation
NASA Astrophysics Data System (ADS)
The possibility of improving white-light full-field optical coherence tomography (OCT) resolution by image sensor colour balance tuning is shown numerically. We calculated the full-width at half-maximum (FWHM) of a coherence pulse registered by a silicon colour image sensor under various colour balance settings. The calculations were made for both a halogen lamp and white LED sources. The results show that the interference pulse width can be reduced by the proper choice of colour balance coefficients. The reduction is up to 18%, as compared with a colour image sensor with regular settings, and up to 20%, as compared with a monochrome sensor.
Kalyanov, A. L.; Lychagov, V. V.; Ryabukho, V. P.; Smirnov, I. V.
Flame colour characterization in the visible and infrared spectrum using a digital camera and image processing
NASA Astrophysics Data System (ADS)
An attempt has been made to characterize the colour spectrum of methane flame under various burning conditions using RGB and HSV colour models instead of resolving the real physical spectrum. The results demonstrate that each type of flame has its own characteristic distribution in both the RGB and HSV space. It has also been observed that the averaged B and G values in the RGB model represent well the CH* and C*2 emission of methane premixed flame. Theses features may be utilized for flame measurement and monitoring. The great advantage of using a conventional camera for monitoring flame properties based on the colour spectrum is that it is readily available, easy to interface with a computer, cost effective and has certain spatial resolution. Furthermore, it has been demonstrated that a conventional digital camera is able to image flame not only in the visible spectrum but also in the infrared. This feature is useful in avoiding the problem of image saturation typically encountered in capturing the very bright sooty flames. As a result, further digital imaging processing and quantitative information extraction is possible. It has been identified that an infrared image also has its own distribution in both the RGB and HSV colour space in comparison with a flame image in the visible spectrum.
Huang, Hua-Wei; Zhang, Yang
Developments in the recovery of colour in fine art prints using spatial image processing
NASA Astrophysics Data System (ADS)
Printmakers have at their disposal a wide range of colour printing processes. The majority of artists will utilise high quality materials with the expectation that the best materials and pigments will ensure image permanence. However, as many artists have experienced, this is not always the case. Inks, papers and materials can deteriorate over time. For artists and conservators who need to restore colour or tone to a print could benefit from the assistance of spatial colour enhancement tools. This paper studies two collections from the same edition of fine art prints that were made in 1991. The first edition has been kept in an archive and not exposed to light. The second edition has been framed and exposed to light for about 18 years. Previous experiments using colour enhancement methods [9,10] have involved a series of photographs that had been taken under poor or extreme lighting conditions, fine art works, scanned works. There are a range of colour enhancement methods: Retinex, RSR, ACE, Histogram Equalisation, Auto Levels, which are described in this paper. In this paper we will concentrate on the ACE algorithm and use a range of parameters to process the printed images and describe these results.
Rizzi, A.; Parraman, C.
Optical coherence tomography, frequency-doubling technology, and colour Doppler imaging in ocular hypertension
PurposeTo study in ocular hypertension (OH) the retinal nerve fibre layer (RNFL) with optical coherence tomography (OCT) and the neuronal function with frequency-doubling technology (FDT) to assess which of the two methods was more sensitive in detecting early glaucomatous damage. Furthermore, a colour Doppler imaging (CDI) of the optic nerve was carried out to highlight any correlation with RNFL thickness
M Cellini; B Bernabini; M Carbonelli; E Zamparini; E C Campos
Developments in the recovery of colour in fine art prints using spatial image processing
Printmakers have at their disposal a wide range of colour printing processes. The majority of artists will utilise high quality materials with the expectation that the best materials and pigments will ensure image permanence. However, as many artists have experienced, this is not always the case. Inks, papers and materials can deteriorate over time. For artists and conservators who need
A. Rizzi; C. Parraman
Thermochromic liquid crystals and true colour image processing in heat transfer and fluid-flow research
In the last five years or so, true-colour image processing has gone being available mainly to highly technical users on expensive\\u000a image processing systems to being used by virtually anyone who can use a desktop computer. Also, during the past 25 years,\\u000a liquid crystals have emerged as reliable temperature sensors for heat transfer research, and have been applied in a
Jan Stasiek
Digital colour image processing based measurement of premixed CH 4 + air and C 2H 4 + air flame chemiluminescence
The experimental investigation of flame properties based on digital colour analysis has been conducted. In particular, the practicality of obtaining physical flame chemiluminescence characteristics through the inherent colour-filtering architecture employed in the digitisation of flame images was demonstrated. This is important as radical emission signals is an effective non-intrusive tool for deriving a number of useful combustion properties. In this
Hua Wei Huang; Yang Zhang
Modelling, calibration and rendition of colour logarithmic CMOS image sensors
Logarithmic CMOS image sensors encode a high dynamic range scene in a manner that roughly approximates human perception whereas linear sensors with equivalent quantisation suffer from saturation or loss of detail. Moreover, the continuous response of logarithmic pixels permit high frame rates and random access, features that are useful in motion detection. This paper describes how to model, calibrate and
Dileepan Joseph; Steve Collins
Robust optic disk segmentation from colour retinal images
We present a novel segmentation method to better capture the boundary of a non-homogeneous object such as the optic disk(OD), defined locally by two similar characteristic regions. Existing active contour models which utilise gradient information [12] or global region intensity [2] fail to localise aforementioned boundaries. We propose a region-based active contour model that uses local image information around each
Gopal Datt Joshi; Rohit Gautam; Jayanthi Sivaswamy; S. R. Krishnadas
Minimally invasive use of coloured composite resin in aesthetic restoration of periodontially involved teeth: Case report
Gingival recession causes not only aesthetic problems, but problems with oral hygiene, plaque accumulation, speech, and tooth sensitivity. Replacing the missing gingival tissue with composite resin, when indicated, can be a time- and cost-effective solution. Here we report the case of a 25-year-old female who presented with generalized gingival recession. Black triangles were present between the maxillary and mandibular anterior teeth due to loss of interdental tissues, caused by recent periodontal surgery. She also had slightly malposed maxillary anterior teeth. The patient elected to replace gingival tissue with pink composite resin and to alter the midline with composite resin veneers. The first treatment phase involved placement of pink gingival composite to restore the appearance of interdental papilla to her upper (16, 15, 14, 13, 12, 11, 21, 22, 23, and 24) and lower (34, 33, 32, 31, 41, 42, 43, and 44) teeth. Phase two was to place direct composite resin bonded veneers on her upper (16, 15, 14, 13, 12, 11, 21, 22, 23, and 24) teeth to alter the midline and achieve desired colour. The third treatment phase was to level the lower incisal edge shape by enameloplasty (31, 32, 41, and 42) to produce a more youthful and attractive smile. This case report and brief review attempt to describe the clinical obstacles and the current treatment options along with a suggested protocol. Use of contemporary materials such as gingival coloured composite to restore lost gingival tissue and improve aesthetics can be a simple and cost-effective way to manage patients affected by generalized aggressive periodontitis (AgP).
Wahbi, M.A.; Al Sharief, H.S.; Tayeb, H.; Bokhari, A.
The position and topography of the human colour centre as revealed by functional magnetic resonance imaging.
We used a colour Mondrian--an abstract scene with no recognizable objects--and its achromatic version to image the change in blood oxygenation in the brains of 12 human subjects, with the aim of learning more about the position and variability of the colour centre in the human brain. The results showed a consistent association of colour stimulation with activation of an area that is distinct from the primary visual areas, and lies in the ventral occipitotemporal cortex; we refer to it as human V4. The position of human V4, as defined on functional grounds, varies between individuals in absolute terms but is invariably found on the lateral aspect of the collateral sulcus on the fusiform gyrus. There was no indication of lingual gyral activation. In further studies designed to reveal the topographic map within V4, we stimulated the superior and inferior visual fields separately, using the same stimuli. We found that human V4 contains a representation of both the superior and inferior visual fields. In addition, there appears to be retinotopic organization of V4 with the superior visual field being represented more medially on the fusiform gyrus and the inferior field more laterally, the two areas abutting on one another. We find no evidence that suggests the existence of a separate representation of the inferior hemifield for colour in more dorsolateral regions of the occipital lobe. PMID:9448578
McKeefry, D J; Zeki, S
Composite imaging method for histological image analysis.
A composite imaging method has been developed that enables the user to directly capture a composite image by one-image capturing. It was experimentally verified that the composite images of bright-field, dark-field, and phase-contrast images can be captured with an arbitrary composition ratio. The difference in pixel values between the captured composite image and the computer composite image was small. This imaging method is realized only by placing below the condenser a masking plate, which can easily be made using Neutral Density filters. Therefore, little additional time and cost are needed. The composite imaging method was applied for extracting Helicobacter pylori in microscopic images of HE-stained gastric histological sections. H pylori is difficult to extract because the colors in H pylori are similar to those in other areas. It is experimentally shown that a composite image of phase-contrast and dark-field images captured using the proposed method improves the accuracy for extracting H pylori. PMID:24110455
Imai, Mizuho; Takei, Akane; Miyamoto, Keita; Takahashi, Masanobu; Nakano, Masayuki
UV durable colour pigment doped SmA liquid crystal composites for outdoor trans-reflective bi-stable displays
NASA Astrophysics Data System (ADS)
High brightness trans-reflective bi-stable displays based on smectic A (SmA) liquid crystals (LCs) can have nearly perfect transparency in the clear state and very high reflection in the scattered state. Because the LC material in use is stable under UV radiation, this kind of displays can stand for strong day-light and therefore be ideal for outdoor applications from e-books to public signage and advertisement. However, the colour application has been limited because the traditional colourants in use are conventional dyes which are lack of UV stability and that their colours are easily photo bleached. Here we present a colour SmA display demonstrator using pigments as colourant. Mixing pigments with SmA LCs and maintain the desirable optical switching performance is not straightforward. We show here how it can be done, including how to obtain fine sized pigment nano-particles, the effects of particle size and size distribution on the display performance. Our optimized pigments/SmA compositions can be driven by a low frequency waveform (~101Hz) to a scattered state to exhibit colour while by a high frequency waveform (~103Hz) to a cleared state showing no colour. Finally, we will present its excellent UV life-time (at least <7.2 years) in comparison with that of dye composition (~2.4 years). The complex interaction of pigment nano-particles with LC molecules and the resulting effects on the LC electro-optical performances are still to be fully understood. We hope this work will not only demonstrate a new and practical approach for outdoor reflective colour displays but also provide a new material system for fundamental liquid crystal colloid research work.
Xu, H.; Davey, A. B.; Crossland, W. A.; Chu, D. P.
A combined colour-infrared imaging technique for measuring water surface over non-horizontal bottom
NASA Astrophysics Data System (ADS)
This paper presents a combined colour-infrared imaging technique based on light refraction and absorption for measuring water surface over a non-horizontal fixed bottom known a priori. The procedure requires processing simultaneous visible and near-infrared digital images: on the one hand, the apparent displacement of a suitable pattern between reference and modulated visible images allows to evaluate the refraction effect induced by the water surface; on the other hand, near-infrared images allow to perform an accurate estimate of the penetration depth, due to the high absorption capacity of water in the near-infrared spectral range. The imaging technique is applied to a series of laboratory tests in order to estimate overall measurement accuracy. The results prove that the proposed method is robust and accurate and can be considered an effective non-intrusive tool for collecting spatially distributed experimental data.
Aureli, Francesca; Dazzi, Susanna; Maranzoni, Andrea; Mignosa, Paolo
Capsule endoscopy image analysis using texture information from various colour models.
Wireless capsule endoscopy (WCE) is a novel imaging technique that is gradually gaining ground as it enables the non-invasive and efficacious visualization of the digestive track, and especially the entire small bowel including its middle part. However, the task of reviewing the vast amount of images produced by a WCE examination is a burden for the physicians. To tackle this major drawback, an innovative scheme for discriminating endoscopic images related to one of the most common intestinal diseases, ulceration, is presented here. This new approach focuses on colour-texture features in order to investigate how the structure information of healthy and abnormal tissue is distributed on RGB, HSV and CIE Lab colour spaces. The WCE images are pre-processed using bidimensional ensemble empirical mode decomposition so as to facilitate differential lacunarity analysis to extract the texture patterns of normal and ulcerous regions. Experimental results demonstrated promising classification performance (mean accuracy>95%), exhibiting a high potential towards automatic WCE image analysis. PMID:22056811
Charisis, Vasileios S; Hadjileontiadis, Leontios J; Liatsos, Christos N; Mavrogiannis, Christos C; Sergiadis, George D
The value of colour Doppler imaging in assessing flow through ventriculo-peritoneal shunts.
So far, Doppler ultrasonography has had little application in paediatric neurosurgery. The incidental observation of normally invisible CSF flow from the peritoneal end of a ventriculo-peritoneal (V-P) shunt on colour Doppler during a conventional abdominal ultrasound examination in one of our patients suggested that colour Doppler imaging might be of potential interest. Using a 10-5 MHz broad-band linear array transducer, conventional 2D and Doppler (spectral and colour-coded) ultrasonography was performed in 17 patients with V-P shunts, who were aged 3 months to 12 years. In all, 20 examinations were performed, because 2 patients had repeat examinations before and after shunt revision. In 13 examinations (65%) CSF flow was identified through the shunt tube. Flow velocities between 5 and 7 cm/s were measured. No flow was seen in 7 examinations (35%), 3 of which (15%) were performed before revisions for a blocked shunt. Further in vitro studies with simulated shunt/ventricular system model demonstrated that although clear CSF is not ultrasonically visible, the presence of particulate matter, such as choroid plexus debris, can generate a satisfactory Doppler signal with the probe insonating over the length of the tubing. In the presence of clear CSF, turbulence generated at junction points of the shunt system or at the exit of the peritoneal tube can be visualised well with Doppler ultrasonography, presumably due to generation of microbubbles. The clinical implications for the management of shunt obstruction are discussed. PMID:8891363
Sgouros, S; John, P; Walsh, A R; Hockley, A D
Ontology-based lymphocyte population description using mathematical morphology on colour blood images.
Despite modern technologies (immunophenotyping, molecular probing, etc.) cytomorphologic examination of stained peripheral blood smears by microscopy remains the main way of diagnosis in a large variety of diseases (e.g. leukaemic disorders). Using tools from mathematical morphology for processing peripheral blood colour images, we have developed an image-based approach, to provide an objective and understandable description of lymphocyte populations according to a specifically designed ontology. This ontology-based framework needs a conceptualisation of the problem from a morphological viewpoint, the introduction of an adapted language, the generation of representative image databases, the development of image processing and data classification algorithms to automate the procedure and the validation of the system by human expertise. In this paper we present the main concepts, algorithms and some results to illustrate the high-performance of the approach. The aim of our work is to reconcile the automatisation with the medical expertise, so that they can reinforce each other. PMID:17543204
Angulo, J; Klossa, J; Flandrin, G
Distribution of colour-selective activity in the monkey inferior temporal cortex revealed by functional magnetic resonance imaging.
Previous electrophysiological, neuroimaging and lesion studies have suggested that the anterior part of the monkey inferior temporal (IT) cortex, or area TE, plays an important role in colour processing. However, little is known about how colour information is distributed in these cortical regions. Here, we explored the distribution of colour-selective activity in alert macaque monkeys using functional magnetic resonance imaging (fMRI) with two types of stimuli: a multicoloured ('Mondrian') pattern and an isoluminant colour grating. These two types of stimuli are both commonly used in human fMRI studies, but Mondrian stimuli, which contain a richer variety of hues and hence might be more suitable for activating higher-order areas than grating stimuli, have not been used to examine colour-selectivity in higher-order areas in earlier monkey studies. With the Mondrian stimuli, we observed that areas along the ventral pathway, V1, V2/V3, V4 and the IT cortex, responded more strongly to colour stimuli than to luminance stimuli. In the IT cortex, we found that colour-selective activities are not distributed uniformly, but are localized in discrete regions, each extending several millimetres in the anterior or posterior part of the IT cortex. The colour-selective activation in the anterior IT was observed only with the Mondrian stimuli, whereas the colour-selective activation in the posterior IT was observed with both the Mondrian and grating stimuli, with little overlap. These findings suggest that there are multiple subregions with differing stimulus selectivities distributed in the IT cortex, and that colour information is processed in these discrete subregions. PMID:19912328
Harada, Takuya; Goda, Naokazu; Ogawa, Tadashi; Ito, Minami; Toyoda, Hiroshi; Sadato, Norihiro; Komatsu, Hidehiko
Field programmable gate array based hardware implementation of a gradient filter for edge detection in colour images with subpixel precision
NASA Astrophysics Data System (ADS)
Within the field of industrial image processing the use of colour cameras becomes ever more common. Increasingly the established black and white cameras are replaced by economical single-chip colour cameras with Bayer pattern. The use of the additional colour information is particularly important for recognition or inspection. Become interesting however also for the geometric metrology, if measuring tasks can be solved more robust or more exactly. However only few suitable algorithms are available, in order to detect edges with the necessary precision. All attempts require however additional computation expenditure. On the basis of a new filter for edge detection in colour images with subpixel precision, the implementation on a pre-processing hardware platform is presented. Hardware implemented filters offer the advantage that they can be used easily with existing measuring software, since after the filtering a single channel image is present, which unites the information of all colour channels. Advanced field programmable gate arrays represent an ideal platform for the parallel processing of multiple channels. The effective implementation presupposes however a high programming expenditure. On the example of the colour filter implementation, arising problems are analyzed and the chosen solution method is presented.
Schellhorn, M.; Rosenberger, M.; Correns, M.; Blau, M.; G�pfert, A.; R�ckwardt, M.; Linss, G.
Left ventricular myocardial mass determination by contrast enhanced colour Doppler compared with magnetic resonance imaging
Objective: To assess the feasibility of using contrast enhanced colour Doppler echocardiography to determine left ventricular (LV) mass and to compare its accuracy with LV mass obtained by magnetic resonance imaging (MRI). Methods: Images were acquired in the short axis plane of the heart, derived from coronal and sagittal scout views and double oblique angulation. The LV mass was calculated by two methods: Simpson�s rule and the area�length method. Levovist (Schering AG, Berlin, Germany) 2.5 g was given by slow intravenous bolus or infusion over about 45 seconds for contrast imaging. LV images were captured in the apical two chamber, four chamber, and three chamber views. Each contrast harmonic colour Doppler image was converted to a cavity-only image by simple image mathematics. Results: 27 (77.1%) of the patients (mean (SD) age 66.2 (8.9) years) were men. There was a mean (SD) interval of 6.6 (8.6) days (range 0�27 days) between echocardiography and MRI. The mean (SD) LV mass determined by MRI Simpson�s rule method was 171.0 (52.4) g (range 105.1�318.7 g). The mean LV mass (SD) determined by the echocardiographic Simpson�s rule method was 178.2 (47.0) g (range 112.6�307.6 g). The mean (SD) MRI area�length LV mass was 187.3 (64.5) g (range 109.0�393.6 g). The linear regression correlation between LV mass determined by MRI Simpson�s and echocardiographic Simpson�s methods was excellent (y ?=? 1.022x, R2 ?=? 0.986) with a mean (SD) difference of 7.20 (20.9) g. The linear regression correlation between the MRI area�length LV mass and MRI Simpson�s LV mass was excellent (y ?=? 1.101x, R2 ?=? 0.989) with a mean (SD) difference of 16.3 (22.3) g. Conclusions: LV mass may be obtained reliably by contrast enhanced colour Doppler and two dimensional echocardiography. The contrast Doppler method accurately determines LV mass with excellent agreement with the MRI technique.
Bezante, G P; Chen, X; Molinari, G; Valbusa, A; Deferrari, L; Sebastiani, V; Yokoyama, N; Steinmetz, S; Barsotti, A; Schwarz, K Q
ICL: The Image Composition Language
NASA Technical Reports Server (NTRS)
The Image Composition Language (ICL) provides a convenient way for programmers of interactive graphics application programs to define how the video look-up table of a raster display system is to be loaded. The ICL allows one or several images stored in the frame buffer to be combined in a variety of ways. The ICL treats these images as variables, and provides arithematic, relational, and conditional operators to combine the images, scalar variables, and constants in image composition expressions. The objective of ICL is to provide programmers with a simple way to compose images, to relieve the tedium usually associated with loading the video look-up table to obtain desired results.
Foley, James D.; Kim, Won Chul
Localisation of ventricular septal defects by simultaneous display of superimposed colour Doppler and cross sectional echocardiographic images.
Precise non-invasive localisation of the site of a small ventricular septal defect was attempted using a new technique that simultaneously combines conventional cross sectional echocardiography with a Doppler system by superimposing the colour coded direction and velocity of blood flow directly on to real time ultrasound images. Twenty three patients with unoperated ventricular septal defects and a further eight after surgical closure were studied; 12 children with normal hearts served as controls. A colour coded blood flow jet entering the right ventricle during systole was identified in all 23 unoperated patients, in 11 of whom the defect was too small to be visualised by conventional cross sectional echocardiography. The colour Doppler technique precisely located 19 perimembranous and five trabecular defects (one patient had two defects). Five of the postoperative patients were without clinical evidence of a significant shunt but had pansystolic murmurs. In each of these five, trans-septal shunt blood flow as demonstrated by colour Doppler images whereas in only three of these patients was the residual defect large enough to be visualised by conventional cross sectional echocardiography. Three postoperative patients had no murmurs and showed no residual shunt on colour Doppler images. This was confirmed at cardiac catheterisation. There were no false positive results among the controls. This technique is useful for the more accurate diagnosis and location of ventricular septal defects and may help in assessing their natural or surgical closure. Images
Ortiz, E; Robinson, P J; Deanfield, J E; Franklin, R; Macartney, F J; Wyse, R K
Colour of fat, and colour, fatty acid composition and sensory characteristics of muscle from heifers offered alternative forages to grass silage in a finishing ration.
The effect of type of silage offered to beef heifers during the finishing period on aspects of beef quality was determined. In two experiments, a diet based on grass silage (GS) was compared with a diet based on maize silage (MS) or whole-crop wheat silage (WCW). Compared to the GS-based diet, increasing the amount of MS linearly increased fat whiteness while the increase in fat whiteness due to WCW was dependent on the stage of crop maturity at harvesting. There was no effect of diet on muscle colour or on muscle pH measured at 48h post-mortem, drip loss, taste panel traits after 14days ageing or shear force values at 2, 7 or 14days ageing. The alternative silages decreased the n-3 polyunsaturated fatty acid proportion and increased the linoleic:linolenic acid ratio in intramuscular lipid. It is concluded that type of silage affects fat colour and fatty acid composition of muscle but not the other muscle characteristics examined. PMID:23806853
Moloney, A P; Mooney, M T; Kerry, J P; Stanton, C; O'Kiely, P
Hard shell gas-filled contrast enhancement particles for colour Doppler ultrasound imaging of tumors�
Hollow hard shell particles of 200 nm and 2 micron diameter with a 10 nm thick porous silica shell have been synthesized using polystyrene templates and a sol�gel process. The template ensures than the hollow particles are monodispersed, while the charged silica surface ensures that they remain suspended in solution for weeks. When filled with perfluorocarbon gas, the particles behave as an efficient contrast agent for colour Doppler ultrasound imaging in human breast tissue. The silica shell provides unique properties compared to conventional soft shell particles employed as ultrasound contrast agents: uniform size control, strong adsorption to tissue and cells immobilizing particles at the tissue injection site, a long imaging lifetime, and a silica surface that can be easily modified with biotargeting ligands or small molecules to adjust the surface charge and polarity.
Martinez, H. Paul; Kono, Yuko; Blair, Sarah L.; Sandoval, Sergio; Wang-Rodriguez, Jessica
Localisation of ventricular septal defects by simultaneous display of superimposed colour Doppler and cross sectional echocardiographic images
Precise non-invasive localisation of the site of a small ventricular septal defect was attempted using a new technique that simultaneously combines conventional cross sectional echocardiography with a Doppler system by superimposing the colour coded direction and velocity of blood flow directly on to real time ultrasound images. Twenty three patients with unoperated ventricular septal defects and a further eight after
E Ortiz; P J Robinson; J E Deanfield; R Franklin; F J Macartney; R K Wyse
Intelligent scissors for image composition
We present a new, interactive tool called Intelligent Scissors which we use for image segmentation and composition. Fully auto- mated segmentation is an unsolved problem, while manual tracing is inaccurate and laboriously unacceptable. However, Intelligent Scissors allow objects within digital images to be extracted quickly and accurately using simple gesture motions with a mouse. When the gestured mouse position comes
Eric N. Mortensen; William A. Barrett
Color is a feature of the great majority of content-based image retrieval systems. However the robustness, effectiveness, and efficiency of its use in image indexing are still open issues. This paper provides a comprehensive survey of the methods for color image indexing and retrieval described in the literature. In particular, image preprocessing, the features used to represent color information, and
Raimondo SCHETTINI; Gianluigi CIOCCA; Silvia ZUFFI
Colour Image Retrieval and Object Recognition Using the Multimodal Neighbourhood Signature
. A novel approach to colour-based object recognition and imageretrieval-the multimodal neighbourhood signatureis proposed. Objectappearance is represented by colour-based features computed from imageneighbourhoods with multi-modal colour density function. Stable invariantsare derived from modes of the density function that are robustly located bythe mean shift algorithm. The problem of extracting local invariant colourfeatures is addressed directly, without a need for prior...
Jiri Matas; Dimitri Koubaroulis; Josef Kittler
Healthy and fungal-damaged wheat kernels infected by the species of storage fungi namely Penicillium spp., Aspergillus glaucus, and A. niger were scanned using short-wave near-infrared hyperspectral imaging system in the 700�1100 nm wavelength range and an area scan colour camera. Multivariate image (MVI) analysis was used to reduce the dimensionality of the hyperspectral data and to select the significant wavelength
C. B. Singh; D. S. Jayas; J. Paliwal; N. D. G. White
Fungal Damage Detection in Wheat Using Short-Wave Near-Infrared Hyperspectral and Digital Colour Imaging
Healthy and fungal-damaged wheat kernels infected by the species of storage fungi, namely Penicillium spp., Aspergillus glaucus, and A. niger, were scanned using a short-wave near-infrared hyperspectral imaging system in the 700�1100 nm wavelength range and an area scan colour camera. A multivariate image analysis was used to reduce the dimensionality of the hyperspectral data and to select the significant
C. B. Singh; D. S. Jayas; J. Paliwal; N. D. G. White
Power-scalable, polarization-stable, dual-colour DFB fibre laser system for CW terahertz imaging
Imaging with electromagnetic radiation in the terahertz (THz) range has received a large amount of attention during recent years. THz imaging systems have diverse potential application areas such as security screening, medical diagnostics and non-destructive testing. We will discuss a power-scalable, dual-colour, polarization-maintaining distributed feedback (DFB) fibre laser system with an inherent narrow linewidth from the DFB fibre laser oscillators.
Finn Eichhorn; Jens Engholm Pedersen; Peter Uhd Jepsen
Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects. PMID:24647930
Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette
Colour tuning in human visual cortex measured with functional magnetic resonance imaging
The primate retina contains three classes of cones, the L, M and S cones, which respond preferentially to long-, middle- and short-wavelength visible light, respectively. Colour appearance results from neural processing of these cone signals within the retina and the brain. Perceptual experiments have identified three types of neural pathways that represent colour: a red-green pathway that signals differences between
Stephen Engel; Xuemei Zhang; Brian Wandell
Analysis of foveal avascular zone in colour fundus images for grading of diabetic retinopathy severity.
Diabetic retinopathy (DR) is a sight threatening complication due to diabetes mellitus that affects the retina. At present, the classification of DR is based on the International Clinical Diabetic Retinopathy Disease Severity. In this paper, FAZ enlargement with DR progression is investigated to enable a new and an effective grading protocol DR severity in an observational clinical study. The performance of a computerised DR monitoring and grading system that digitally analyses colour fundus image to measure the enlargement of FAZ and grade DR is evaluated. The range of FAZ area is optimised to accurately determine DR severity stage and progression stages using a Gaussian Bayes classifier. The system achieves high accuracies of above 96%, sensitivities higher than 88% and specificities higher than 96%, in grading of DR severity. In particular, high sensitivity (100%), specificity (>98%) and accuracy (99%) values are obtained for No DR (normal) and Severe NPDR/PDR stages. The system performance indicates that the DR system is suitable for early detection of DR and for effective treatment of severe cases. PMID:21097305
Ahmad Fadzil, M; Ngah, Nor Fariza; George, Tara M; Izhar, Lila I; Nugroho, Hermawan; Adi Nugroho, Hanung
Colour 3-D electronic imaging of the surface of the human body
The NRC laboratories have developed a laser scanning technique to digitize shapes and colours in registration. The technique, known as synchronized scanning, is capable of digitizing topography as small as the relief of a bare finger tip, showing a clear picture of the skin structure (essentially a clean fingerprint without distortion), as well as the shape and size of body
Marc Rioux
Modulation of the phenolic composition and colour of red wines subjected to accelerated ageing by controlling process variables.
The aim of the present work was to evaluate the effect of the main factors conditioning accelerated ageing processes (oxygen dose, chip dose, wood origin, toasting degree and maceration time) on the phenolic and chromatic profiles of red wines by using a multivariate strategy based on experimental design methodology. The results obtained revealed that the concentrations of monomeric anthocyanins and flavan-3-ols could be modified through the application of particular experimental conditions. This fact was particularly remarkable since changes in phenolic profile were closely linked to changes observed in chromatic parameters. The main strength of this study lies in the possibility of using its conclusions as a basis to make wines with specific colour properties based on quality criteria. To our knowledge, the influence of such a large number of alternative ageing parameters on wine phenolic composition and chromatic attributes has not been studied previously using a comprehensive experimental design methodology. PMID:25038676
Gonz�lez-S�iz, J M; Esteban-D�ez, I; Rodr�guez-Tecedor, S; P�rez-Del-Notario, N; Arenzana-R�mila, I; Pizarro, C
Effects of Dietary Chromium Methionine on Growth Performance, Carcass Composition, Meat Colour and Expression of the Colour-related Gene Myoglobin of Growing-finishing Pigs
To investigate the effect of dietary chromium (Cr) as Cr methionine (CrMet) on growth performance, carcass traits, pork quality, meat colour and expression of meat colour-related genes in growing-finishing pigs, 189 crossbred Duroc�(Landrace�Yorkshire) growing-finishing pigs (male, castrated, average initial BW 74.58�1.52 kg) were selected and randomly allocated into four groups. Dietary treatments per kg of feed were as follows: 0 (CT), 0.3 mg/kg (T1), 0.6 mg/kg (T2) and 0.9 mg/kg (T3) Cr (in the form of CrMet; as-fed basis), and each treatment was replicated five times with 8 to 10 pigs per replicate pen. During the 28 d of the experiment, both the ADG and the ADFI increased linearly (p<0.05) as the level of dietary Cr increased. The F/G ratio decreased linearly (p<0.05). As dietary Cr increased, loin muscle areas (linear, p = 0.013) and average backfat thickness (linear, p = 0.072) decreased. Shear force (linear, p = 0.070) and Commission Internationale de I��clairage (CIE) redness (quadratic, p = 0.028) were increased. In addition, CIE Lightness (quadratic, p = 0.053) were decreased as dietary Cr increased. As dietary Cr increased, total myglobin (Mb) content (quadratic, p = 0.015) and the mb mRNA levels (quadratic, p = 0.046) in longissimus muscles of pigs were up-regulated. In conclusion, supplementation of dietary Cr improved growth and meat colour, but increased shear force and decreased IMF reduced palatability of longissimus muscles. Moreover, the increasing total Mb content and mb mRNA levels indicated that CrMet dietary supplementation may improve meat colour via up-regulating expression of the mb gene.
Li, Y. S.; Zhu, N. H.; Niu, P. P.; Shi, F. X.; Hughes, C. L.; Tian, G. X.; Huang, R. H.
Composite ultrasound imaging apparatus and method
An imaging apparatus and method for use in presenting composite two dimensional and three dimensional images from individual ultrasonic frames. A cross-sectional reconstruction is applied by using digital ultrasound frames, transducer orientation and a known center. Motion compensation, rank value filtering, noise suppression and tissue classification are utilized to optimize the composite image.
Morimoto, Alan K. (Albuquerque, NM); Bow, Jr., Wallace J. (Albuquerque, NM); Strong, David Scott (Albuquerque, NM); Dickey, Fred M. (Albuquerque, NM)
Composite ultrasound imaging apparatus and method
An imaging apparatus and method for use in presenting composite two dimensional and three dimensional images from individual ultrasonic frames. A cross-sectional reconstruction is applied by using digital ultrasound frames, transducer orientation and a known center. Motion compensation, rank value filtering, noise suppression and tissue classification are utilized to optimize the composite image. 37 figs.
Morimoto, A.K.; Bow, W.J. Jr.; Strong, D.S.; Dickey, F.M.
Modification to the atmospheric correction of SeaWiFS ocean colour images over turbid waters
The successful exploitation of remotely sensed observations of water colour in the coastal zone requires atmospheric correction methods that can determine water reflectance from top-of-atmosphere radiometric measurements over waters containing significant non-phytoplanktonic particulate material. These so-called Case II waters often have significant water leaving radiance at near infra-red (NIR) wavelengths which invalidates conventional �dark pixel� atmospheric correction procedures, including those
S. J. Lavender; M. H. Pinkerton; G. F. Moore; J. Aiken; D. Blondeau-Patissier
Colour stabilisation of wood composites using polyethylene glycol and melamine resin
Photo-yellowing of native and polyethylene glycol (PEG) modified wood and wood\\/melamine resin composites was studied by means\\u000a of FTIR-ATR technique and colourimetry (CIE L*a*b* method). The discolouration $$\\u000a\\\\mathrm{\\\\Delta }\\u000a$$E shows a�systematic asymptotic trend towards higher values with increasing irradiation time. Yellowing proceeds faster in\\u000a natural wood compared to wood\\/melamine resin composites. Nevertheless, long-term irradiation experiments show that the
Uwe M�ller; Melanie Steiner
Nutrition-related status and granulation tissue colour of pressure ulcers evaluated by digital image analysis in older patients.
Objective: Granulation tissue colour may be an indicator for nutritional assessment in pressure ulcer (PU) care. This study evaluated the relationship between nutritional status, anaemia and diabetes, and granulation tissue colour of PUs by colour analysis of digital photographs in the clinical setting. Method: The cross-sectional study included 42 older patients with 51 full-thickness PUs from 10 institutions. Patient demographics, wound status, nutritional status and dietary intakes were obtained from medical charts. From a wound image, the granulation red index was processed by computer software and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) was calculated. Results: Haemoglobin levels were positively associated with %GRI80 levels (p=0.007) in the crude model, but not in the adjusted model (p=0.260). The interaction term between diabetes and protein intake was significantly associated with %GRI80 levels in the adjusted models (p=0.010). At protein intakes of 0.95 g/kg or higher, diabetic wounds exhibited lower %GRI80 levels than non-diabetic wounds (p=0.002). At protein intakes of less than 0.95 g/kg, %GRI80 levels did not differ between diabetic and non-diabetic patients (p=0.247). Protein intakes of 0.95 g/kg or higher were associated with higher %GRI80 levels in non-diabetic patients (p=0.015), but not in diabetic patients (p=0.127). Conclusion: Granulation tissue colour, evaluated by the objective and quantitative analysis of digital photography, is related to haemoglobin level, diabetes and dietary intakes in clinical settings. Declaration of interest: This study was funded by a grant from the Japanese Society of Pressure Ulcers and a Grant-in-Aid for Fellows of Japan Society for the Promotion of Science (#22-2766). The funding organisations had no role in the design, data collection, analysis, review, or approval of the manuscript. The authors report no relevant conflict of interests. PMID:24762383
Iizaka, S; Koyanagi, H; Sasaki, S; Sekine, R; Konya, C; Sugama, J; Sanada, H
Assessment of interventricular septal motion using colour tissue Doppler imaging in adult patients with atrial septal defect.
We aimed to characterize changes in interventricular septum (IVS) motion and any relationship between them and the pulmonary-to-systemic flow ratio (Qp/Qs) in adult patients with atrial septal defect (ASD). Patients and controls were studied using colour tissue Doppler imaging (TDI). The septum length (SL) and distance from the colour change point (CCP) on the IVS to the aortic valve (the CCP distance) were measured on parasternal long axis views. Values normalized for body surface area, and the CCP distance to SL ratio, were calculated. Qp/Qs values were correlated with CCP distance, normalized CCP distance and CCP distance:SL ratio. Statistically significant differences in CCP distance, normalized CCP distance and CCP distance:SL ratio were found between the two groups. In the ASD group, there was no correlation between Qp/Qs and the echocardiographic measurements. The point between the motions in two different directions from the IVS shifted toward the apex in ASD patients compared with controls, and may be a mechanism involved in paradoxical septal motion. PMID:14997700
Kardesoglu, E; Cebeci, B S; Celik, T; Cingozbay, B Y; Dincturk, M; Demiralp, E
Traffic sign recognition using colour information
In this paper, we present a novel approach for the detection and recognition of traffic signs. Colour images are acquired by a camera mounted in a car. In the first step, these images are colour segmented with a pixel classifier. Colour combinations which are characteristic for traffic signs generate hypotheses. These hypotheses are verified using a pictogram classifier.Our system has
W. Ritter; F. Stein; R. Janssen
Colour Doppler Imaging of Ophthalmic Artery and Central Retinal Artery in Glaucoma Patients with and without Diabetes Mellitus
Purpose: To assess the ocular blood flow in Diabetic and non-Diabetic Primary Open Angle Glaucoma (POAG) patients. Design: Prospective comparitive study. Material and Methods: A total 100 eyes of 50 POAG patients was included in the study and divided into two groups, Group 1 (25 POAG patients without Diabetes mellitus) and Group 2 (25 POAG patients with Diabetes mellitus). Colour Doppler Imaging (CDI) of Ophthalmic artery and Central retinal artery were studied and peak systolic velocity (V max), End diastolic velocity (V min) and Resistivity Index (RI) were assessed. Results: Ocular blood flow in Group 2 showed a reduction in V max, V min and increased RI compared to Group I with a statistically significant reduction in the central retinal artery flow (V max (p=0.01), V min (p=0.07) and RI (p=0.03). Conclusion: CDI showed a significant reduction in the ocular blood flow of POAG patients with Diabetes mellitus.
Kumar, M. Ashok; Selvasundari, S.; Prakash, M. L.
Effect of dietary astaxanthin on the growth performance, lipid composition and post-mortem skin colouration of red porgy Pagrus pagrus
A 120-day feeding trial was conducted to assess the possible effect of including dietary astaxanthin (ASTX), for different\\u000a lengths of time prior to harvest, on red porgy growth performance, lipid and fatty acid composition and post-mortem skin colour.\\u000a Four treatment groups were established with fish of initial weight of approximately 220�g. Control group was fed on a control\\u000a diet (with
C. T. Kalinowski; L. E. Robaina; M. S. Izquierdo
Colour detection thresholds in faces and colour patches.
Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status. PMID:24344549
Tan, Kok Wei; Stephen, Ian D
Electrochemically prepared poly(o-phenylenediamine) � Prussian blue composite film for a three-colour expressible ECD material
Both Prussian blue (PB) and poly(o-phenylenediamine) (PoPD) were easily electrodeposited as stable films onto a transparent indium tin oxide (ITO) electrode. The voltammogram of the PB film showed a reversible sharp redox peak current at about 0.25 V. Although the colour change was caused by altering the applied potentials, no colour change was seen after about 104 repetitions. The PoPD
J. Yano; K. Terayama; S. Yamasaki
Quantitative clinical marker extraction from colour fundus images for non-proliferative Diabetic Retinopathy grading
This paper proposes robust methods for segmentation of clinically significant features of fundus images, from the point of view of detection and gradation of Diabetic Retinopathy as well as Maculopathy. After pre-processing to remove intra- and inter- image illumination variances, the optic disk and fovea are detected and exudates, haemorrhages and microaneurysms are segmented out using modified morphological techniques. The
Sunrita Poddar; Bibhash Kumar Jha; Chandan Chakraborty
Colour constancy is traditionally interpreted as the stable appearance of the colour of a surface despite changes in the spectral composition of the illumination. When colour constancy has been assessed quantitatively, however, by observers making matches between surfaces illuminated by different sources, its completeness has been found to be poor. An alternative operational approach to colour constancy may be taken which concentrates instead on detecting the underlying chromatic relationship between the parts of a surface under changes in the illuminant. Experimentally the observer's task was to determine whether a change in the appearance of a surface was due to a change in its reflecting properties or to a change in the incident light. Observers viewed computer simulations of a row of three Mondrian patterns of Munsell chips. The centre pattern was a reference pattern illuminated by a simulated, spatially uniform daylight; one of the outer patterns was identical but illuminated by a different daylight; and the other outer pattern was equivalent but not obtainable from the centre pattern by such a change in illuminant. Different patterns and different shifts in daylight were generated in each experimental trial. The task of the observer was to identify which of the outer patterns was the result of an illuminant change. Observers made reliable discriminations of the patterns with displays of durations from several seconds to less than 200 ms, and, for one observer, with displays of 1 ms. By these measures, human observers appear capable of colour constancy that is extremely rapid, and probably preattentive in origin. PMID:1408163
Foster, D H; Craven, B J; Sale, E R
Terahertz imaging of aircraft composites
Damaged aircraft composites were prepared simulating voids, delaminations, puncture holes, burns and paint removal. Terahertz time domain spectroscopy in reflection configuration was assessed as a non-destructive evaluation (NDE) technique and compared to traditional NDE techniques.
Matthew J. Bohn; Christopher D. Stoik; James L. Blackshire
Kilauea Flow: Composite Image of Viewing Area
This composite image of the County viewing area in Kalapana combines a thermal image, showing the active flow lobe in red and yellow, with a normal photograph. The lighter yellow areas are locations of active breakouts at the flow margin, and smoke can be seen originating from the flow front where b...
Rejuvenating the appearance of Seurat's A Sunday on La Grande Jatte - 1884 using colour and imaging science techniques: a simulation
Georges Seurat first used his divisionist painting technique on A Sunday on La Grande Jatte - 1884 beginning in October 1885. Painting with pigments representing colours seen in the visible spectrum that were minimally mixed on the palette and using divided brushstrokes, he aimed to impart luminosity to the surface and to explore 19th century ideas of colour theory, such
Roy S Berns; Francisco H Imai; Lawrence A Taplin; Siobhan Byrns; Francesca Casadio; Inge Fiedler; Christopher Gallagher; Alan Newman
Digital colour management system for colour parameters reconstruction
NASA Astrophysics Data System (ADS)
Digital Colour Management System (DCMS) and its application to new adaptive camouflage system are presented in this paper. The DCMS is a digital colour rendering method which would allow for transformation of a real image into a set of colour pixels displayed on a computer monitor. Consequently, it can analyse pixels' colour which comprise images of the environment such as desert, semi-desert, jungle, farmland or rocky mountain in order to prepare an adaptive camouflage pattern most suited for the terrain. This system is described in present work as well as the use the subtractive colours mixing method to construct the real time colour changing electrochromic window/pixel (ECD) for camouflage purpose. The ECD with glass/ITO/Prussian Blue(PB)/electrolyte/CeO2-TiO2/ITO/glass configuration was assembled and characterized. The ECD switched between green and yellow after +/-1.5 V application and the colours have been controlled by Digital Colour Management System and described by CIE LAB parameters.
Grudzinski, Karol; Lasmanowicz, Piotr; Assis, Lucas M. N.; Pawlicka, Agnieszka; Januszko, Adam
A comparative analysis of pre-processing techniques in colour retinal images
NASA Astrophysics Data System (ADS)
Diabetic retinopathy (DR) is a chronic disease of the ocular retina, which most of the times is only discovered when the disease is on an advanced stage and most of the damage is irreversible. For that reason, early diagnosis is paramount for avoiding the most severe consequences of the DR, of which complete blindness is not uncommon. Unsupervised or supervised image processing of retinal images emerges as a feasible tool for this diagnosis. The preprocessing stages are the key for any further assessment, since these images exhibit several defects, including non uniform illumination, sampling noise, uneven contrast due to pigmentation loss during sampling, and many others. Any feasible diagnosis system should work with images where these defects were compensated. In this work we analyze and test several correction techniques. Non uniform illumination is compensated using morphology and homomorphic filtering; uneven contrast is compensated using morphology and local enhancement. We tested our processing stages using Fuzzy C-Means, and local Hurst (self correlation) coefficient for unsupervised segmentation of the abnormal blood vessels. The results over a standard set of DR images are more than promising.
Salvatelli, A.; Bizai, G.; Barbosa, G.; Drozdowicz, B.; Delrieux, C.
IN NATURE of July 15 there is given an abstract of a paper by Dr. F. W. Edridge-Green in which he gives reasons for supposing that the sensation produced by spectral yellow is a simple sensation, and not a compound of red and green, as supposed by the Young-Helmholtz theory. In 1872 I read a paper on colour sensation before
John Aitken
Colour Image Comparison and Visual Perception: A Process for Descriptor Validation
In some specific problems, a gray scale analysis is unfortunately not sufficient: color is necessarily required. Generally in these kinds of problems it is necessary to be able to quantify the quality of an image in accordance with a reference one and the quality of a process in accordance with another one (for example to evaluate degradations introduced when compressing
Eric Favier; Eric Dinet; Alain Tremeau
Bright Retinal Lesions Detection using Colour Fundus Images Containing Reflective Features
In the last years the research community has developed many techniques to detect and diagnose diabetic retinopathy with retinal fundus images. This is a necessary step for the implementation of a large scale screening effort in rural areas where ophthalmologists are not available. In the United States of America, the incidence of diabetes is worryingly increasing among the young population. Retina fundus images of patients younger than 20 years old present a high amount of reflection due to the Nerve Fibre Layer (NFL), the younger the patient the more these reflections are visible. To our knowledge we are not aware of algorithms able to explicitly deal with this type of reflection artefact. This paper presents a technique to detect bright lesions also in patients with a high degree of reflective NFL. First, the candidate bright lesions are detected using image equalization and relatively simple histogram analysis. Then, a classifier is trained using texture descriptor (Multi-scale Local Binary Patterns) and other features in order to remove the false positives in the lesion detection. Finally, the area of the lesions is used to diagnose diabetic retinopathy. Our database consists of 33 images from a telemedicine network currently developed. When determining moderate to high diabetic retinopathy using the bright lesions detected the algorithm achieves a sensitivity of 100% at a specificity of 100% using hold-one-out testing.
Giancardo, Luca [ORNL; Karnowski, Thomas Paul [ORNL; Chaum, Edward [ORNL; Meriaudeau, Fabrice [ORNL; Tobin Jr, Kenneth William [ORNL; Li, Yaquin [University of Tennessee, Knoxville (UTK)
Evaluation of ocular surface temperature and retrobulbar haemodynamics by infrared thermography and colour Doppler imaging in patients with glaucoma
Background Ocular surface temperature (OST) could berelated to retrobulbar haemodynamics in patients with glaucoma. Aims To compare OST measurements in patients with glaucoma and healthy controls, and to investigate the correlation between OST, intraocular pressure (IOP) and retrobulbar haemodynamics in patients with glaucoma. Methods 32 patients with primary open?angle glaucoma (POAG) and 40 controls were included in the study. The parameters considered both in patients with POAG and in controls were IOP and OST values measured by infrared ocular thermography. Colour Doppler imaging was used to determine haemodynamic parameters in ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCAs) in patients with POAG. Results OST values were significantly lower in patients with POAG than in controls (p<0.001). OST was negatively related with resistivity index of OA (p<0.001), CRA (p?=?0.001) and SPCAs (p<0.001), and positively related with end?diastolic velocity of OA (p?=?0.02) and SPCAs (p?=?0.05). Conclusion This study suggested that OST could be a marker of impaired retrobulbar haemodynamics in patients with glaucoma.
Galassi, Fernando; Giambene, Barbara; Corvi, Andrea; Falaschi, Giacomo
The use of digital imaging for colour matching and communication in restorative dentistry
Objective To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'.Methods Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3.
M D Russell; B W Moss; F D Jarad
A Comparison of Computational Colour Constancy Algorithms. Part Two: Experiments on Image Data
Abstract�We test a number ,of the ,leading computational ,color constancy ,algorithms ,using a comprehensive,set of images. These were of 33 different scenes under 11 different sources representative ofcommon illumination conditions. The algorithms studied include two gray world methods, a version of the Retinex method, several variants of Forsyth's gamut-mapping method, Cardei et al.'s neural net method, and Finlayson et al.'s
K. Barnard; L. Martin; A. Coath; B. Funt
Detecting natural changes of cone-excitation ratios in simple and complex coloured images.
Ratios of excitations in each cone-photoreceptor class produced by light reflected from pairs of surfaces in a scene are almost invariant under natural illuminant changes. The stability of these spatially defined ratios may explain the remarkable ability of human observers to efficiently discriminate illuminant changes from changes in surface reflectances. Spatial cone-excitation ratios are not, however, exactly invariant. This study is concerned with observers' sensitivity to these invariance violations. Simulations of Mondrian paintings with either 49 or two natural surfaces under Planckian illuminants were presented as images on a computer-controlled display in a two-interval experimental design: in one interval, the surfaces underwent an illuminant change; in the other interval, the surfaces underwent the same change but the images were then corrected so that, for each cone class, ratios of excitations were preserved exactly. Although the intervals with corrected images corresponded individually to highly improbable natural events, observers systematically misidentified them as containing the illuminant changes, the probability of error increasing as the violation of invariance in the other interval increased. For the range of illuminants and surfaces tested, sensitivity to violations of invariance was found to depend on cone class: it was greatest for long-wavelength-sensitive cones and least for short-wavelength-sensitive cones. Spatial cone-excitation ratios, or some closely related quantities, seem to be the cues preferred by observers for making inferences about surface illuminant changes. PMID:9332018
Nascimento, S M; Foster, D H
Compositing 3-D rendered images
The complexity of anti-aliased 3-D rendering systems can be controlled by using a tool-building approach like that of the UNIX™ text-processing tools. Such an approach requires a simple picture representation amenable to anti-aliasing that all rendering programs can produce, a compositing algorithm for that representation and a command language to piece together scenes. This paper advocates a representation that combines
Tom Duff
True three-colour photoceramic
This paper presents the true three-colour photoceramic, introduced by the authors since 1992, which allows wide new possibilities in the field of the ceramic decoration, for reproduction on ceramic (majolica, porcelain, earthenware, etc.) surfaces of images either photographic or painted images or even directly coming from computer-made image files. The correspondent technological process used to produce this kind of decoration
A. Krajewski; L. Paci
Printing colour at the optical diffraction limit.
The highest possible resolution for printed colour images is determined by the diffraction limit of visible light. To achieve this limit, individual colour elements (or pixels) with a pitch of 250�nm are required, translating into printed images at a resolution of ?100,000 dots per inch (d.p.i.). However, methods for dispensing multiple colourants or fabricating structural colour through plasmonic structures have insufficient resolution and limited scalability. Here, we present a non-colourant method that achieves bright-field colour prints with resolutions up to the optical diffraction limit. Colour information is encoded in the dimensional parameters of metal nanostructures, so that tuning their plasmon resonance determines the colours of the individual pixels. Our colour-mapping strategy produces images with both sharp colour changes and fine tonal variations, is amenable to large-volume colour printing via nanoimprint lithography, and could be useful in making microimages for security, steganography, nanoscale optical filters and high-density spectrally encoded optical data storage. PMID:22886173
Kumar, Karthik; Duan, Huigao; Hegde, Ravi S; Koh, Samuel C W; Wei, Jennifer N; Yang, Joel K W
Printing colour at the optical diffraction limit
NASA Astrophysics Data System (ADS)
The highest possible resolution for printed colour images is determined by the diffraction limit of visible light. To achieve this limit, individual colour elements (or pixels) with a pitch of 250 nm are required, translating into printed images at a resolution of ~100,000 dots per inch (d.p.i.). However, methods for dispensing multiple colourants or fabricating structural colour through plasmonic structures have insufficient resolution and limited scalability. Here, we present a non-colourant method that achieves bright-field colour prints with resolutions up to the optical diffraction limit. Colour information is encoded in the dimensional parameters of metal nanostructures, so that tuning their plasmon resonance determines the colours of the individual pixels. Our colour-mapping strategy produces images with both sharp colour changes and fine tonal variations, is amenable to large-volume colour printing via nanoimprint lithography, and could be useful in making microimages for security, steganography, nanoscale optical filters and high-density spectrally encoded optical data storage.
Kumar, Karthik; Duan, Huigao; Hegde, Ravi S.; Koh, Samuel C. W.; Wei, Jennifer N.; Yang, Joel K. W.
NPU-Based Image Compositing in a Distributed Visualization System
This paper describes the first use of a network processing unit (NPU) to perform hardware-based image composition in a distributed rendering system. The image composition step is a notorious bottleneck in a clustered rendering system. Furthermore, image compositing algorithms do not necessarily scale as data size and number of nodes increase. Previous researchers have addressed the composition problem via software
David Pugmire; Laura Monroe; Carolyn Connor Davenport; Andrew Dubois; David Dubois; Stephen Poole
Colour constancy remains an important topic in colour research today, as it has for more than a century. Technological advances in digital capture and image processing have expanded studies of this constancy from individual colour patches to entire complex images. In Land's Colour Mondrian experiment he controlled uniform illumination over an array of more than 100 coloured papers to demonstrate
John McCann; Carinna Parraman; Alessandro Rizzi
Optical spectroscopy and imaging of colour centres in lithium fluoride crystals and thin films irradiated by 3 MeV proton beams
NASA Astrophysics Data System (ADS)
Lithium fluoride is a well-known dosimeter material and it is currently under investigation also for high-resolution radiation imaging detectors based on colour centre photoluminescence. In order to extend their applications, proton beams of 3 MeV energy, produced by a linear accelerator, were used to irradiate LiF crystals and thin films in the fluence range of 1010�1015 protons/cm2. The irradiation induces the formation of colour centres, mainly the primary F centre and the aggregate F2 and F3+ defects, which are stable at room temperature. By optical pumping in the blue spectral region, the F2 and F3+ centres emit broad photoluminescence bands in the visible spectral range. By conventional fluorescence microscopy, the integrated photoluminescence intensity was carefully measured in LiF crystals and thin films as a function of the irradiation fluence: a linear optical response was obtained in a large range of fluence, which is dependent on the used LiF samples. Colour centres concentrations were estimated in LiF crystals by optical absorption spectroscopy. It was possible to record the transversal proton beam intensity profile by acquiring the photoluminescence image of the irradiated spots on LiF films.
Piccinini, M.; Ambrosini, F.; Ampollini, A.; Carpanese, M.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M.
ERIC Educational Resources Information Center
What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called�
Hughes, S. W.
Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.
Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours. PMID:23224278
Rohde, Katja; Papiorek, Sarah; Lunau, Klaus
NSDL National Science Digital Library
The endless hues and shades of colors fascinate many persons, including interior-designers, fashionistas, and those who study the workings of the human eye. This particular site is "a place to view, rate and review some lovely colours & palettes." The site contains a number of user forums where people may gather around the electronic glow of the screen to discuss and debate the merits of different colors, along with a place for users to submit their own fanciful and innovative colors. On the right-hand side of the home page, visitors can browse through the top-rated colors, newly added colors, and new palettes. Many of the colors have rather curious names, such as "wegobysundawn" and "victory or ignorance." Of course, there is space provided for visitors to give their own opinions on each color or palette. Overall, a compelling site, and one that will delight those with a penchant for the uses of color.
Imaging with lithium niobate/epoxy composites.
Lithium niobate, LiNbO3, is a very promising material for high temperature applications in non-destructive testing because of its high Curie temperature. However, for commercial applications LiNbO3 has often been neglected because of its low electromechanical coupling coefficients. This paper explores the potential of LiNbO3 composites, by means of room temperature characterization and measurements, for further use in operation in high temperature transducers. LiNbO3 composites of 1-3 connectivity in an epoxy matrix with volume fractions of LiNbO3 of 33% and 54% were fabricated. The composites were characterized by electrical impedance measurements and the results were compared with modelled impedance characteristics. Many parameters were predicted accurately, including an improvement of more than 75% in thickness mode electromechanical coupling coefficient, from kT=0.17 for bulk LiNbO3 to kT=0.32 for composite material. Some large discrepancies between simulation and experiment were also identified when a conventional one-dimensional model was used to calculate equivalent composite material parameters; however, finite element modelling was more accurate. After characterization, the composite was configured for use as a linear array. Functional measurements were conducted on steel blocks with a side drilled hole to represent a crack tip. This was detected by the array and visualized in time-of-flight diffraction B-scan images. PMID:15047325
Schmarje, N; Saillant, J F; Kirk, K J; Cochran, S
Upper extremity composite tissue allotransplantation imaging.
Objective: Upper extremity (UE) transplantation is the most commonly performed composite tissue allotransplantation worldwide. However, there is a lack of imaging standards for pre- and posttransplant evaluation. This study highlights the protocols and findings of UE allotransplantation toward standardization and implementation for clinical trials. Methods: Multimodality imaging protocols for a unilateral hand transplant candidate and a bilateral mid-forearm level UE transplant recipient include radiography, computed tomography (CT), magnetic resonance (MR) imaging, catheter angiography, and vascular ultrasonography. Pre- and posttransplant findings, including dynamic CT and MR performed for assessment of motor activity of transplanted hands, are assessed, and image quality of vessels and bones on CT and MR evaluated. Results: Preoperative imaging demonstrates extensive skeletal deformity and variation in vascular anatomy and vessel patency. Posttransplant images confirm bony union in anatomical alignment and patency of vascular anastomoses. Mild differences in rate of vascular enhancement and extent of vascular networks are noted between the 2 transplanted limbs. Dynamic CT and MR demonstrate a 15� to 30� range of motion at metacarpophalangeal joints and 90� to 110� at proximal interphalangeal joints of both transplanted hands at 8 months posttransplant. Image quality was slightly better for CT than for MR in the first subject, while MR was slightly better in the second subject. Conclusion: Advanced vascular and musculoskeletal imaging play an important role in surgical planning and can provide novel posttransplantation data to monitor the success of the procedure. Implementation of more standardized protocols should enable a more comprehensive assessment to evaluate the efficacy in clinical trials. PMID:23943677
George, Elizabeth; Mitsouras, Dimitrios; Kumamaru, Kanako K; Shah, Nehal; Smith, Stacy E; Schultz, Kurt; Deaver, Pamela M; Mullen, Katherine M; Steigner, Michael L; Gravereaux, Edwin C; Demehri, Shadpour; Bueno, Ericka M; Talbot, Simon G; Pomahac, Bohdan; Rybicki, Frank J
ERIC Educational Resources Information Center
Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children�
Banaschewski, Tobias; Ruppert, Sinje; Tannock, Rosemary; Albrecht, Bjorn; Becker, Andreas; Uebel, Henrik; Sergeant, Joseph A.; Rothenberger, Aribert
Colloidal approach to prepare colour blends from colourants with different solubility profiles.
Food colouring plays a vital and a determining role in the processing and the manufacturing of food products because the appearance of products is critical for attracting consumers and influencing their food choices. However, factors such as legislative restrictions, limited number of approved colourants and the processing, formulation and stability issues of the natural colourants severely limits the application of food colouring in actual product formats. Hence, finding alternatives to the currently utilised formulation practises, represents an important area of research. Here, we report a simple colloidal approach to prepare colour blends by co-incorporating colourants with contrasting aqueous solubility profiles in composite colloidal particles. Curcumin and indigocarmine were selected as water insoluble and water soluble food-grade colourants respectively and incorporated in the colloidal particles prepared from food protein-zein. Composite particles obtained by loading of curcumin and indigocarmine (at different ratios) had mean particle size ranging from 76 to 300nm. The spherical shape of the colloidal particles was confirmed using transmission electron microscopy and the colloidal dispersions were further characterised using UV-Vis and fluorescence spectroscopy. The incorporation of colourants in colloidal particles led to the generation of different shade of colour in yellow-green-blue range. The encapsulation also led to the stabilization of individual pigments against photodegradation. Such composite colloidal particles could potentially serve as an approach for developing tuneable colouring system for food and nutraceutical applications. PMID:23790940
Patel, A R; Heussen, P C M; Dorst, E; Hazekamp, J; Velikov, K P
Millimeter-wave imaging of composite materials
This work addresses the application and evaluates the potential of mm-wave imaging in the W-band (75-110 GHz) using samples of low-loss dielectric and composite materials with artificial defects. The initial focus is on the measurement of amplitude changes in the back scattered and forward-scattered fields. The c-scan system employs a focused beam antenna to provide spatial resolution of about one wavelength. A plane-wave model is used to calculate the effective reflection (or transmission) coefficient of multilayer test sample geometry. Theoretical analysis is used to optimize the measurement frequency for higher image contrast and to interpret the experimental results. Both reflection and transmission images, based on back scattered and forward-scattered powers, were made with Plexiglas and Kevlar/epoxy samples containing artificially introduced defects such as subsurface voids and disbonds. The results clearly indicate that mm-wave imaging has high potential for non-contact interrogation of low-loss materials.
Gopalsami, N.; Bakhtiari, S.; Dieckman, S.L.; Raptis, A.C.; Lepper, M.J.
Thermographic Imaging of Defects in Anisotropic Composites
NASA Technical Reports Server (NTRS)
Composite materials are of increasing interest to the aerospace industry as a result of their weight versus performance characteristics. One of the disadvantages of composites is the high cost of fabrication and post inspection with conventional ultrasonic scanning systems. The high cost of inspection is driven by the need for scanning systems which can follow large curve surfaces. Additionally, either large water tanks or water squirters are required to couple the ultrasonics into the part. Thermographic techniques offer significant advantages over conventional ultrasonics by not requiring physical coupling between the part and sensor. The thermographic system can easily inspect large curved surface without requiring a surface following scanner. However, implementation of Thermal Nondestructive Evaluations (TNDE) for flaw detection in composite materials and structures requires determining its limit. Advanced algorithms have been developed to enable locating and sizing defects in carbon fiber reinforced plastic (CFRP). Thermal Tomography is a very promising method for visualizing the size and location of defects in materials such as CFRP. However, further investigations are required to determine its capabilities for inspection of thick composites. In present work we have studied influence of the anisotropy on the reconstructed image of a defect generated by an inversion technique. The composite material is considered as homogeneous with macro properties: thermal conductivity K, specific heat c, and density rho. The simulation process involves two sequential steps: solving the three dimensional transient heat diffusion equation for a sample with a defect, then estimating the defect location and size from the surface spatial and temporal thermal distributions (inverse problem), calculated from the simulations.
Plotnikov, Y. A.; Winfree, W. P.
AMS Composite GOES Image Viewer and Data Lister
NSDL National Science Digital Library
The American Meteorological Society (AMS) Composite Geostationary Operational Environmental Satellite (GOES) Image Viewer and Data Lister is a small Java applet composite infrared (IR) image viewer that uses a near real-time composite infrared satellite picture of the U.S. to interactively explore the temperature as seen from space. The images are created every three hours from GOES-east and GOES-west by the McIDAS system. The composite IR image allows you to move the mouse pointer over the image while the temperature (degrees C), latitude and longitude are listed.
Whittaker, Tom
NASA Astrophysics Data System (ADS)
The speed at which our world is changing is reflected in the shifting way artistic images are created and produced. Holography can be used as a medium to express the perception of space with light and colour and to make the material and the immaterial experiments with optical and digital holography. This paper intends to be a reflection on the final product of that process surrounding a debate of ideas for new experimental methodologies applied to holographic images. Holography is a time-based medium and the irretrievable linear flow of time is responsible for a drama, unique to traditional cinematography. If the viewers move to left or right, they see glimpses of the next scene or the previous one perceived a second ago. This interaction of synthetic space arises questions such as: can we see, in "reality", two forms in the same space? Trying to answer this question, a series of works has been created. These concepts are embryonic to a series of digital art holograms and lenticulars technique's titled "Across Light: Through Colour". They required some technical research and comparison between effects from different camera types, using Canon IS3 and Sony HDR CX105.
Azevedo, Isabel; Richardson, Martin; Bernardo, Luis Miguel
Effects of dietary oregano and garlic essential oils on carcass characteristics, meat composition, colour, pH and sensory quality of broiler meat.
Abstract 1. An experiment was conducted to determine the individual and combined effects of two essential oils, oregano and garlic, on carcass characteristics, meat composition, colour, pH and sensory quality of broiler meat. 2. The diets were supplemented with no essential oil (control), oregano essential oil or garlic essential oil at 300�mg/kg and oregano essential oil at 150�mg/kg�+�garlic essential oil at 150�mg/kg. 3. Dietary oregano and garlic oil supplementation did not affect carcass yields, the relative weight of carcass parts, breast and thigh meat composition, pH or b* value of breast meat. Oregano�+�garlic oil supplementation significantly decreased the L* value. The a* value of breast meat in birds given a diet supplemented with oregano oil was lower than that in birds given a diet supplemented with garlic oil and oregano oil�+�garlic oil. The essential oil addition had no positive effect on the oxidative stability. There was no difference between the treatments in breast appearance. 4. The juiciness, flavour, oxidised flavour and acceptability of breast meat samples were affected by treatments. PMID:24404997
Kirkpinar, F; Unl�, H B; Serdaro?lu, M; Turp, G Y
Colour Vision and Colour Vision Theories
IN a recent letter to NATURE (September 29, p. 473) Dr. Edridge-Green has condemned the colour theory of Young and Helmholtz by the sweeping statement: ``There is no fact that directly supports the trichromatic theory.'' It is scarcely credible that such men of science as Young, Helmholtz, Maxwell, and Abney could have deliberately adopted a theory of colour vision with
Frank Allen
PixelFlow: high-speed rendering using image composition
We describe PixelFlow, an architecture for high-speed image generation that overcomes the transformation- and frame-buffer- access bottlenecks of conventional hardware rendering architec- tures. PixelFlow uses the technique of image composition : it distributes the rendering task over an array of identical renderers, each of which computes a full-screen image of a fraction of the primitives. A high-performa nce image-composition network
Steven Molnar; John G. Eyles; John Poulton
Stability of memory for colour in context.
Memory for colours presented in isolation was compared with that for colours presented as part of a clip-art image or as part of a non-meaningful, Mondrian-like image. The area under the Receiver Operating Characteristic for deciding that two colours, presented at different delay intervals, were the same or different provided an index of memory for colour. The provision of a context reduced the decay of memory, regardless of whether the context was meaningful (clip-art images) or non-meaningful (Mondrian-like images). The result was seen as a generalisation of the auditory phenomenon of profile analysis, in which memory for the amplitude of a single component of a complex sound is more stable than that for the component in isolation. PMID:10320866
Francis, M A; Irwin, R J
Advanced colour matching theory
Traditionally, computer colour matching systems have employed the Kubelka-Munk algorithms. This approach makes many assumptions which do not hold true when colour matching in non-hiding applications such as printing inks, plastics and woodstains. A many flux mathematical model has been proven to give accurate colour matches across all regions of optical density. The GretagMacbeth ProPalette� colour matching software employs this
Colin Wakeford
Imaging biopsy composition at ACL reconstruction
Purpose Early-stage osteoarthritis (OA) includes glycosaminoglycan (GAG) loss and collagen disruption that cannot be seen on morphological magnetic resonance imaging (MRI). T1? MRI is a measurement that probes the low-frequency rate of exchange between protons of free water and those from water associated with macromolecules in the cartilage�s extracellular matrix. While it has been hypothesized that increased water mobility resulting from early osteoarthritic changes cause elevated T1? MRI values, there remain several unknown mechanisms influencing T1? measurements in cartilage. The purpose of this work was to relate histological and biochemical metrics directly measured from osteochondral biopsies and fluid specimens with quantitative MRI-detected changes of in vivo cartilage composition. Patients and methods Six young patients were enrolled an average of 41 days after acute anterior cruciate ligament (ACL) rupture. Femoral trochlear groove osteochondral biopsies, serum, and synovial fluid were harvested during ACL reconstruction to complement a presurgery quantitative MRI study (T1?, T2, delayed gadolinium-enhanced MRI of cartilage [dGEMRIC] relaxation times). A high-resolution MRI scan of the excised osteochondral biopsy was also collected. Analyses of in vivo T1? images were compared with ex vivo T1? imaging, GAG assays and histological GAG distribution in the osteochondral biopsies, and direct measures of bone and cartilage turnover markers and �OA marker� 3B3 in serum and synovial fluid samples. Conclusion T1? relaxation times in patients with a torn ACL were elevated from normal, indicating changes consistent with general fluid effusion after blunt joint trauma. Increased chondrogenic progenitor cell (CPC) production of chondroprotective lubricin may relate to cartilage surface disruption by blunt trauma and CPC amplification of joint inflammation. Disparity between ex vivo and matched in vivo MRI of trochlear cartilage suggests MRI signal differences that may be related to the synovial fluid environment. T1? is emerging as a promising MRI biomarker to relate noninvasive measures of whole-joint condition and cartilage composition to direct measures of cartilage changes in the acute phase of joint injuries.
Pedersen, Douglas R; Martin, James A; Thedens, Daniel R; Klocke, Noelle F; Roberts, Nathaniel H; Goetz, Jessica E; Amendola, Annunziato
Cognition factors in colour identification of colour blind people
Cognition of colour blind people differs significantly from colour normal observers especially in their colour identification and discrimination. Dichromats lacking one of the three cone photoreceptor types identify less colours and have a general confusion determining colour terms. Our research was aimed to reveal several aspects of their colour cognition with newly developed methodologies and diagnostic equipment. Among other features
Gyorgy Abraham; Balazs V. Nagy
The world as perceived by human beings is full of colour. The world as described by physical scientists is composed of colourless particles and fields. Philosophical theories of colour since the scientific revolution have been primarily driven by a desire to harmonize these two apparently conflicting pictures of the world. Any adequate theory of colour has to be consistent with
David R. Hilbert
GIS-based colour composites and overlays to delineate heavy metal contamination zones in the shallow alluvial aquifers, Ankaleshwar industrial estate, south Gujarat, India
NASA Astrophysics Data System (ADS)
In an attempt to delineate heavy metal contamination precincts and to evaluate the extent and degree of toxic levels, besides their possible sources, 38 water samples from Ankaleshwar Industrial Estate, south Gujarat, India were analyzed. By clutching geochemical analyses and GIS-based colour composites areas depicting anomalously high concentration of heavy metals (Mo, Zn, Pb, Ni, Co, Cd, etc.) in the groundwater were revealed. The multicomponent overlays in grey-scale facilitated in identifying situates of heavy metal �hot spots�, and lateral protuberances of the contamination plume around defile stretch of the main stream Amla Khadi flowing through the area. The multiple pollution plumes emerging from other parts of the area further coincide with effluent laden streams and small channels indicating industrial establishments as major sources of groundwater contamination. Influent nature of the streams, accelerated infiltration process, high mass influx and shallow groundwater table are the factors conducive for easy access of heavy metals to the phreatic aquifers affecting over 20 km2 area. On the basis of P/ U ratios (concentration of metals in polluted water to unpolluted water), geogenic and anthropogenic sources have been identified. Very high levels of technogenic elements present in the ground water raise concerns about possible migration into food crops, as the area is an important horticultural locale and is highly cultivated.
Kumar, Suyash; Shirke, K. D.; Pawar, N. J.
Perception of age in adult Caucasian male faces: computer graphic manipulation of shape and colour information.
This study investigated visual cues to age by using facial composites which blend shape and colour information from multiple faces. Baseline measurements showed that perceived age of adult male faces is on average an accurate index of their chronological age over the age range 20-60 years. Composite images were made from multiple images of different faces by averaging face shape and then blending red, green and blue intensity (RGB colour) across comparable pixels. The perceived age of these composite or blended images depended on the age bracket of the component faces. Blended faces were, however, rated younger than their component faces, a trend that became more marked with increased component age. The techniques used provide an empirical definition of facial changes with age that are biologically consistent across a sample population. The perceived age of a blend of old faces was increased by exaggerating the RGB colour differences of each pixel relative to a blend of young faces. This effect on perceived age was not attributable to enhanced contrast or colour saturation. Age-related visual cues defined from the differences between blends of young and old faces were applied to individual faces. These transformations increased perceived age. PMID:7732035
Burt, D M; Perrett, D I
SLIC: Scheduled Linear Image Compositing for Parallel Volume Rendering
Parallel volume rendering offers a feasible solution to the large data visualization problem by distributing both the data and rendering calculations among multiple computers connected by a network. In sort-last parallel volume rendering, each processor generates an image of its assigned subvolume, which is blended together with other images to derive the final image. Improving the efficiency of this compositing
Aleksander Stompel; Kwan-Liu Ma; Eric B. Lum; James P. Ahrens; John Patchett
The functional anatomy of imagining and perceiving colour.
We report two functional magnetic resonance imaging experiments which reveal similarities and differences between perceptual and imaginal networks within the single visual submodality of colour. The first experiment contrasted viewing of a coloured and grey-scale Mondrian display, while the second contrasted a relative colour judgement with a spatial task and required the generation of mental images. Our results show that colour perception activates the posterior fusiform gyrus bilaterally (area V4), plus right-sided anterior fusiform and lingual gyri, striate cortex (area V1), and the left and right insula. Colour imagery activated right anterior fusiform gyrus, left insula, right hippocampus and parahippocampal gyrus, but not V4 or V1. The findings reconcile neurological case studies suggesting a double dissociation between deficits in colour imagery and perception and point to anterior fusiform, parahippocampal gyri and hippocampus as the location for stored representations of coloured objects. PMID:9601660
Howard, R J; ffytche, D H; Barnes, J; McKeefry, D; Ha, Y; Woodruff, P W; Bullmore, E T; Simmons, A; Williams, S C; David, A S; Brammer, M
Multiclass detection of cells in multicontrast composite images.
In this paper, we describe a framework for multiclass cell detection in composite images consisting of images obtained with three different contrast methods for transmitted light illumination (referred to as multicontrast composite images). Compared to previous multiclass cell detection results [1], the use of multicontrast composite images was found to improve the detection accuracy by introducing more discriminatory information into the system. Preprocessing multicontrast composite images with Kernel PCA was found to be superior to traditional linear PCA preprocessing, especially in difficult classification scenarios where high-order nonlinear correlations are expected to be important. Systematic study of our approach under different overlap conditions suggests that it possesses sufficient speed and accuracy for use in some practical systems. PMID:20022596
Long, Xi; Cleveland, W Louis; Yao, Y Lawrence
Colour constancy as counterfactual
There is nothing in this World constant but Inconstancy.[Swift 1711: 258]In this paper I argue that two standard characterizations of colour constancy are inadequate to the phenomenon. This inadequacy matters, since, I contend, philosophical appeals to colour constancy as a way of motivating illumination-independent conceptions of colour turn crucially on the shortcomings of these characterizations. After critically reviewing the standard
Jonathan Cohen
Configural and featural information in facial-composite images.
Eyewitnesses are often invited to construct a facial composite, an image created of the person they saw commit a crime that is used by law enforcement to locate criminal suspects. In the current paper, the effectiveness of composite images was investigated from traditional feature systems (E-FIT and PRO-fit), where participants (face constructors) selected individual features to build the face, and a more recent holistic system (EvoFIT), where they 'evolved' a composite by repeatedly selecting from arrays of complete faces. Further participants attempted to name these composites when seen as an unaltered image, or when blurred, rotated, linearly stretched or converted to a photographic negative. All of the manipulations tested reduced correct naming of the composites overall except (i) for a low level of blur, for which naming improved for holistic composites but reduced for feature composites, and (ii) for 100% linear stretch, for which a substantial naming advantage was observed. Results also indicated that both featural (facial elements) and configural (feature spacing) information were useful for recognition in both types of composite system, but highly-detailed information was more accurate in the feature-based than in the holistic method. The naming advantage of linear stretch was replicated using a forensically more-practical procedure with observers viewing an unaltered composite sideways. The work is valuable to police practitioners and designers of facial-composite systems. PMID:24796951
Frowd, Charlie D; Jones, Sharrome; Fodarella, Cristina; Skelton, Faye; Fields, Steve; Williams, Anna; Marsh, John E; Thorley, Rachel; Nelson, Laura; Greenwood, Leah; Date, Louisa; Kearley, Kevin; McIntyre, Alex H; Hancock, Peter J B
Colour knowledge: the role of the right hemisphere in colour processing and object colour knowledge.
The lateralisation of colour processing is not well understood, although there is a reasonable amount of evidence indicating a right hemisphere bias for colour processing. Tasks that require colour naming are associated with a left hemisphere bias and it is likely that asymmetry of colour processing is influenced by task demands. It is not known whether object colour knowledge is lateralised. In the current study colour and achromatic Mondrian-like objects were presented to either the left or right hemisphere to assess the lateralisation of colour processing. Participants were required to judge whether the objects were colour or achromatic. To assess colour knowledge, congruently and incongruently coloured familiar objects were presented to either the left or right hemisphere and participants were required to judge whether the objects were correctly or incorrectly coloured. The data show that both colour processing and colour knowledge are associated with a right hemisphere bias. PMID:18608853
Barnett, Kylie J
Modified Global and Modified Linear Contrast Stretching Algorithms: New Colour Contrast Enhancement Techniques for Microscopic Analysis of Malaria Slide Images
Malaria is one of the serious global health problem, causing widespread sufferings and deaths in various parts of the world. With the large number of cases diagnosed over the year, early detection and accurate diagnosis which facilitates prompt treatment is an essential requirement to control malaria. For centuries now, manual microscopic examination of blood slide remains the gold standard for malaria diagnosis. However, low contrast of the malaria and variable smears quality are some factors that may influence the accuracy of interpretation by microbiologists. In order to reduce this problem, this paper aims to investigate the performance of the proposed contrast enhancement techniques namely, modified global and modified linear contrast stretching as well as the conventional global and linear contrast stretching that have been applied on malaria images of P. vivax species. The results show that the proposed modified global and modified linear contrast stretching techniques have successfully increased the contrast of the parasites and the infected red blood cells compared to the conventional global and linear contrast stretching. Hence, the resultant images would become useful to microbiologists for identification of various stages and species of malaria.
Abdul-Nasir, Aimi Salihah; Mashor, Mohd Yusoff; Mohamed, Zeehaida
Colour Vision and Colour Vision Theories
IN the first of my two recent letters on this subject I selected five of the cases in which Dr. Edridge-Green asserts that the trichromatic theory cannot explain certain phenomena of colour vision; and I indicated, in each case, the source of his error. In more than one case I gave the full proof. In his reply he took no
W. Peddie
Colour Vision and Colour Vision Theories
PROF. PEDDIE, in NATURE of August 4, p. 163, has dealt with some of my strictures of the trichromatic theory. Whilst nothing can be said against his mathematical presentation of the theory, it can easily be shown that, when a case of colour blindness is fully and carefully examined, the mathematical presentation will not account for the facts. All the
F. W. Edridge-Green
[Optic mixing of colours in Seurat's painting].
Georges Seurat is the initiator and master of the divisionism. He founds the neoimpressionism current that tries to reproduce the nature exclusively through coloured vibration. Seurat applies the colours in small touches uniformly distributed on the canvas; the colours merge if they are looked by a certain distance, through optical interference. When the spectator approaches from the picture, the special frequency decreases, the optical merging does not appear and the onlooker looks a lot of coloured spots. When the spectator moves away from the picture, the optical interference appears and the clarity of the image becomes perfectly. This current opened the way of the future's modern painting performed by C�zanne, Renoir, Van Gogh. PMID:12677811
Cernea, Paul
Effects of memory colour on colour constancy for unknown coloured objects
The perception of an object's colour remains constant despite large variations in the chromaticity of the illumination�colour constancy. Hering suggested that memory colours, the typical colours of objects, could help in estimating the illuminant's colour and therefore be an important factor in establishing colour constancy. Here we test whether the presence of objects with diagnostical colours (fruits, vegetables, etc) within a scene influence colour constancy for unknown coloured objects in the scene. Subjects matched one of four Munsell papers placed in a scene illuminated under either a reddish or a greenish lamp with the Munsell book of colour illuminated by a neutral lamp. The Munsell papers were embedded in four different scenes�one scene containing diagnostically coloured objects, one scene containing incongruent coloured objects, a third scene with geometrical objects of the same colour as the diagnostically coloured objects, and one scene containing non-diagnostically coloured objects (eg, a yellow coffee mug). All objects were placed against a black background. Colour constancy was on average significantly higher for the scene containing the diagnostically coloured objects compared with the other scenes tested. We conclude that the colours of familiar objects help in obtaining colour constancy for unknown objects.
Granzier, Jeroen J M; Gegenfurtner, Karl R
NASA Astrophysics Data System (ADS)
For better image interpretation and analysis, an algorithm for producing a Multi-Feature Composite moving image (termed "MFC image") inducing visual illusion (i.e., pseudo-rotational and persistent of vision) has been newly developed. The animation-like MFC image is produced by continuously displaying emboss processing-based images (i.e., shade images) according to the eight directions of light sources. In this study, the effectiveness in case of overlaying the different kinds of image texture features (e.g., contrast, entropy, energy, mean, laplacian, variance, etc.) on the shade images has been investigated. Through the quantitative- and qualitative-analysis for MFC images, we have confirmed the proposed algorithm to produce MFC image is useful for simultaneously enhancing image features as well as for maintaining the quality of original image itself.
Hirota, Kenichi; Ninomiya, Tatsuru; Kojima, Hirohito; Ohwada, Hayato
Object knowledge modulates colour appearance
We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis.
Witzel, Christoph; Valkova, Hanna; Hansen, Thorsten; Gegenfurtner, Karl R
The connotations of colour terms: colour based X-phemisms
This paper investigates the connotations of colour terms with particular attention to figurative uses of black, white, grey, brown, yellow, red, green, blue and a few miscellaneous colours. The connotations are judged on the basis of whether the phrases in which the colour terms occur are typically orthophemistic, euphemistic, or dysphemistic. All the colours surveyed have some, often many, orthophemistic
Keith Allan
Imaging with lithium niobate\\/epoxy composites
Lithium niobate, LiNbO3, is a very promising material for high temperature applications in non-destructive testing because of its high Curie temperature. However, for commercial applications LiNbO3 has often been neglected because of its low electromechanical coupling coefficients. This paper explores the potential of LiNbO3 composites, by means of room temperature characterization and measurements, for further use in operation in high
N. Schmarje; J. F. Saillant; K. J. Kirk; S. Cochran
Adaptive plasticity during the development of colour vision
Colour vision greatly enhances the discriminatory and cognitive capabilities of visual systems and is found in a great majority of vertebrates and many invertebrates. However, colour coding visual systems are confronted with the fact that the external stimuli are ambiguous because they are subject to constant variations of luminance and spectral composition. Furthermore, the transmittance of the ocular media, the
Hans-Joachim Wagner; Ronald H. H. Kr�ger
Document Image Processing: Going beyond the Black-and-White Barrier. Progress, Issues and Options with Greyscale and Colour Image Processing.
ERIC Educational Resources Information Center
Discussion of digital document image processing focuses on issues and options associated with greyscale and color image processing. Topics include speed; size of original document; scanning resolution; markets for different categories of scanners, including photographic libraries, publishing, and office applications; hybrid systems; data�
Hendley, Tom
Automatic photobook: focusing on image selection and image layout based on content and composition
NASA Astrophysics Data System (ADS)
In this paper, we present improvements to image selection and image layout for automatic photobook generating algorithms. These improvements are designed to help the user easily create a photo album, which matches the user preferences and strengthens the aesthetic quality of the photobook. Image content, composition, and metadata are utilized to determine the set of images being selected, and to suggest the layout of each page.
Xue, Shao-Fu; Tang, Henry; Tretter, Daniel; Lin, Qian; Allebach, Jan
BackgroundThe perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour) appear brighter than stimuli that are less saturated at
David Corney; John-Dylan Haynes; Geraint Rees; R. Beau Lotto; Olaf Sporns
Colour Mixing Based on Daylight
ERIC Educational Resources Information Center
Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large�
Meyn, Jan-Peter
NASA Astrophysics Data System (ADS)
We derive colour spaces of the hue-colourfulness-luminance type, on the basis of a four-dimensional hypercube I4 (I = [0, 1]). The hypercube corresponds to a tetrachromatic colour system, analogous to the three-dimensional RGB cube. In the first derived space the colourfulness is chromatic saturation while in the second one, colourfulness refers to the vividness of the colour, even if it is achromatic. The hue is defined on the basis of an icositetrahedron of 24 triangles that is embedded in the boundary of the hypercube. The boundary of the hypercube is the polytope {4 3 3} (in Sclafli notation) that is a topological 3-sphere. Out of the 24 square faces in the boundary of the hypercube, 6 meet the black vertex and 6 meet the white vertex; the remaining 12 faces form a dodecahedron which is a topological 2-sphere. This equatorial or chromatic dodecahedron is used to define a hue for each point in the hypercube that is not on the achromatic segment; the icositetrahedron results from a division of each of the square faces of the dodecahedron into two triangles. In addition, a hexdecahedron of 16 square faces with the topology of a torus that is also embedded in the boundary of the hypercube, is used to define an alternate two-dimensional hue space.
Restrepo, Alfredo
A flexible processor architecture for MPEG4 image compositing
This paper proposes a new array architecture for MPEG-4 image compositing. The emerging MPEG4 standard for multimedia applications allows script-based compositing of audiovisual scenes from multiple audio and visual objects. MPEG-4 supports both, natural (video) and synthetic (3D) visual objects or a combination of both. Objects can be manipulated, e.g. positioned, rotated, warped or duplicated by user interaction. A coprocessor
M. Berekovic; R. Frase; P. Pirsch
Compositional breast imaging using a dual-energy mammography protocol
Purpose: Mammography has a low sensitivity in dense breasts due to low contrast between malignant and normal tissue confounded by the predominant water density of the breast. Water is found in both adipose and fibroglandular tissue and constitutes most of the mass of a breast. However, significant protein mass is mainly found in the fibroglandular tissue where most cancers originate. If the protein compartment in a mammogram could be imaged without the influence of water, the sensitivity and specificity of the mammogram may be improved. This article describes a novel approach to dual-energy mammography, full-field digital compositional mammography (FFDCM), which can independently image the three compositional components of breast tissue: water, lipid, and protein. Methods: Dual-energy attenuation and breast shape measures are used together to solve for the three compositional thicknesses. Dual-energy measurements were performed on breast-mimicking phantoms using a full-field digital mammography unit. The phantoms were made of materials shown to have similar x-ray attenuation properties of the compositional compartments. They were made of two main stacks of thicknesses around 2 and 4 cm. Twenty-six thickness and composition combinations were used to derive the compositional calibration using a least-squares fitting approach. Results: Very high accuracy was achieved with a simple cubic fitting function with root mean square errors of 0.023, 0.011, and 0.012 cm for the water, lipid, and protein thicknesses, respectively. The repeatability (percent coefficient of variation) of these measures was tested using sequential images and was found to be 0.5%, 0.5%, and 3.3% for water, lipid, and protein, respectively. However, swapping the location of the two stacks of the phantom on the imaging plate introduced further errors showing the need for more complete system uniformity corrections. Finally, a preliminary breast image is presented of each of the compositional compartments separately. Conclusions: FFDCM has been derived and exhibited good compositional thickness accuracy on phantoms. Preliminary breast images demonstrated the feasibility of creating individual compositional diagnostic images in a clinical environment.
Laidevant, Aurelie D.; Malkov, Serghei; Flowers, Chris I.; Kerlikowske, Karla; Shepherd, John A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94143 (United States); Department of Medicine and Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94143 (United States); Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94143 (United States)
Magnetic resonance imaging of gel-cast ceramic composites
Magnetic resonance imaging (MRI) techniques are being employed to aid in the development of advanced near-net-shape gel-cast ceramic composites. MRI is a unique nondestructive evaluation tool that provides information on both the chemical and physical properties of materials. In this effort, MRI imaging was performed to monitor the drying of porous green-state alumina - methacrylamide-N.N`-methylene bisacrylamide (MAM-MBAM) polymerized composite specimens. Studies were performed on several specimens as a function of humidity and time. The mass and shrinkage of the specimens were also monitored and correlated with the water content.
Dieckman, S.L.; Balss, K.M.; Waterfield, L.G. [and others
Chemical imaging of wood-polypropylene composites.
Recent investigations of wood plastic composites have revealed a detrimental effect of using lubricant systems in production. This includes nullifying part or all of the mechanical benefit of using a polar compatibilizer, maleic anhydride polypropylene (MAPP), in the composite formulation. This investigation utilizes lubricants labeled with deuterium in conjunction with Fourier transform infrared (FT-IR) spectroscopy to allow for the separation of individual lubricants from all other material constituents. All of the deuterium labeled lubricants, used without MAPP, revealed their expulsion from the wood interface during crystallization. MAPP coupling agent was found to exist near the wood, but it is unclear if any covalent bonding with the hydroxyl functionality on the wood surface occurred. The addition of zinc stearate lubricants appears to nullify the activity of the anhydride functionality near the wood surface as evidenced by a shift in the FT-IR spectra to the hydrolyzed form of the coupling agent. Most of the additives collect at the edges of the spherulites in mostly amorphous regions of the material. The consequence of this morphology may be a weak interface between crystallites. PMID:16925926
Harper, David P; Wolcott, Michael P
Prostate Mechanical Imaging: 3-D Image Composition and Feature Calculations
We have developed a method and a device entitled prostate mechanical imager (PMI) for the real-time imaging of prostate using a transrectal probe equipped with a pressure sensor array and position tracking sensor. PMI operation is based on measurement of the stress pattern on the rectal wall when the probe is pressed against the prostate. Temporal and spatial changes in the stress pattern provide information on the elastic structure of the gland and allow two-dimensional (2-D) and three-dimensional (3-D) reconstruction of prostate anatomy and assessment of prostate mechanical properties. The data acquired allow the calculation of prostate features such as size, shape, nodularity, consistency/hardness, and mobility. The PMI prototype has been validated in laboratory experiments on prostate phantoms and in a clinical study. The results obtained on model systems and in vivo images from patients prove that PMI has potential to become a diagnostic tool that could largely supplant DRE through its higher sensitivity, quantitative record storage, ease-of-use and inherent low cost.
Egorov, Vladimir; Ayrapetyan, Suren; Sarvazyan, Armen P.
Shadow And Highlight Invariant Colour Segmentation Algorithm For Traffic Signs
Shadows and highlights represent a challenge to the computer vision researchers due to a variance in the brightness on the surfaces of the objects under consideration. This paper presents a new colour detection and segmentation algorithm for road signs in which the effect of shadows and highlights are neglected to get better colour segmentation results. Images are taken by a
Hasan Fleyeh
Simple and Robust Optic Disc Localisation Using Colour Decorrelated Templates
Automatic analysis of digital fundus images, where optic disc extraction is an essential part, is an active research topic\\u000a in retinal image analysis. A simple, fast and robust optic disc localisation method using colour decorrelated templates is\\u000a proposed which results an accurate location of the optic disc in colour fundus images. In the training stage, PCA is performed\\u000a on the
Tomi Kauppi; Heikki K�lvi�inen
Multisource Composite Kernels for Urban-Image Classification
This letter presents advanced classification methods for very high resolution images. Efficient multisource information, both spectral and spatial, is exploited through the use of composite kernels in support vector machines. Weighted summations of kernels accounting for separate sources of spectral and spatial information are analyzed and compared to classical approaches such as pure spectral classification or stacked approaches using all
Devis Tuia; Fr�d�ric Ratle; Alexei Pozdnoukhov; Gustavo Camps-Valls
Characterization of Fiber Composite Flywheels by Ultrasonic Imaging Techniques.
National Technical Information Service (NTIS)
A set of flywheels of different fiber composites has been investigated ultrasonically by an ULTRA IMAGE III System developed by General Dynamics. The 40 cm (16 in.) in diameter and 4.3 cm (1.7 in.) thick flywheels have been studied in an immersion test wi...
M. C. Tsao R. H. Grills G. A. Andrew A. P. Coppa
A New Paradigm in Image Indexing and Retrieval Using Composite Bitplane Signatures
A scheme based on bitplane signatures for fast image searching is presented. It makes use of composite bitplanes obtained from overlaying bitplane signatures to form composite bitplane signatures. For large image databases, a hierarchical structure of composite bitplane signatures can be used to provide ranked images without the need to compare and traverse all the images in the database, as
Simon So; Clement H. C. Leung
Iris Recognition System Using Combined Colour Statistics
This paper proposes a high performance iris recognition system based on the probability distribution functions (PDF) of pixels in different colour channels. The PDFs of the segmented iris images are used as statistical feature vectors for the recognition of irises by minimizing the Kullback-Leibler distance (KLD) between the PDF of a given iris and the PDFs of irises in the
Hasan Demirel; G. Anbarjafari
Shape and colour measurement of colourful objects by fringe projection
NASA Astrophysics Data System (ADS)
In this paper, we present a novel method to measure shape and colour information of a colourful object by projecting separate red, green and blue colour fringe patterns onto the object surface. With regard to the object surface's colour, the modulation at each pixel position in the three colour channels has different values. For example, when projecting blue fringe patterns onto a red point, the corresponding pixel has too low a fringe modulation to accurately calculate the phase (shape) information; but with red fringe patterns a high fringe modulation is obtained. Therefore, phase information of the red point can be calculated by projecting red fringe patterns. For each object point, by comparing the modulation values from the three colour channels, it is possible to choose the channel having maximum modulation, and hence phase information can be reliably obtained by the phase-shifting algorithm. The fringe order information is obtained by using the optimum three-frequency selection method, so there is a maximum reliability in determining the fringe order and the 3-D shape of an object with step or large slopes on the surface. Since three colour channels are used, colour information of the object surface can be extracted with high dynamic range from the same fringe patterns. Chromatic aberration between colour channels is unavoidable and can be eliminated by a software-based method. Using the recently developed colour fringe projection system, separate colour fringe patterns are projected onto a mug having different colour patterns, a colourful box and plate, and a colour checker card to test the proposed method. The results show the range of colours that can be measured and that shape and colour information of colourful objects can be reliably obtained.
Zhang, Zonghua; Towers, Catherine E.; Towers, David P.
Thin-film, flat-panel, composite imagers for projection and tomographic imaging
The recent development of large-area, flat-panel a-Si:H imaging arrays is generally expected to lead to real-time diagnostic and megavoltage x-ray projection imagers with film-cassette-like profiles. While such flat-panel imagers offer numerous advantages over existing fluoroscopic and radiographic imaging devices, the unique properties of the arrays also offer the prospect of detector configuration not previously possible with other real-time technologies. the thin, highly uniform profile of the arrays allows the creation of composite imaging devices in which a flat-panel detector overlies a second imaging detector. A dual-energy (diagnostic and megavoltage) composite imager consisting of a pair of stacked, flat-panel imagers would provide unique information helping to resolve the patient localization and verification problem in megavoltage radiotherapy. In PET or SPECT, attenuation corrections could be obtained by placing a flat-panel array for transmission measurements directly in front of the main emission detector. In this article, the concept of such real-time flat-panel composite imagers is proposed. Specific embodiments of this concept applied toward the resolution of outstanding problems in radiotherapy, PET and SPECT are outlined and calculations and data supporting the feasibility of the concept are presented.
Antonuk, L.E.; Boudry, J.; Huang, W.; Lam, K.L.; Ten Haken, R.K.; Yorkston, J.; Clinthorne, N.H. (Univ. of Michigan Medical Center, Ann Arbor, MI (United States)); Morton, E.J. (Univ. of Surrey, Guilford (United Kingdom))
Photolithography is a crucial technology for both research and industry. The desire to be able to create ever finer features has fuelled a push towards lithographic methods that use electromagnetic radiation or charged particles with the shortest possible wavelength. At the same time, the physics and chemistry involved in employing light or particles with short wavelengths present great challenges. A new class of approaches to photolithography on the nanoscale involves the use of photoresists that can be activated with one colour of visible or near-ultraviolet light and deactivated with a second colour. Such methods hold the promise of attaining lithographic resolution that rivals or even exceeds that currently sought by industry, while at the same time using wavelengths of light that are inexpensive to produce and can be manipulated readily. The physical chemistry of 2-colour photolithography is a rich area of science that is only now beginning to be explored. PMID:24705478
Fourkas, John T; Petersen, John S
Genetic analyses of the human eye colours using a novel objective method for eye colour classification.
In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p<10(-6)) in the PIE-scores of the individuals typed as HERC2 rs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of the DIAT software and the PIE-score, it will be possible to automatically compare the iris colour of large numbers of iris images obtained by different studies and to perform large meta-studies that may reveal loci with small effects on the eye colour. PMID:23948321
Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; S�rensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; B�rsting, Claus; Morling, Niels
Why birds eat colourful grit: colour preferences revealed by the colour of gizzard stones.
Colour preferences from sexual or social contexts are assumed to have arisen owing to preferences for specific kinds of food, representing a sensory bias, but once colour preferences have evolved in a sexual context, they may also be expressed during foraging. We tested whether preferences for specific body colours (i.e. plumage and soft parts) were related to colour preferences for grit ingested by birds. Birds eat grit to facilitate break down of food by the gizzard, and this function is independent of the colour of grit, but depends on the physical properties of stones. Bird species were significantly consistent in colour of grit, and grit of different colours varied in prevalence among species, even when analyses were restricted to a sample from a single locality. There were positive correlations between presence of lilac and red grit in the gizzard and presence of sexually dichromatic lilac and red colour on the body. There was a positive correlation between red grit colour and red sexually monochromatic body colour. Bird species with many different sexual colours, but not sexually monochromatic colours on their body had many different colours of grit. Males had more lilac and red grit than females, with this effect differing among species, whereas that was not the case for grit of other colours. These findings are consistent with the sensory bias hypothesis that birds express preferences for grit of specific colours and a high diversity of colours related to sexual colouration of the body, even when the colour of such grit is only visible to the individual at the moment of ingestion. PMID:20050966
M�ller, A P; Erritz�e, J
Spatio-temporal colour correction of strongly degraded movies
NASA Astrophysics Data System (ADS)
The archives of motion pictures represent an important part of precious cultural heritage. Unfortunately, these cinematography collections are vulnerable to different distortions such as colour fading which is beyond the capability of photochemical restoration process. Spatial colour algorithms-Retinex and ACE provide helpful tool in restoring strongly degraded colour films but, there are some challenges associated with these algorithms. We present an automatic colour correction technique for digital colour restoration of strongly degraded movie material. The method is based upon the existing STRESS algorithm. In order to cope with the problem of highly correlated colour channels, we implemented a preprocessing step in which saturation enhancement is performed in a PCA space. Spatial colour algorithms tend to emphasize all details in the images, including dust and scratches. Surprisingly, we found that the presence of these defects does not affect the behaviour of the colour correction algorithm. Although the STRESS algorithm is already in itself more efficient than traditional spatial colour algorithms, it is still computationally expensive. To speed it up further, we went beyond the spatial domain of the frames and extended the algorithm to the temporal domain. This way, we were able to achieve an 80 percent reduction of the computational time compared to processing every single frame individually. We performed two user experiments and found that the visual quality of the resulting frames was significantly better than with existing methods. Thus, our method outperforms the existing ones in terms of both visual quality and computational efficiency.
Islam, A. B. M. Tariqul; Farup, Ivar
We present a survey of results from various research groups under the unifying viewpoint of transformational physics, which has been recently introduced for the design of metamaterials in optics and acoustics. We illustrate the versatility of underlying geometric transforms in order to bridge wave phenomena (the different 'colours' of waves) ranging from transverse electric waves, to linear surface water waves
S�bastien Guenneau; Ross C. McPhedran; Stefan Enoch; Alexander B. Movchan; Mohamed Farhat; Nicolae-Alexandru P. Nicorovici
Colour-scent associations in a tropical orchid: three colours but two odours.
Colour and scent are the major pollinator attractants to flowers, and their production may be linked by shared biosynthetic pathways. Species with polymorphic floral traits are particularly relevant to study the joint evolution of floral traits. We used in this study the tropical orchid Calanthe sylvatica from R�union Island. Three distinct colour varieties are observed, presenting lilac, white or purple flowers, and named respectively C. sylvaticavar.lilacina (hereafter referred as var. lilacina), C. sylvaticavar. alba (var. alba) and C. sylvatica var. purpurea (var. purpurea). We investigated the composition of the floral scent produced by these colour varieties using the non-invasive SPME technique in the wild. Scent emissions are dominated by aromatic compounds. Nevertheless, the presence of the terpenoid (E)-4,8-dimethylnona-1,3,7-tri�ne (DMNT) is diagnostic of var. purpurea, with the volatile organic compounds (VOC) produced by some individuals containing up to 60% of DMNT. We evidence specific colour-scent associations in C. sylvatica, with two distinct scent profiles in the three colour varieties: the lilacina-like profile containing no or very little DMNT (<2%) and the purpurea-like profile containing DMNT (>2%). Calanthe sylvatica var. alba individuals group with one or the other scent profile independently of their population of origin. We suggest that white-flowered individuals have evolved at least twice, once from var. lilacina and at least once from var. purpurea after the colonisation of la R�union. White-flowered individuals may have been favoured by the particular pollinator fauna characterising the island. These flowering varieties of C. sylvatica, which display three colours but two scents profiles prove that colour is not always a good indicator of odour and that colour-scent associations may be complex, depending on pollination ecology of the populations concerned. PMID:21377705
Delle-Vedove, Roxane; Juillet, Nicolas; Bessi�re, Jean-Marie; Grison, Claude; Barthes, Nicolas; Pailler, Thierry; Dormont, Laurent; Schatz, Bertrand
We propose a colour tracker for use in visual surveillance. The tracker is part of a framework designed to monitor a dynamic scene with more than one camera. Colour tracking complements spatial tracking: it can also be used over large temporal intervals, and between spatially uncalibrated cameras. The colour distributions from objects are modelled, and measures of difference between them
J. Orwell; P. Remagnino; G. A. Jones
Colour thresholding and objective quantification in bioimaging.
Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples. PMID:1527795
Fermin, C D; Gerber, M A; Torre-Bueno, J R
Minimalist surface-colour matching.
Some theories of surface-colour perception assume that observers estimate the illuminant on a scene so that its effects can be discounted. A critical test of this interpretation of colour constancy is whether surface-colour matching is worse when the number of surfaces in a scene is so small that any illuminant estimate is unreliable. In the experiment reported here, observers made asymmetric colour matches between pairs of simultaneously presented Mondrian-like patterns under different daylights. The patterns had either 49 surfaces or a minimal 2 surfaces. No significant effect of number was found, suggesting that illuminant estimates are unnecessary for surface-colour matching. PMID:16178156
Amano, Kinjiro; Foster, David H; Nascimento, S�rgio M C
Minimalist surface-colour matching
Some theories of surface-colour perception assume that observers estimate the illuminant on a scene so that its effects can be discounted. A critical test of this interpretation of colour constancy is whether surface-colour matching is worse when the number of surfaces in a scene is so small that any illuminant estimate is unreliable. In the experiment reported here, observers made asymmetric colour matches between pairs of simultaneously presented Mondrian-like patterns under different daylights. The patterns had either 49 surfaces or a minimal 2 surfaces. No significant effect of number was found, suggesting that illuminant estimates are unnecessary for surface-colour matching.
Amano, Kinjiro; Foster, David H.; Nascimento, Sergio M C
Tests of commercial colour CMOS cameras for astronomical applications
NASA Astrophysics Data System (ADS)
We present some results of testing commercial colour CMOS cameras for astronomical applications. Colour CMOS sensors allow to perform photometry in three filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system realized in colour CMOS sensors is close to the astronomical Johnson BVR system. The basic camera characteristics: read noise (e^{-}/pix), thermal noise (e^{-}/pix/sec) and electronic gain (e^{-}/ADU) for the commercial digital camera Canon 5D MarkIII are presented. We give the same characteristics for the scientific high performance cooled CCD camera system ALTA E47. Comparing results for tests of Canon 5D MarkIII and CCD ALTA E47 show that present-day commercial colour CMOS cameras can seriously compete with the scientific CCD cameras in deep astronomical imaging.
Pokhvala, S. M.; Reshetnyk, V. M.; Zhilyaev, B. E.
The authors studies the phenomenological implications of the Chiral Colour model which allow him to derive experimental bounds on the axigluon mass or to predict deviations from the Standard Model. After a short introduction to the theory, the author examines the way it modifies the standard decay of quarkonium. Comparison with the observed lifetime of the upsilon allows him to exclude the existence of axigluons lighter than 9 GeV. (Others have since extended the work and were able to increase this limit to 25 GeV.) He then studies the Chiral Colour contribution to the hadronic cross-section in the electron-positron scattering and derive a conservative lower bound of 50 GeV for the axigluon mass. Finally, he predicts observable enhancements of the lifetime and rare decay channels of the Z{sup O} in the presence of light axigluons.
Cuypers, F.
This paper describes a Petri net model, called Coloured Petri nets (CP-nets), where information is attached to each token.\\u000a The information can be inspected and modified when a transition fires. For most applications, this generalization of ordinary\\u000a Petri nets allows the user to make more manageable descriptions, due to the fact that equal subnets can be folded into each\\u000a other,
Kurt Jensen
The development of artists' novel colour palettes for inkjet printing
NASA Astrophysics Data System (ADS)
In this changing environment in which the artist and designer has access to a wide range of digital imaging tools and technologies, that on first glance, are dedicated to the creation of colour mixtures, why is the digital interface and colour outcome often disappointing? It appears that hardware, software tools and methods for digital printing are not necessarily suited to the specific requirements of the artist. In fact, they are too generalised to obtain a high degree of quality and too inflexible to allow artists to obtain precision and predictability. Is it possible for an artist to mix and print a colour that captures their creative imagination? The motivation for this research is based on how artists mix and print colour by traditional means (painting and printmaking) and how these differ from colour picker tools, slider bars and methods developed for digital printing, and whether it is possible to incorporate both? The paper provides a brief historical background to artists who have developed colour systems to assist their particular colour choices. Based on existing hardware and software, the paper suggests alternative approaches to colour selection, demonstrates methods for the creation of novel inkjet printed palettes, and how these can be visualised and compared.
Parraman, Carinna
Simulation of ultrasonic array imaging of composite materials with defects.
Ultrasonic transducer arrays are extensively used for the nondestructive evaluation of materials for aerospace and other applications. However, their use with composites requires some technique development because of reflections at the layer boundaries and the effects of attenuation. When used in full matrix capture mode, algorithms such as the total focusing method (TFM) must be applied to obtain the image. In composite materials, improvement to the algorithm is required to include the effects of material anisotropy (affecting wave speed) and optimum aperture limits to optimize the signal-to-noise ratio and location detection for a defect in the material. This paper presents simulations of the ultrasonic array signals in multilayer anisotropic materials with and without a simulated defect. A kernel model for plane wave propagation in the material is combined with an angular spectrum decomposition (for finite transducer elements) and transducer frequency response, to model the full array signals. Inclusion of the defect is through its far-field scattering response. The model facilitates the study of imaging algorithm development by identification of the effects of anisotropy, signal-to-noise ratio, and aperture limit. An analytical method for the calculation of the effective group velocity in the composite at low frequency is demonstrated, permitting rapid calculation of time delay laws in practice. PMID:24658724
Humeida, Yousif; Pinfield, Valerie J; Challis, Richard E; Wilcox, Paul D; Li, Chuan
Composite delamination depth profiling in sonic-IR imaging
NASA Astrophysics Data System (ADS)
Impact damage remains a major issue for aerospace composite structures. Considerable internal damage can occur in laminated composites from external impact loads in service with only minimal visual detectability from the surface of the structure. Damage can occur at any ply depth without visual indications on the front surface. Accurate depth measurements can aid repair assessments. This method is focused on investigating depth profiling of composite delamination by using Sonic-IR, which is a nondestructive evaluation method (NDE) technique that makes images of defects using an infrared camera with an ultrasonic transducer as a stimulation source. The depth profiling relies on the time delays of the temperature increases at the surface from the different defect depths. To process the time vs. temperature data captured from the camera, polynomial curve fitting was used. A mathematical model has been built to calculated time vs. second derivative of temperature curves for depth measurements. The samples used to calibrate the mathematical model data are carbon fiber composite panels with ply thickness variance and inserts with known depths.
Zhao, Selina X.; Han, Xiaoyan; Favro, Lawrence D.; Newaz, Golam; Thomas, Robert L.
Imaging of SiC in metal matrix composites
TEM has advantages over XRD in determining lattice periodicity. This paper reports an attempt in matching a simulation to an experimental image of SiC in an Al-8.5wt%Fe-1.3 wt%V-1.7 wt%Si composite containing 15 wt% SiC particulates, processed by powder metallurgy. The hexagonal allotrope has predominantly the 6H polytype structure; 1/3 of the 15R polytype is also observed. This SiC structure represents the 87R polytype. 6 refs, 2 figs.
Radmilovic, V. [Belgrade Univ. (Yugoslavia). Dept. of Physical Metallurgy; O`Keefe, M.A.; Thomas, G. [Lawrence Berkeley Lab., CA (United States)
Tensor Processing for Texture and Colour Segmentation
\\u000a In this paper, we propose an original approach for texture and colour segmentation based on the tensor processing of the nonlinear\\u000a structure tensor. While the tensor structure is a well established tool for image segmentation, its advantages were only partly\\u000a used because of the vector processing of that information. In this work, we use more appropriate definitions of tensor distance
Rodrigo De Luis Garc�a; Rachid Deriche; Mika�l Rousson; Carlos Alberola-l�pez
Taylor impact tests on PBX composites: imaging and analysis
NASA Astrophysics Data System (ADS)
A series of Taylor impact tests were performed on three plastic bonded explosive (PBX) formulations: PBX 9501, PBXN-9 and HPP (propellant). The first two formulations are HMX-based, and all three have been characterized quasi-statically in tension and compression. The Taylor impact tests use a 500 psi gas gun to launch PBX projectiles (approximately 30 grams, 16 mm diameter, 76 mm long), velocities as high as 215 m/s, at a steel anvil. Tests were performed remotely and no sign of ignition/reaction have been observed to date. Highspeed imaging was used to capture the impact of the specimen onto anvil surface. Side-view contour images have been analyzed using dynamic stress equations from the literature, and additionally, front-view images have been used to estimate a tensile strain failure criterion for initial specimen fracture. Post-test sieve analysis of specimen debris correlates fragmentation with projectile velocity, and these data show interesting differences between composites. Along with other quasi-static and dynamic measurements, Taylor impact images and fragmentation data provide a useful metric for the calibration or evaluation of intermediate-rate model predictions of PBX constituitive response and failure/fragmentation. Intermediate-rate tests involving other impact configurations are being considered.
Graff Thompson, Daria; DeLuca, Racci; Archuleta, Jose; Brown, Geoff W.; Koby, Joseph
Colour misbinding during motion rivalry
When two dissimilar colours are displayed to the two eyes at overlapping retinal locations, binocular rivalry typically results: a fluctuating struggle for perceptual dominance of each eye's stimulus. We found instead that isoluminant counter-rotating patterns consisting of coloured and achromatic portions can promote an illusory colour �misbinding�, where the colours from both eyes were perceived within a single rotating pattern. The achromatic portion of one rotating pattern thus appeared to take on the colour of the other, oppositely rotating pattern. The results suggest that the neural mechanisms of colour binding can operate even while representations of the same patterns' motions are undergoing rivalry, and support the idea that rivalry can occur in isolation within the motion system.
Maloney, Ryan T.; Lam, Sarah K.; Clifford, Colin W. G.
Content-based image retrieval systems typically query image databases based on some colour and textural features. Optimal robust features should be geometrically and illumination invariant. Although image retrieval has been an active research area for many years this dicult problem is still far from being solved. Simpler methods based only on colour features achieve illumination invariance by normalising colour bands or using a colour ratio histogram. However colour based methods rarely perform suciently in natural visual scenes because they cannot detect similar objects in dierent
location, illumination or backgrounds. Textures are important clues to specify objects present in a visual scene. Unfortunately the appearance of natural rough textures is highly illumination dependent. As a consequence most recent rough texture based classification or segmentation methods require multiple training images captured under a full variety of possible illumination conditions for each class. Such learning is obviously clumsy
Pavel Vacha; Michal Haindl
Damage Assessment of Composite Structures Using Digital Image Correlation
NASA Astrophysics Data System (ADS)
The steady increase of Carbon-Fiber Reinforced Polymer (CFRP) Structures in modern aircraft will reach a new dimension with the entry into service of the Boeing 787 and Airbus 350. Replacement of damaged parts will not be a preferable solution due to the high level of integration and the large size of the components involved. Consequently the need to develop repair techniques and processes for composite components is readily apparent. Bonded patch repair technologies provide an alternative to mechanically fastened repairs with significantly higher performance, especially for relatively thin skins. Carefully designed adhesively bonded patches can lead to cost effective and highly efficient repairs in comparison with conventional riveted patch repairs that cut fibers and introduce highly strained regions. In this work, the assessment of the damage process taking place in notched (open-hole) specimens under uniaxial tensile loading was studied. Two-dimensional (2D) and three-dimensional (3D) Digital Image Correlation (DIC) techniques were employed to obtain full-field surface strain measurements in carbon-fiber/epoxy T700/M21 composite plates with different stacking sequences in the presence of an open circular hole. Penetrant enhanced X-ray radiographs were taken to identify damage location and extent after loading around the hole. DIC strain fields were compared to finite element predictions. In addition, DIC techniques were used to characterise damage and performance of adhesively bonded patch repairs in composite panels under tensile loading. This part of work relates to strength/stiffness restoration of damaged composite aircraft that becomes more important as composites are used more extensively in the construction of modern jet airliners. The behaviour of bonded patches under loading was monitored using DIC full-field strain measurements. Location and extent of damage identified by X-ray radiography correlates well with DIC strain results giving confidence to the technique for structural health monitoring of bonded patches.
Caminero, M. A.; Lopez-Pedrosa, M.; Pinna, C.; Soutis, C.
Three cortical stages of colour processing in the human brain.
We used the technique of functional magnetic resonance imaging to chart the colour pathways in the human brain beyond V4. We asked subjects to view objects that were dressed in natural and unnatural colours as well as their achromatic counterparts and compared the activity produced in the brain by each condition. The results showed that both naturally and unnaturally coloured objects activate a pathway extending from V1 to V4, though not overlapping totally the activity produced by viewing abstract coloured Mondrian scenes. Normally coloured objects activated, in addition, more anterior parts of the fusiform gyrus, the hippocampus and the ventrolateral frontal cortex. Abnormally coloured objects, by contrast, activated the dorsolateral frontal cortex. A study of the cortical covariation produced by these activations revealed that activity in large parts of the occipital lobe covaried with each. These results, considered against the background of previous physiological and clinical studies, allow us to discern three broad cortical stages of colour processing in the human brain. The first is based on V1 and possibly V2 and is concerned mainly with registering the presence and intensity of different wavelengths, and with wavelength differencing. The second stage is based on V4 and is concerned with automatic colour constancy operations, without regard to memory, judgement and learning. The third stage, based on the inferior temporal and frontal cortex, is more concerned with object colours. The results we report, as well as the schema that we suggest, also allow us to reconcile the computational theory of Land, implemented without regard to cognitive factors such as memory and learning, and the cognitive systems of Helmholtz and Hering, which view such factors as critical in the determination of colours. PMID:9762956
Zeki, S; Marini, L
Content-Based Image Retrieval Using a Composite Color-Shape Approach.
ERIC Educational Resources Information Center
Proposes a composite feature measure which combines the shape and color features of an image based on a clustering technique. A similarity measure computes the degree of match between a given pair of images; this technique can be used for content-based image retrieval of images using shape and/or color. Tests the technique on two image databases;�
Mehtre, Babu M.; Kankanhalli, Mohan S.; Lee, Wing Foon
Colorimetric characterisation of flatbed scanners for rock/sediment imaging
NASA Astrophysics Data System (ADS)
Colour is a physical property of rocks and sediments that has the potential to provide key insights into composition, and by extension the physical and chemical processes governing deposition. The rapid, non-destructive measurement of colour using spectrophotometers is an increasingly popular way of generating long datasets (i.e. >1000 data points) suitable for high-resolution palaeoclimate analysis. Digital image analysis of core photographs is another commonly applied method of extracting colour information, but the application of flatbed scanners for direct rock and sediment colour measurement has not received widespread attention. Here, a simple calibration methodology is presented that demonstrates how scanners can be colorimetrically characterised. The technique offers a quantitative approach to colour analysis that is superior to the subjective comparison of rocks/sediments to Munsell colour charts. Moreover, the accuracy of the method makes rock and sediment scanning a viable alternative to colour analysis using spectrophotometers. The technique is applied to Late Pleistocene sediment samples from the Canterbury Basin, New Zealand (IODP 317, Site U1352B) to emphasise the utility and precision of the method and the tight relationship between sediment colour and composition.
Kemp, David B.
Field-aligned 777.4-nm composite airglow images of equatorial plasma depletions
We present a powerful tool to analyze two-dimensional field-aligned images of equatorial plasma depletions taken from mid-latitudes. By shifting each individual image by the sum of the longitudinal offsets obtained by performing a cross-correlation between successive images, a single composite image can be formed for the entire night. It is shown that these field-aligned composite images give information on the
J. J. Makela; M. C. Kelley
Hyperspectral imaging of structure and composition in atomically thin heterostructures.
Precise vertical stacking and lateral stitching of two-dimensional (2D) materials, such as graphene and hexagonal boron nitride (h-BN), can be used to create ultrathin heterostructures with complex functionalities, but this diversity of behaviors also makes these new materials difficult to characterize. We report a DUV-vis-NIR hyperspectral microscope that provides imaging and spectroscopy at energies of up to 6.2 eV, allowing comprehensive, all-optical mapping of chemical composition in graphene/h-BN lateral heterojunctions and interlayer rotations in twisted bilayer graphene (tBLG). With the addition of transmission electron microscopy, we obtain quantitative structure-property relationships, confirming the formation of interfaces in graphene/h-BN lateral heterojunctions that are abrupt on a micrometer scale, and a one-to-one relationship between twist angle and interlayer optical resonances in tBLG. Furthermore, we perform similar hyperspectral imaging of samples that are supported on a nontransparent silicon/SiO2 substrate, enabling facile fabrication of atomically thin heterostructure devices with known composition and structure. PMID:23841492
Havener, Robin W; Kim, Cheol-Joo; Brown, Lola; Kevek, Joshua W; Sleppy, Joel D; McEuen, Paul L; Park, Jiwoong
NASA Astrophysics Data System (ADS)
We present a survey of results from various research groups under the unifying viewpoint of transformational physics, which has been recently introduced for the design of metamaterials in optics and acoustics. We illustrate the versatility of underlying geometric transforms in order to bridge wave phenomena (the different 'colours' of waves) ranging from transverse electric waves, to linear surface water waves at an air-fluid interface, to pressure waves in fluids and out-of-plane shear waves in elastic media: these waves are all governed by a second order scalar partial differential equation (PDE) invariant under geometric transform. Moreover, flexural waves propagating in thin plates represent a very peculiar situation whereby the displacement field satisfies a fourth order scalar PDE which also retains its form under geometric transform (unlike for the Navier equation in elastodynamics). Control of flexural wave trajectories is illustrated with a multilayered cloak and a carpet. Interestingly, the colours of waves can be revealed through an analysis of the band spectra of invisibility cloaks. In the context of acoustics, this suggests one can hear the shape of a drum. Alternative avenues towards cloaking based upon anomalous resonances of a negatively refracting coating (which can be seen as the result of folding the space back onto itself), and even plasmonic shells reducing the scattering cross-section of nano-objects are also addressed.
Guenneau, S�bastien; McPhedran, Ross C.; Enoch, Stefan; Movchan, Alexander B.; Farhat, Mohamed; Nicorovici, Nicolae-Alexandru P.
Exploring consumers' product-specific colour meanings
Purpose � The impact of colour is acknowledged, yet empirical studies on colours with marketing implications are rare. The paper seeks to advance our understanding of the role of package colours in consumers' product experiences by studying the relationship between colour meanings and product. It also aims at offering insights into the meanings associated with colours in a product context.
Hannele Kauppinen-R�is�nen; Harri T. Luomala
Image and Signal Processing Algorithms for Thz Imaging of Composite Materials
NASA Astrophysics Data System (ADS)
Terahertz time domain pulsed NDT inspection of composite materials creates opportunity to achieve signals allowing to identify various defects types very precisely. In this paper algorithms for signal processing of THz B- and C-scans will be presented. Enhanced THz images enable better defects reconstruction and classification results. Proposed algorithms were verified using signals achieved for various types of defects. For this reason a catalogue of possible defects is under preparation.
Lopato, P.; Chady, T.; Goracy, K.
Algorithms for Moderate Resolution Imaging Spectroradiometer cloud-free image compositing
NASA Astrophysics Data System (ADS)
The presence of clouds is the biggest obstacle in the investigation of land cover, and many techniques have been developed to detect clouds. However, few indicators have been proposed for the detection of cloud-free conditions. To address this, we propose two indicators for use in compositing 8-day cloud-free images: the B ratio is the ratio of the band 1 reflectance to the band 7 reflectance of Terra surface reflectance images (MOD09GA), and saturation refers to the color saturation of these images. Here, we describe the principles underlying these two indicators and analyze their characteristics for vegetation, water, urban, and nonvegetation pixels under cloud-free, cloud shadow, and cloudy conditions using MOD09GA from October 16 to 23, 2007, in North China (sample A) and using data published by the U.S. Geological Survey (USGS). We found that the B ratio and saturation are suitable for extracting cloud-free pixels over land and water, respectively; therefore, we combined these two indicators to develop a single-unified model. In particular, our results demonstrate that the pixels exhibiting the lowest B ratios should be adopted as cloud-free pixels over land when the value of B for land surfaces is between 0 and 1, and the surface reflectance of Moderate Resolution Imaging Spectroradiometer band 1 is less than 0.3. Otherwise, the pixels exhibiting the greatest saturation values should be adopted. We used our model to composite cloud-free images for two additional regions in China: the Tarim basin (sample B) from October 2 to 9, 2012, and the coastal areas of southeastern China (sample C) from April 15 to 23, 2013. We compared the cloud-free images of these regions with the 8-day surface reflectance product (MOD09A1) with respect to clouds, cloud shadow, and cirrus clouds, and we found that our proposed cloud-free image compositing approach can accurately eliminate both clouds and cirrus clouds. Specifically, the percentage of residual cloud pixels in sample C was found to be less than that in MOD09A1. Moreover, in the cloud-free images obtained using our newly developed method, cloud-free pixels are typically associated with greater sensor zenith angles and smaller scatter angles than those in MOD09A1. However, our method retains some limitations. In particular, 9.68, 33.22, and 33.00% of cloud-shadow pixels remain in the cloud-free images for samples A, B, and C, respectively.
Xiang, Hai-bing; Liu, Jin-song; Cao, Chun-xiang; Xu, Min
Complementary Colours for a Physicist
ERIC Educational Resources Information Center
This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing�
Babic, Vitomir; Cepic, Mojca
Factorial Analysis of Colour Vision
HOUSTOUN1 has pointed out that a three-colour theory, such as that of Young and Helmholtz, inevitably leads to mathematical contradictions. It is well known in addition that a theory in which there are only three primary sensitivities, such as red, green and blue, becomes unsatisfactory when the many different forms of defective colour vision are studied in detail. Pi�ron2 has
R. W. Pickford
CIE Colorimetry and Colour Displays
CIE colorimetry was standardised 65 years ago to describe colorimetric properties of signal lights. The first real application of CIE colorimetry occurred, however, in the textile and coating industries to describe colour matches between sample and reference. Thus also the experiments conducted to achieve a uniform colour scale diagram were performed by using material samples usually illuminated by a daylight
J Schanda
Chemical composition, vitamin E content, lipid oxidation, colour and cooking losses in meat from Tudanca bulls finished on semi-extensive or intensive systems and slaughtered at 12 or 14 months.
The effects of production system (SE: pasture based vs. IN: concentrate based) and slaughter age (12 vs. 14 months) on chemical composition, vitamin E and myoglobin contents, lipid oxidation at 0, 3 and 6 days of display, colour and cooking losses at 2 and 7 days postmortem from thirty-three Tudanca calves were studied. SE animals showed lower IMF and greater vitamin E contents (1.2 vs. 2.9% and 4.1 vs. 1.8 ?g/g, respectively). Thiobarbituric acid reactive substances (TBARS) increased (p ? 0.001) with display time and was greater in the IN system. After 6 days display, IN animals presented twofold TBARS values (1.4 vs. 0.8 mg malonaldehyde/kg meat). At 7 days postmortem, SE groups presented greater (p ? 0.05) L* and lower (p ? 0.05) b* and H� than IN groups. Myoglobin increased with age (3.4 to 3.9 mg/g meat), but differences (p ? 0.05) on a* and C* values were observed only between 12 and 14 months at 2 days postmortem. PMID:24211548
Humada, M J; Sa�udo, C; Serrano, E
Compositional maps of Saturn's moon Phoebe from imaging spectroscopy
The origin of Phoebe, which is the outermost large satellite of Saturn, is of particular interest because its inclined, retrograde orbit suggests that it was gravitationally captured by Saturn, having accreted outside the region of the solar nebula in which Saturn formed. By contrast, Saturn's regular satellites (with prograde, low-inclination, circular orbits) probably accreted within the sub-nebula in which Saturn itself formed. Here we report imaging spectroscopy of Phoebe resulting from the Cassini-Huygens spacecraft encounter on 11 June 2004. We mapped ferrous-iron-bearing minerals, bound water, trapped CO2, probable phyllosilicates, organics, nitriles and cyanide compounds. Detection of these compounds on Phoebe makes it one of the most compositionally diverse objects yet observed in our Solar System. It is likely that Phoebe's surface contains primitive materials from the outer Solar System, indicating a surface of cometary origin.
Clark, R. N.; Brown, R. H.; Jaumann, R.; Cruikshank, D. P.; Nelson, R. M.; Buratti, B. J.; McCord, T. B.; Lunine, J.; Baines, K. H.; Bellucci, G.; Bibring, J. -P.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Formisano, V.; Langevin, Y.; Matson, D. L.; Mennella, V.; Nicholson, P. D.; Sicardy, B.; Sotin, C.; Hoefen, T. M.; Curchin, J. M.; Hansen, G.; Hibbits, K.; Matz, K. -D.
User preferences in colour enhancement for unsupervised printing methods
NASA Astrophysics Data System (ADS)
In order to obtain a good quality image in preparation for inkjet printing, the process of adjusting images can be a time consuming and a costly procedure. In this paper, we consider the use of an unsupervised colour enhancement method as part of the automatic pre-processors for printing. Other unsupervised colour enhancement methods are utilised and compared: Retinex, RSR, ACE, Histogram Equalisation, Auto Levels. Test images are subjected to all of the enhancement methods, which are then printed. Users are asked compare each of the sampled images. In all cases, the results are dependent on the image. Thus, we have selected a range of test images: photographs of scenes, reproduction of prints, paintings and drawings. Some of the tested methods are parameter dependent. We do not intend to consider fine tuning for each of the techniques, rather to consider an average parameter set for each one and then test if this approach can aid the decision process of fine tuning. Three user groups are employed: the general user, commercial photographer expert and fine artist. Groups are asked to make a blind evaluation of a range of images (the original and the colour enhanced by the different methods); these are randomly placed. All images are printed on the same printer using the same settings. Users are asked to identify their preferred print in relation to lightness, tonal range, colour range, quality of detail and overall subjective preference.
Parraman, Carinna; Rizzi, Alessandro
This paper discusses a technique to convert 2 dimensional images into music by associating hue values with timbres. The colour information in 2D still images was used to drive an 8 channel timbral audio mixer. 8 musical timbres were recorded to represent 8 hue values and these timbres were changed in amplitude dependent on the quantity of each hue in
Dave Payling; Stella Mills
Prediction of compositional and sensory characteristics using RGB digital images and multivariate calibration techniques.
In the present paper, the possibility to use the information contained in RGB digital images to gain a fast and inexpensive quantification of colour-related properties of food is explored. To this aim, we present an approach which consists, as first step, in condensing the colour related information contained in RGB digital images of the analysed samples in one-dimensional signals, named colourgrams. These signals are then used as descriptor variables in multivariate calibration models. The feasibility of this approach has been tested using as a benchmark a series of samples of pesto sauce, whose RGB images have been used to predict both visual attributes defined by a panel test and the content of various pigments (chlorophylls a and b, pheophytins a and b, ?-carotene and lutein). The possibility to predict correctly the values of some of the studied parameters suggests the feasibility of this approach for fast monitoring of the main aspect-related properties of a food matrix. The values of the squared correlation coefficient computed in prediction on a test set (R(Pred)(2)) for green and yellow hues were greater than 0.75, while R(Pred)(2) values greater than 0.85 were obtained for the prediction of total chlorophylls content and of chlorophylls/pheophytins ratio. The great flexibility of this blind analysis method for the quantitative evaluation of colour related features of matrices with an inhomogeneous aspect suggests that it is possible to implement automated, objective, and transferable systems for fast monitoring of raw materials, different stages of the manufacture and end products, not necessarily for the food industry only. PMID:22023857
Foca, Giorgia; Masino, Francesca; Antonelli, Andrea; Ulrici, Alessandro
Nondestructive inspection of tagged composites using real-time magneto-optic imaging
While magneto-optic\\/eddy current imagers (MOIs) are widely used for the nondestructive inspection (NDI) of aging aluminum airframes, they are not currently used to inspect aerospace composites for two reasons. First, most composites are essentially electrical insulators, which makes it difficult for the MOI to induce sufficient eddy currents in these materials for imaging. Second, unlike steel, which can be easily
Gerald L. Fitzpatrick; David K. Thome; Richard L. Skaugset; William C. Shih
Optimal colour quality of LED clusters based on memory colours.
The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant. PMID:21451716
Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter
Meaning-Making with Colour in Multimodal Texts: An 11-Year-Old Student's Purposeful "Doing"
ERIC Educational Resources Information Center
Colour, a visual element of art and design, is a semiotic mode that is used strategically by sign-makers to communicate meaning. Understanding the meaning-making potential of colour can enhance students' understanding, appreciation, interpretation and composition of multimodal texts. This article features a case study of Anya, an 11-year-old�
Pantaleo, Sylvia
Colour Graphics for Hydrocode Simulations.
National Technical Information Service (NTIS)
This report describes the production of colour graphical output for the two dimensional finite difference reactive hydrocodes currently used by Weapons Systems Division. The programs use the NCAR graphics package and show how the careful choice appropriat...
A. Doyle D. A. Jones G. Kemister
Light sources with limited spectral content cannot render colours correctly. Typical spectra of phosphor white and RGB LEDs often result in a low colour rendering index, in spite of a high appreciation of LED lighting in visual experiments. The standard approach to colour rendering evaluation has always been based on a relative assessment: the colour coordinates of a set of
Kevin Smet; W. R. Ryckaert; G. Deconinck; Peter Hanselaer; Gebroeders Desmetstraat
Colour as visual rhetoric in financial reporting
Visual rhetoric within communication seeks to persuade through the use of picturing and encompasses words and colour. Visual rhetoric is present within annual reports. The specific role of colour in financial reporting is a neglected field of enquiry. A survey of 100 Hong Kong annual reports related colour usage to profitability change and found companies used more colour when profitability
John K. Courtis
Sexual colouration and sperm traits in guppies
The relationships among the area, hue, saturation and brightness of orange colouration and sperm traits in the guppy Poecilia reticulata were investigated. Males with greater areas of orange colouration had significantly larger sperm loads, more motile sperm and longer sperm relative to males with relatively little orange colouration. Males with greater areas of orange colouration did not possess more viable
T. E. Pitcher; F. H. Rodd; L. Rowe
Colour preferences of flower-naive honeybees
Flower-naive honeybees Apis mellifera L. flying in an enclosure were tested for their colour preferences. Bees were rewarded once on an achromatic (grey, aluminium or hardboard), or on a chromatic (ultraviolet) disk. Since naive bees never alighted on colour stimuli alone, a scent was given in combination with colour. Their landings on twelve colour stimuli were recorded. Results after one
M. Giurfa; J. N��ez; L. Chittka; R. Menzel
Colour print workflow and methods for multilayering of colour and decorative inks using UV inkjet for fine art printing
NASA Astrophysics Data System (ADS)
In order to increase density of colour and improve ink coverage when printing onto a range of non standard substrates, this paper will present research into multi-layering of colour and the appearance of colour at 'n' levels of ink coverage. Returning to our original investigation of artist's requirements when making inkjet prints, these observations are based on empirical approaches that address the need to present physical data that is more useful and meaningful to the designer. The study has used multi-pass printed colour charts to measure colour and to provide users with an understanding at a soft-preview level to demonstrate the appearance of printed colour on different substrates. Test results relating to the appearance of print on different surfaces, and a series of case studies will be presented using recent research into the capabilities of UV printing technology, which has widened the opportunities for the designer to print onto non-standard materials. It will also present a study into layering of greys and gloss in order to improve the appearance of printed images onto metal.
Parraman, Carinna
In this paper a detection road sign system, based on the analysis of colour images, is presented. This system aims at recovering the images regions that have colours similar to those present in road signs (red, white, black, blue). For each colour and inside adequate colour space, heuristic threshold decision are identified. Dynamic thresholds don't suffer from the illumination change
Colour variability of asteroids in the Sloan Digital Sky Survey Moving Object Catalog
NASA Astrophysics Data System (ADS)
We report a detection of statistically significant colour variations for a sample of 7531 multiply observed asteroids that are listed in the Sloan Digital Sky Survey Moving Object Catalog. Using five-band photometric observations accurate to ~0.02 mag, we detect colour variations in the range 0.06-0.11 mag (rms). These variations appear to be uncorrelated with the physical characteristics of the asteroids, such as diameter (in the probed 1-10 km range), taxonomic class and family membership. Despite this lack of correlation, which implies a random nature for the cause of colour variability, a suite of tests suggest that the detected variations are not instrumental effects. In particular, the observed colour variations are incompatible with photometric errors, and, for objects observed at least four times, the colour change in the first pair of observations is correlated with the colour change in the second pair. These facts strongly suggest that the observed effect is real, and also indicate that colour variations are larger for some asteroids than for others. The detected colour variations can be explained as being due to inhomogeneous albedo distribution over an asteroid's surface. Although relatively small, these variations suggest that fairly large patches with different colour than their surroundings exist on a significant fraction of asteroids. This conclusion is in agreement with spatially resolved colour images of several large asteroids obtained by the Near Earth Asteroid Rendezvous (NEAR) spacecraft and the Hubble Space Telescope (HST).
Szab�, Gy. M.; Ivezi?, �.; Juri?, M.; Lupton, R.; Kiss, L. L.
Methods and Compositions to Reduce Scattering of Light During Therapeutic and Diagnostic Imaging Procedures.
National Technical Information Service (NTIS)
Disclosed are improved methods and compositions for use in light-based in vivo imaging and treatment. The techniques described involve the use of low-scattering, oxygen-carrying blood substitutes in imaging and treatment methods, including OCT imaging. Th...
J. W. Villard M. D. Feldman T. E. Milner
Class Separation Improvements in Pixel Classification Using Colour Injection
This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required.
Blanco, Edward; Mazo, Manuel; Bergasa, Luis; Palazuelos, Sira; Rodriguez, Jose; Losada, Cristina; Martin, Jose
Increasing land-use intensity decreases floral colour diversity of plant communities in temperate grasslands.
To preserve biodiversity and ecosystem functions in a globally changing world it is crucial to understand the effect of land use on ecosystem processes such as pollination. Floral colouration is known to be central in plant-pollinator interactions. To date, it is still unknown whether land use affects the colouration of flowering plant communities. To assess the effect of land use on the diversity and composition of flower colours in temperate grasslands, we collected data on the number of flowering plant species, blossom cover and flower reflectance spectra from 69 plant communities in two German regions, Schw�bische Alb (SA) and Hainich-D�n (HD). We analysed reflectance data of flower colours as they are perceived by honeybees and studied floral colour diversity based upon spectral loci of each flowering plant species in the Maxwell triangle. Before the first mowing, flower colour diversity decreased with increasing land-use intensity in SA, accompanied by a shift of mean flower colours of communities towards an increasing proportion of white blossom cover in both regions. By changing colour characteristics of grasslands, we suggest that increasing land-use intensity can affect the flower visitor fauna in terms of visitor behaviour and diversity. These changes may in turn influence plant reproduction in grassland plant communities. Our results indicate that land use is likely to affect communication processes between plants and flower visitors by altering flower colour traits. PMID:23568710
Binkenstein, Julia; Renoult, Julien P; Schaefer, H Martin
Carotenoid-Based Colours Reflect the Stress Response in the Common Lizard
Under chronic stress, carotenoid-based colouration has often been shown to fade. However, the ecological and physiological mechanisms that govern colouration still remain largely unknown. Colour changes may be directly induced by the stressor (for example through reduced carotenoid intake) or due to the activation of the physiological stress response (PSR, e.g. due to increased blood corticosterone concentrations). Here, we tested whether blood corticosterone concentration affected carotenoid-based colouration, and whether a trade-off between colouration and PSR existed. Using the common lizard (Lacerta vivipara), we correlatively and experimentally showed that elevated blood corticosterone levels are associated with increased redness of the lizard's belly. In this study, the effects of corticosterone did not depend on carotenoid ingestion, indicating the absence of a trade-off between colouration and PSR for carotenoids. While carotenoid ingestion increased blood carotenoid concentration, colouration was not modified. This suggests that carotenoid-based colouration of common lizards is not severely limited by dietary carotenoid intake. Together with earlier studies, these findings suggest that the common lizard's carotenoid-based colouration may be a composite trait, consisting of fixed (e.g. genetic) and environmentally elements, the latter reflecting the lizard's PSR.
Fitze, Patrick S.; Cote, Julien; San-Jose, Luis Martin; Meylan, Sandrine; Isaksson, Caroline; Andersson, Staffan; Rossi, Jean-Marc; Clobert, Jean
Estimation of sheep and pig body composition by x-ray CT, MRI, and ultrasound imaging
NASA Astrophysics Data System (ADS)
Non-invasive imaging techniques have revolutionized diagnostic medicine, and promise to do likewise in animal experimentation and breeding. In this paper, three applications are described in which the objective is to predict body composition.
Glasbey, Chris A.
Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads:
NASA Technical Reports Server (NTRS)
Artist: Ken Hodges Composite image explaining Objective and Motivation for Galileo Probe Heat Loads: Galileo Probe descending into Jupiters Atmosphere shows heat shield separation with parachute deployed. (Ref. JPL P-19180)
Assessing the Applicability of Digital Image Correlation (DIC) Technique in Tensile Testing of Fabric Composites.
National Technical Information Service (NTIS)
Performing mechanical characterization of novel structural materials and accounting for the types of failures observed and the heterogeneous nature of fiber-reinforced composites (FRCs) require non-contact strain measurements such as Digital Image Correla...
B. P. Justusson D. M. Spagnuolo J. H. Yu
Non-contact imaging of carbon composite structures using electric potential (displacement current) sensors
NASA Astrophysics Data System (ADS)
In this paper we describe an experimental technique for imaging defects in carbon composite structures non-invasively using ultra-high input impedance electric potential (displacement current) sensors. We suggest that with suitable two-dimensional arrays of these sensors it should prove practicable to image in real time, and in situ, large scale carbon composite structures such as aircraft wing and tail surfaces.
Gebrial, W.; Prance, R. J.; Harland, C. J.; Stiffell, P. B.; Prance, H.; Clark, T. D.
Progress on Developing Sonic Infrared Imaging for Defect Detection in Composite Structures
At last year's QNDE conference, we presented our development of Sonic IR imaging technology in metal structures, with results from both experimental studies and theoretical computing. In the latest aircraft designs, such as the B787 from Boeing, composites have become the major materials in structures such as the fuselage and wings. This is in contrast to composites' use only in
Xiaoyan Han; Qi He; Wei Li; Golam Newaz; Lawrence D. Favro; Robert L. Thomas
Colour Glass Condensate: An Introduction.
National Technical Information Service (NTIS)
In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures a...
E. Iancu A. Leonidov L. McLerran
Colour of Red Blood Corpuscles
IN a recent communication1, Dr. J. R. Baker has asked why a single red blood corpuscle looks yellow instead of pink. Whether a thinned-out red colour is pink or yellow depends on the extent of its absorption in the blue end of the spectrum. Let us for simplicity regard white light as composed of equal parts of red, green and
E. J. Bowen
Interference colours of soap bubbles
In this article, we present a new versatile method for calculating the interference colour of any configuration of thin, optically isotropic, dielectric films. This method is free from common weakness of previous methods, namely the poor accuracy for large angles of incidence of light. This method gives full control over the accuracy and speed of computations, and allows for adjustments
Dariusz Jaszkowski; Janusz Rzeszut
Nondestructive inspection of tagged composites using real-time magneto-optic imaging
NASA Astrophysics Data System (ADS)
While magneto-optic/eddy current imagers (MOIs) are widely used for the nondestructive inspection (NDI) of aging aluminum airframes, they are not currently used to inspect aerospace composites for two reasons. First, most composites are essentially electrical insulators, which makes it difficult for the MOI to induce sufficient eddy currents in these materials for imaging. Second, unlike steel, which can be easily magnetized and inspected using the MOI, most composites are not appreciably magnetic. Exceptions to these two stated limitations are composites containing electrically conducting 'screens' of aluminum or copper for lighting-protection, 'stealthy' military composites containing iron particles for radar absorption, and some commercial composites containing nickel-coated carbon fibers for lighting protection and/or electromagnetic shielding. These existing composites can be inspected, to one degree or another,with the MOI. Moreover, by 'tagging' the matrix component of newly-manufactured composites with magnetic oxides, excellent MOI images of cracks, voids, potential disbonds and defects in fiber-weave are possible. Experimental results presented here demonstrate these facts. It is anticipated that when this new technology is perfected, and when magnetic 'tagging' at the time of manufacture becomes an accepted practice, the MOI will be widely used for the NDI of composites during their manufacture, in-service inspection or repair.
Fitzpatrick, Gerald L.; Thome, David K.; Skaugset, Richard L.; Shih, William C.
The colour of the dark side of the Moon
NASA Astrophysics Data System (ADS)
Aims: "Earthshine" is the dim light seen on the otherwise dark side of the Moon, particularly when it is close to new. "Earthlight", or reflected sunlight from the Earth, is the source of Earthshine. Using B and V band CCD images of both the dark and bright sides of the Moon, we aim to estimate the Johnson photometry B - V colour of the Earthshine for the first time since the late 1960s. From these measurements we are also able to quantify the colour of Earthlight. Methods: We present images of the Moon taken with a small refractor in Hawaii, in B and V bands and taken under favourable conditions so that scattered light in both bands almost completely cancels, yielding a map of the surface in B - V colour. Co-addition of 100 such images taken in rapid succession substantially improves the signal-to- noise ratio, and several sources of photometric bias are eliminated by use of relative methods. Results: The earthlit dark side of the Moon is observed to be 0.150 � 0.005 mag bluer in B - V than the sunlit bright side, in good agreement with the only known previous measurement of this quantity from 1967. Arguing on the basis of the change in B - V for sunlight reflected once off the Moon, we derive a colour for earthlight of B - V = 0.44 � 0.02 mag (without applying a small, uncertain, phase-dependent reddening correction). The absence of a colour-gradient in the B - V image implies that the scattering properties of the atmosphere+optical system are almost exactly matched in the two wavelength bands, the consequences of which are discussed.
Thejll, P.; Flynn, C.; Gleisner, H.; Andersen, T.; Ulla, A.; O-Petersen, M.; Darudi, A.; Schwarz, H.
Nondestructive Evaluation of Aircraft Composites Using Dielectric Properties and Imaging in the Terahertz Spectrum
Terahertz imaging and dielectric property measurements were assessed as nondestructive evaluation techniques for damage to aircraft glass fiber composites. Samples with localized heat damage showed a minimal change in refractive index or absorption coefficient; however, material blistering was detected. Voids were located by terahertz imaging using amplitude and phase techniques. Delamination depths were approximated by measuring the timing of Fabry-Perot
C. D. Stoik; M. J. Bohn; J. L. Blackshire
Terahertz imaging and dielectric property measurements were assessed as nondestructive evaluation techniques for damage to aircraft glass fiber composites. Samples with localized heat damage showed a minimal change in refractive index or absorption coefficient; however, material blistering was detected. Voids were located by terahertz imaging using amplitude and phase techniques. Delamination depths were approximated by measuring the timing of Fabry-Perot
C. D. Stoik; M. J. Bohn; J. L. Blackshire
Shrinkage vector determination of dental composite by ?CT images
Hypotheses about contraction patterns of light-curing dental composites are controversial. The purpose of this study was to develop a method to determine the direction and extent of polymerization shrinkage. Cavities were restored with a modified composite that contained traceable particles, and digitized before and after light-curing with micro-computed tomography (?CT). The resulting displacement vector fields based on the elastic registration
Yu-Chih Chiang; Reinhard Hickel; Chun-Pin Lin; Karl-Heinz Kunzelmann
Distortion-free single point imaging of multi-layered composite sandwich panel structures.
The results of a magnetic resonance imaging (MRI) investigation concerning the effects of an aluminum honeycomb sandwich panel on the B1 and B0 fields and on subsequent image quality are presented. Although the sandwich panel structure, representative of an aircraft composite material, distorts B0 and attenuates B1, distortion-free imaging is possible using single point (constant time) imaging techniques. A new expression is derived for the error caused by gradient field distortion due to the heterogeneous magnetic susceptibility within a sample and this error is shown not to cause geometric distortion in the image. The origin of the B0 distortion in the sample under investigation was also examined. The graphite-epoxy 'skin' of the panel is the principal source of the B0 distortion. Successful imaging of these structures sets the stage for the development of methods for detecting moisture ingress and degradation within composite sandwich structures. PMID:15082262
Marble, Andrew E; Mastikhin, Igor V; MacGregor, Rod P; Akl, Mohamad; LaPlante, Gabriel; Colpitts, Bruce G; Lee-Sullivan, Pearl; Balcom, Bruce J
This paper is designed to provide a knowledge of the elements of colour theory and an up-to-date survey of methods of specifying colour tolerances. It is intended to fill the gap between textbooks on colour and publications that deal mainly with applications of colour theory to specific problems.
D. Leverington
The connotations of English colour terms: Colour-based X-phemisms
This paper investigates the connotations of English colour terms with particular attention to figurative uses of black, white, grey, brown, yellow, red, green, blue and a few miscellaneous colours. The connotations are judged on the basis of whether the phrases in which the colour terms occur are typically orthophemistic, euphemistic, or dysphemistic. All the colours surveyed have some, often many,
Keith Allan
Trichromacy, Opponent Colours Coding and Optimum Colour Information Transmission in the Retina
This paper presents a systematic analysis of the role of opponent type processing in colour vision and the relation between opponent type colour transformations and the initial three colour mechanisms. It is shown that efficient information transmission is achieved by a transformation of the initial three colour mechanisms into an achromatic and two opponent chromatic channels. The derivation of the
G. Buchsbaum; A. Gottschalk
Kinetic Model for Colour Changes in Bananas During the Appearance of Chilling Injury Symptoms
The impact of chilling injury (CI) on the colour of bananas at different ripening stages was investigated. Bananas were stored\\u000a at 6 and 13��C for 2�days to induce CI symptoms. Images of the bananas were acquired in 1-h time intervals during the subsequent\\u000a appearance of CI at room temperature using RGB imaging system to monitor the colour changes. The raw
Norhashila Hashim; Rimfiel Bin Janius; Laszlo Baranyai; Russly Abdul Rahman; Azizah Osman; Manuela Zude
Hand gesture recognition using multi-scale colour features, hierarchical models and particle filtering
This paper presents algorithms and a prototype system for hand tracking and hand posture recognition. Hand postures are represented in terms of hierarchies of multi-scale colour image features at different scales, with qualitative inter-relations in terms of scale, position and orientation. In each image, detection of multi-scale colour features is performed. Hand states are then simultaneously detected and tracked using
Lars Bretzner; Ivan Laptev; Tony Lindeberg
Hand-gesture recognition using multi-scale colour features, hierarchical features and particle filtering
This paper presents algorithms and a prototype system for hand tracking and hand posture recognition. Hand pos- tures are represented in terms of hierarchies of multi-scale colour image features at different scales, with qualitative inter-relations in terms of scale, position and orientation. In each image, detection of multi-scale colour features is per- formed. Hand states are then simultaneously detected and
Lars Bretzner; Ivan Laptev; Tony Lindeberg
Biological Components of Colour Preference in Infancy
ERIC Educational Resources Information Center
Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in�
Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya
How feather colour reflects its melanin content
Summary 1. Melanin coloration is the most common type of colour in animals. Many species use melanin-based black, brown, grey or earth-toned colours as intraspecific signals of quality. 2. Melanin comes in two main forms in vertebrates - eumelanin and phaeomelanin - and these are said to create different colours, with eumelanin giving a darker black, brown or grey appearance
K. J. McGRAW; R. J. SAFRAN; K. WAKAMATSU
Innate colour preferences of flower visitors
Freshly emerged flower visitors exhibit colour preferences prior to individual experience with flowers. The understanding of innate colour preferences in flower visitors requires a detailed analysis, as, on the one hand, colour is a multiple-signal stimulus, and, on the other hand, flower visits include a sequence of behavioural reactions each of which can be driven by a preferential behaviour. Behavioural
K. Lunau; E. J. Maier
Nine Tools for Generating Harmonious Colour Schemes
We survey a number of tools that have been developed for generating sets of colours according to commonly accepted rules for colour harmony. Informal manual techniques for generating harmonious sets of colo urs have been known and used for at least a century. Although superficially simple, they have not been precise techniques, as pigment-based and dye-based colouring techniques are not
Paul Lyons; Giovanni Moretti
Memory for colours: a reaction time experiment
We used simultaneous and delayed match to sample tasks to investigate memory for 5 colour tests (green, yellow, purple, pink and orange) in men and women. Stimuli were emulated Munsell colour samples displayed on a CRT monitor. Colour tests were presented with distracters that could vary either in hue or in saturation. Our results indicate that: 1) over the five
V. Bonnardel; J. Herrero
Colour space models for soil science
Soil colour is an important soil property. It is frequently used by soil scientists for the identification and classification of soil. It is also used as an indicator of field soil physical, chemical and biological properties as well as of the occurrence of soil processes. Measurements of soil colour are commonly made using the Munsell soil colour charts. A number
R. A. Viscarra Rossel; B. Minasny; P. Roudier; A. B. McBratney
Thermal imaging of graphite/epoxy composite samples with fabricated defects
NASA Technical Reports Server (NTRS)
Consideration is given to a thermal inspection system for quickly inspecting large area composites for increased reliability and maintainability of helicopters resulting from improved quality assurance manufacturing. The infrared camera/image processor-based inspection system was used to image defects in composites. Noncontacting and single-sided measurements were performed on graphite/epoxy samples with fiber volume fraction variations, fabricated porosity, impact damage, and inclusions in incurred lay ups. These defects were imaged by determining the variations in the cooling rates caused by differences in through ply thermal diffusivity. Attention is also given to the system's sensitivity to measuring the defects due to sample thickness.
Zalameda, Joseph N.; Winfree, William P.
Thermographic imaging for high-temperature composite materials: A defect detection study
NASA Technical Reports Server (NTRS)
The ability of a thermographic imaging technique for detecting flat-bottom hole defects of various diameters and depths was evaluated in four composite systems (two types of ceramic matrix composites, one metal matrix composite, and one polymer matrix composite) of interest as high-temperature structural materials. The holes ranged from 1 to 13 mm in diameter and 0.1 to 2.5 mm in depth in samples approximately 2-3 mm thick. The thermographic imaging system utilized a scanning mirror optical system and infrared (IR) focusing lens in conjunction with a mercury cadmium telluride infrared detector element to obtain high resolution infrared images. High intensity flash lamps located on the same side as the infrared camera were used to heat the samples. After heating, up to 30 images were sequentially acquired at 70-150 msec intervals. Limits of detectability based on depth and diameter of the flat-bottom holes were defined for each composite material. Ultrasonic and radiographic images of the samples were obtained and compared with the thermographic images.
Roth, Don J.; Bodis, James R.; Bishop, Chip
Cross-talk free image encryption and watermarking by digital holography and random composition
NASA Astrophysics Data System (ADS)
In previous image watermarking methods an encoded host image and a watermark image are usually directly added, consequently the two images have cross-talk in the decryption step. To eliminate this effect, we propose a novel method based on digital holography, in which all the image pixels of the two sets of holograms resulted from two hidden images are rearranged and integrated into one set of composite holograms with a random scattering matrix (RSM). In decryption the use of this matrix can ensure the exact retrieval of each hologram, and then the perfect reconstruction of each image without cross-talk noise can be achieved. The feasibility of this method and its robustness against occlusion and additional noise are verified by computer simulations with phase-shifting interferometry and double random-phase encoding technique. This approach is suitable for both two- and three-dimensional images, and the additional RSM as a key provides a much higher level of security.
Meng, X. F.; Cai, L. Z.; He, M. Z.; Dong, G. Y.; Shen, X. X.
Colour annealing - a toy model of colour reconnections
We present a simple toy model for colour reconnections at the nonperturbative level. The model resembles an annealing-type algorithm and is applicable to any collider and process type, though we argue for a possible enhancement of the effect in hadron-hadron collisions. We present a simple application and study of the consequences for semileptonic t{bar t} events at the Tevatron.
Sandhoff, Marisa; /Wuppertal U.; Skands, Peter; /Fermilab
Effect of spatial uncertainty and familiarity on memory for surface colour in natural scenes and Mondrian patterns
How does memory affect surface-colour matching and is there any advantage with familiar scenes? A computer- controlled colour display system was used to present images of natural scenes and Mondrian patterns under two different daylights of correlated colour temperatures 25000 K and 6500 K, each lasting 1 s and separated by an interval lasting 0, 0.1, 0.2, 0.5, 1, 2,
Kinjiro Amano; David H. Foster
A Lantern for lesting Colour-Vision is arranged to show test colours in pairs as in the Board of Trade Lantern. It is adapted to use electric light, and is standardized by stringent testing. The paper discusses the experiments and considerations which led to the formulation of the allowable tolerances in the transmission and colour co-ordinate specifications of the filters, the colour temperature of the lamps and so on. The results of tests on normal and colour-defective subjects are described.
Martin, L. C.
Review of thermal imaging systems in composite defect detection
NASA Astrophysics Data System (ADS)
Thermal imaging technologies are widely used at present in many industrial areas, while being nowadays more and more employed in R&D&i activities. This article focuses on the comparison of the results obtained with commercially available non-experimental infrared (IR) cameras in the field of non-destructive defect detection. One of the cameras belongs to the FLIR SC5000 series, which is a Medium Wavelength Infrared (MWIR) camera, and the other two cameras are from the high-end ImageIR series manufactured by InfraTec GmbH: the ImageIR 8300 also belongs to the class of MWIR cameras and the ImageIR 8800 is a Long Wavelength Infrared (LWIR) camera. The comparative study is carried out by means of inspecting three different calibrated and induced defect samples with these three cameras using similar excitation sources, so that the configuration and lay out of the tests are comparable with each other. Additionally, after every inspection, a mathematical post-processing is applied to the resulting raw thermal images in order to enhance the detection of defects present in the samples.
Jorge Aldave, I.; Venegas Bosom, P.; Vega Gonz�lez, L.; L�pez de Santiago, I.; Vollheim, B.; Krausz, L.; Georges, M.
Going Beyond RGB: How to Create Color Composite Images that Convey the Science
NASA Astrophysics Data System (ADS)
The quality of modern astronomical data and the agility of current image-processing software enable new ways to visualize data as images. Two developments in particular have led to a fundamental change in how astronomical images may be assembled. First, the availability of high-quality multiwavelength and narrowband data allow for images that do not correspond to the wavelength sensitivity of the human eye, thereby introducing ambiguity in the usage and interpretation of color. Second, many image-processing software packages now use a layering metaphor that allows for any number of astronomical datasets to be combined into a color composite image. Furthermore, any color may be assigned to each dataset, not just red, green or blue. With this technique, images with as many as eight datasets have been produced. Each dataset is intensity scaled and colorized independently, creating an immense parameter space that may be used to assemble the image. Since such images are intended for data visualization, scaling and color schemes must be chosen that best illustrate the science. I will demonstrate how color composite images can be assembled in Photoshow and GIMP. I will also give examples of how color can be effectively used to convey the science of interest.
Rector, Travis A.; Levay, Z. G.; Frattare, L. M.; English, J.; Pu'uohau-Pummill, K.
Colour doppler ultrasonography provides real-time microwave field visualisation in an ex vivo porcine model
Introduction Microwave ablation (MWA) uses non-ionising thermal energy to cause cell death by coagulative necrosis. Colour Doppler ultrasound (US) produces a spherical image during tissue ablation that appears to approximate the microwave near field (MNF) in shape and size. The aim of the present study was to determine whether colour Doppler US images observed during microwave ablation correlate with the actual thermocoagulation zone (TCZ) observed in liver tissue. Methods Twenty MWAs were performed in ex vivo bovine liver using a 915-MHz ablation antenna set to 45 W for 6 min concomitant with Doppler US imaging. The edges of spherical images observed with colour Doppler US were marked circumferentially in the tissue. The tissue was transected parallel to the angle of antenna insertion, and the distances between methylene blue markings and the TCZ were measured. Results The images observed using colour Doppler US were similar in size and shape to the actual TCZ observed in the tissue. The mean distance between the observed colour Doppler US field diameter and the measured TCZ was 2 � 1 mm. Conclusions Using colour Doppler US, the visualised field during MWA correlates with the TCZ in an ex vivo bovine liver model. Real-time, dynamic feedback of the treatment area may increase the effectiveness of MWA for liver tumours in vivo.
Byrd, Jim F; Agee, Neal; McKillop, Iain H; Sindram, David; Martinie, John B; Iannitti, David A
On auroral electron precipitation and colour ratios
NASA Astrophysics Data System (ADS)
Auroral electron precipitation spectra can be retrieved from several complementary techniques, either ground-based or satellite. They include for example inversions of electron density profiles (measured for instance by incoherent scatter radars, IS), inversions of volume emission rate profiles (optical instruments), and the use of multi-spectral imaging in combination with ionospheric modelling (optical emission ratios). This study investigates several well-known colour ratios in discrete aurorae at Earth, such as N2+ 391.4 nm / 427.8 nm or O2+ 5620 / OI 777.4 nm, in order to determine the uncertainties of these inversion techniques. Their theoretical dependence to parameters such as the neutral atmosphere, the electron precipitation distribution and the cross section is presented. In a second step, comparison of these simulations with real data is proposed. The multi-spectral multi-station Auroral Large Imaging System (ALIS) was operated in March 2008 in Northern Scandinavia during a joint campaign with the EISCAT UHF radar in Tromso. Colour ratios, such as OI 844.6 nm / N2+ 427.8 nm and OI 630.0 nm / N2+ 427.8 nm, observed nearly simultaneously, are extracted and give access to the characteristic energy of the precipitation. They are shown to be consistent with electron spectra retrieved by IS radar. Perspectives are given for planetary studies, for which a global view of electron precipitation mechanisms and their impact on the atmosphere is needed to complement the limited number of observations and instruments aboard planetary space missions.
Simon Wedlund, C.; Gronoff, G.; Mertens, C. J.; Lamy, H.; Gustavsson, B.
The influence of colour and sound on neuronal activation during visual object naming
This paper investigates how neuronal activation for naming photographs of objects is influenced by the addition of appropriate colour or sound. Behaviourally, both colour and sound are known to facilitate object recognition from visual form. However, previous functional imaging studies have shown inconsistent effects. For example, the addition of appropriate colour has been shown to reduce antero-medial temporal activation whereas the addition of sound has been shown to increase posterior superior temporal activation. Here we compared the effect of adding colour or sound cues in the same experiment. We found that the addition of either the appropriate colour or sound increased activation for naming photographs of objects in bilateral occipital regions and the right anterior fusiform. Moreover, the addition of colour reduced left antero-medial temporal activation but this effect was not observed for the addition of object sound. We propose that activation in bilateral occipital and right fusiform areas precedes the integration of visual form with either its colour or associated sound. In contrast, left antero-medial temporal activation is reduced because object recognition is facilitated after colour and form have been integrated.
Hocking, Julia; Price, Cathy J.
Micromachined PIN-PMN-PT crystal composite transducer for high-frequency intravascular ultrasound (IVUS) imaging.
In this paper, we report the use of micromachined PbIn1/2Nb1/2O3-PbMg1/3Nb2/3O3-PbTiO 3 (PIN-PMNPT) single crystal 1-3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 ?m axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PTbased composite and its thermal stability is higher than PMNPT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMNPT. PMID:24960706
Li, Xiang; Ma, Teng; Tian, Jian; Han, Pengdi; Zhou, Qifa; Shung, K
Research of processing method for infrared image of sandwich structure composite
NASA Astrophysics Data System (ADS)
Composite sandwich structure has been widely used in aerospace due to its lightweight, high stiffness and strength. Existence of delaminations in the structure reduce the performance of the composites significantly, such flaws can be detected effectively and non-destructively by non-contact pulsed infrared thermography, but the contrast of infrared images of the material is low due to complex structure, so delaminations and sound area are difficult to be differentiated. In this paper, sandwich structure composites with aluminum facesheet and aluminum honeycomb cores are chosen as study objectives, several round-shape and rectangle-shape Teflon inserts with different sizes embedded in specimen, which simulate delaminations in the structure, and the processing method of infrared image is developed. The thermal image is processed through image denoising, image enhancement and feature extraction, and then the sizes of the defects are determined. Refer to the designed sizes, the results show that the accuracy of sizes measured by image processing is more than 90% for the defects bigger than ?10mm , these results demonstrated that detecting accuracy of the structure is higher by infrared image processing.
Huo, Yan; Zhang, Cun-Lin; Hu, Chun-Yu; Li, Chun-Guang
High Frequency PMN-PT 1-3 Composite Transducer for Ultrasonic Imaging Application
Development of PMN-PT single crystal/epoxy 1�3 composites for high-frequency ultrasonic transducers application is presented. The composite was fabricated by using a DRIE dry etching process with a 45% volume fraction of PMN-PT. A 35 MHz ultrasound flat transducer was fabricated with the composite, which was found to have an effective electromechanical coupling coefficient of 0.81, an insertion loss of 18 db, and a �6 dB bandwidth as high as 100%. Tungsten wire phantom image shows that the transducer had an axial resolution of 30 ?m, which was in good agreement with the theoretical expectation. The initial results showed that the PMN-PT/epoxy 1�3 composite has many attractive properties over conventional piezoelectric materials for medical imaging applications.
Composition of a Dewarped and Enhanced Document Image From Two View Images
In this paper, we propose an algorithm to compose a geometrically dewarped and visually enhanced image from two document images taken by a digital camera at different angles. Unlike the conventional works that require special equipments or assumptions on the contents of books or complicated image acquisition steps, we estimate the unfolded book or document surface from the corresponding points
Hyung il Koo; Jinho Kim; Nam Ik Cho
The original colours of fossil beetles
Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.
McNamara, Maria E.; Briggs, Derek E. G.; Orr, Patrick J.; Noh, Heeso; Cao, Hui
Development of a 35MHz piezo-composite ultrasound array for medical imaging
This paper discusses the development of a 64-element 35-MHz composite ultrasonic array. This array was designed primarily for ocular imaging applications, and features 2-2 composite elements mechanically diced out of a fine-grain high-density Navy Type VI ceramic. Array elements were spaced at a 50-micron pitch, interconnected via a custom flexible circuit and matched to the 50-ohm system electronics via a
Jonathan M. Cannata; Jay A. Williams; Qifa Zhou; Timothy A. Ritter; K. Kirk Shung
One-sided infrared thermal imaging for flaw characterization of ceramic matrix composites
One-sided infrared thermal imaging is being used to characterize voids and delamination in SiC/SiC composites. Flaw depth is estimated by examining the decay of surface temperature after application of a thermal pulse. Digital analysis of the surface temperature/time relationship allows characterization of the sizes and positions of defects. Results show that defects of various sizes and depths can be characterized in SiC/SiC composites with the technique.
Deemer, C.; Sun, J. G.; Ellingson, W. A.
Brilliant Star in a Colourful Neighbourhood
NASA Astrophysics Data System (ADS)
A spectacular new image from ESO's Wide Field Imager at the La Silla Observatory in Chile shows the brilliant and unusual star WR 22 and its colourful surroundings. WR 22 is a very hot and bright star that is shedding its atmosphere into space at a rate many millions of times faster than the Sun. It lies in the outer part of the dramatic Carina Nebula from which it formed. Very massive stars live fast and die young. Some of these stellar beacons have such intense radiation passing through their thick atmospheres late in their lives that they shed material into space many millions of times more quickly than relatively sedate stars such as the Sun. These rare, very hot and massive objects are known as Wolf-Rayet stars [1], after the two French astronomers who first identified them in the mid-nineteenth century, and one of the most massive ones yet measured is known as WR 22. It appears at the centre of this picture, which was created from images taken through red, green and blue filters with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. WR 22 is a member of a double star system and has been measured to have a mass at least 70 times that of the Sun. WR 22 lies in the southern constellation of Carina, the keel of Jason's ship Argo in Greek mythology. Although the star lies over 5000 light-years from the Earth it is so bright that it can just be faintly seen with the unaided eye under good conditions. WR 22 is one of many exceptionally brilliant stars associated with the beautiful Carina Nebula (also known as NGC 3372) and the outer part of this huge region of star formation in the southern Milky Way forms the colourful backdrop to this image. The subtle colours of the rich background tapestry are a result of the interactions between the intense ultraviolet radiation coming from hot massive stars, including WR 22, and the vast gas clouds, mostly hydrogen, from which they formed. The central part of this enormous complex of gas and dust lies off the left side of this picture as can be seen in image eso1031b. This area includes the remarkable star Eta Carinae and was featured in an earlier press release (eso0905). Notes [1] More information about Wolf-Rayet stars More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".
MERIS-based ocean colour classification with the discrete Forel-Ule scale
NASA Astrophysics Data System (ADS)
Multispectral information from satellite borne ocean colour sensors is at present used to characterize natural waters via the retrieval of concentration of the three dominant optical constituents; pigments of phytoplankton, non-algal particles and coloured dissolved organic matter. A limitation of this approach is that accurate retrieval of these constituents requires detailed local knowledge of the specific absorption and scattering properties. In addition, the retrieval algorithms generally use only a limited part of the collected spectral information. In this paper we present an additional new algorithm that has the merit to use the full spectral information in the visible domain to characterize natural waters in a simple and globally valid way. This Forel-Ule MERIS (FUME) algorithm converts the normalized multi-band reflectance information into a discrete set of numbers using uniform colourimetric functions. The Forel-Ule scale is a sea colour comparator scale that has been developed to cover all possible natural sea colours, ranging from indigo blue (the open ocean) to brownish-green (coastal water) and even brown (humic-acid dominated) waters. Data using this scale have been collected since the late nineteenth century, and therefore, this algorithm creates the possibility to compare historic ocean colour data with present-day satellite ocean colour observations. The FUME algorithm was tested by transforming a number of MERIS satellite images into Forel-Ule colour index images and comparing in situ observed FU numbers with FU numbers modelled from in situ radiometer measurements.
Wernand, M. R.; Hommersom, A.; van der Woerd, H. J.
Preparation of AlB sub 4 C composites for image analysis
Composites made by infiltrating B{sub 4}C networks with aluminium, or its alloys are of interest for lightweight armor applications. Image analysis plays an important part in correlating the microstructures of such composites with their mechanical properties. Accurate image analysis requires a high degree of perfection in the metallographic preparation, which is particularly difficult where the phases present have such disparate hardness and reactivities. Two preparation procedures have been developed that produce adequate contrast and definition for analysis of key microstructural features. 8 refs., 5 figs., 1 tab.
Kelly, A.M.; Reiswig, R.D.; Hill, M.A.; Blumenthal, W.R.
Characterization of delamination and disbonding in stratified dielectric composites by millimeter wave imaging
Electromagnetic radiation at microwave frequencies has been in use for nondestructive evaluation (NDE) of various low-loss and generally lossy dielectric materials. A monostatic backscatter millimeter wave imaging system was utilized for non-destructive characterization of defects in low-loss composites of Kevlar/epoxy. Defects consisting of subsurface delamination and disbonding defects were successfully detected and characterized. Images are constructed by measuring the relative amplitude and phase of the reflected radiation. The results clearly indicate the potential of such high-frequency systems for nondestructive characterization of small defects in low-loss dielectric composite materials.
Bakhtiari, S.; Gopalsami, N.; Raptis, A.C. [Argonne National Lab., IL (United States). Energy Technology Division
True and false memory for colour names versus actual colours: support for the visual distinctiveness heuristic in memory for colour information.
In a colour variation of the Deese-Roediger-McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., "blood, cherry, scarlet, rouge ... "); they later showed false memory for the critical colour name (e.g., "red"). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis. PMID:19941197
Eslick, Andrea N; Kostic, Bogdan; Cleary, Anne M
Roles of biologic breast tissue composition and quantitative image analysis of mammographic images in breast tumor characterization
NASA Astrophysics Data System (ADS)
Purpose. Investigate whether knowledge of the biologic image composition of mammographic lesions provides imagebased biomarkers above and beyond those obtainable from quantitative image analysis (QIA) of X-ray mammography. Methods. The dataset consisted of 45 in vivo breast lesions imaged with the novel 3-component breast (3CB) imaging technique based on dual-energy mammography (15 malignant, 30 benign diagnoses). The 3CB composition measures of water, lipid, and protein thicknesses were assessed and mathematical descriptors, `3CB features', were obtained for the lesions and their periphery. The raw low-energy mammographic images were analyzed with an established in-house QIA method obtaining `QIA features' describing morphology and texture. We investigated the correlation within the `3CB features', within the `QIA features', and between the two. In addition, the merit of individual features in the distinction between malignant and benign lesions was assessed. Results. Whereas many descriptors within the `3CB features' and `QIA features' were, often by design, highly correlated, correlation between descriptors of the two feature groups was much weaker (maximum absolute correlation coefficient 0.58, p<0.001) indicating that 3CB and QIA-based biomarkers provided potentially complementary information. Single descriptors from 3CB and QIA appeared equally well-suited for the distinction between malignant and benign lesions, with maximum area under the ROC curve 0.71 for a protein feature (3CB) and 0.71 for a texture feature (QIA). Conclusions. In this pilot study analyzing the new 3CB imaging modality, knowledge of breast tissue composition appeared additive in combination with existing mammographic QIA methods for the distinction between benign and malignant lesions.
Drukker, Karen; Giger, Maryellen L.; Duewer, Fred; Malkov, Serghei; Flowers, Christopher I.; Joe, Bonnie; Kerlikowske, Karla; Drukteinis, Jennifer S.; Shepherd, John
Damage threshold study of sonic IR imaging on carbon-fiber reinforced laminated composite materials
NASA Astrophysics Data System (ADS)
Sonic Infrared Imaging, as a young NDE technology, has drawn a lot of attentions due to it's fast, wide-area evaluation capability, and due to its broad applications in different materials such as metal/metal alloy, composites and detection of various types of defects: surface, subsurface, cracks, delaminations/disbonds. Sonic IR Imaging combines pulsed ultrasound excitation and infrared imaging to detect defects in materials. The sound pulse causes rubbing due to non-unison motion between faces of defects, and infrared sensors image the temperature map over the target to identify defects. However, concerns have also been brought up about possible damages which might occur at the contact spots between the ultrasound transducer from the external excitation source and the target materials. In this paper, we present our results from a series of systematically designed experiments on carbon-fiber reinforced laminated composite panels to address the concerns.
Han, Xiaoyan; He, Qi; Zhang, Ding; Ashbaugh, Mike; Favro, Lawrence D.; Newaz, Golam; Thomas, Robert L.
A novel Bayesian imaging method for probabilistic delamination detection of composite materials
NASA Astrophysics Data System (ADS)
A probabilistic framework for location and size determination for delamination in carbon-carbon composites is proposed in this paper. A probability image of delaminated area using Lamb wave-based damage detection features is constructed with the Bayesian updating technique. First, the algorithm for the probabilistic delamination detection framework using the proposed Bayesian imaging method (BIM) is presented. Next, a fatigue testing setup for carbon-carbon composite coupons is described. The Lamb wave-based diagnostic signal is then interpreted and processed. Next, the obtained signal features are incorporated in the Bayesian imaging method for delamination size and location detection, as well as the corresponding uncertainty bounds prediction. The damage detection results using the proposed methodology are compared with x-ray images for verification and validation. Finally, some conclusions are drawn and suggestions made for future works based on the study presented in this paper.
Peng, Tishun; Saxena, Abhinav; Goebel, Kai; Xiang, Yibing; Sankararaman, Shankar; Liu, Yongming
A composite six bp in-frame deletion in the melanocortin 1 receptor (MC1R) gene is associated with the Japanese brindling coat colour in rabbits (Oryctolagus cuniculus)
Background In the domestic rabbit (Oryctolagus cuniculus), classical genetic studies have identified five alleles at the Extension locus: ED (dominant black), ES (steel, weaker version of ED), E (wild type, normal extension of black), eJ(Japanese brindling, mosaic distribution of black and yellow) and e (non-extension of black, yellow/red with white belly). Sequencing almost the complete coding sequence (CDS) of the rabbit MC1R gene, we recently identified two in-frame deletions associated with dominant black (c.280_285del6; alleles ED or ES) and recessive red (c.304_333del30; allele e) coat colours. It remained to characterize the eJallele whose phenotypic effect is similar to the Orange and Sex-linked yellow loci of cat and Syrian hamster. Results We sequenced the whole CDS in 25 rabbits of different coat colours including 10 Japanese and 10 Rhinelander (tricolour) rabbits and identified another 6 bp-in frame deletion flanked by a G > A transition in 5' (c.[124G>A;125_130del6]) that was present in all animals with Japanese brindling coat colour and pattern. These mutations eliminate two amino acids in the first transmembrane domain and, in addition, cause an amino acid substitution at position 44 of the wild type sequence. Genotyping 371 rabbits of 31 breeds with different coat colour this allele (eJ) was present in homozygous state in Japanese, Rhinelander and Dutch tricolour rabbits only (except one albino rabbit). Rabbits with eJ/eJ genotype were non fixed at the non-agouti mutation we previously identified in the ASIP gene. Segregation in F1 and F2 families confirmed the order of dominance already determined by classical genetic experiments with a possible dose effect evident comparing eJ/eJ and eJ/e animals. MC1R mRNA was expressed in black hair skin regions only. Conclusions The c.[124A;125_130del6] allele may be responsible for a MC1R variant determining eumelanin production in the black areas. However, the mechanism determining the presence of both red and black hairs in the same animal seems more complex. Expression analyses of the c.[124A;125_130del6] allele suggest that MC1R transcription may be regulated epigenetically in rabbits with the Japanese brindling phenotype. Further studies are needed to clarify this issue.
Synchrotron X-ray nanomechanical imaging of mineralized fiber composites.
In situ synchrotron X-ray scattering and diffraction, in combination with micromechanical testing, can provide quantitative information on the nanoscale mechanics of biomineralized composites, such as bone, nacre, and enamel. Due to the hierarchical architecture of these systems, the methodology for extraction of mechanical parameters at the molecular and supramolecular scale requires special considerations regarding design of mechanical test apparatus, sample preparation and testing, data analysis, and interpretation of X-ray structural information in terms of small-scale mechanics. In this chapter, this methodology is described using as a case study the deformation mechanisms at the fibrillar and mineral particle level in cortical bone. Following a description of the sample preparation, testing, and analysis procedures for bone in general, two applications of the method-to understand fibrillar-level mechanics in tension and bending in a mouse model of rachitic disease-are presented, together with a discussion of how to relate in situ scattering and diffraction data acquired during mechanical testing to nanostructural models for deformation of biomineralized composites. PMID:24188778
Karunaratne, Angelo; Terrill, Nicholas J; Gupta, Himadri S
A 30MHz piezo-composite ultrasound array for medical imaging applications
Ultrasound imaging at frequencies above 20 MHz is capable of achieving improved resolution in clinical applications requiring limited penetration depth. High frequency arrays that allow real-time imaging are desired for these applications but are not yet currently available. In this work, a method for fabricating fine-scale 2-2 composites suitable for 30-MHz linear array transducers was successfully demonstrated. High thickness coupling,
Timothy A. Ritter; Thomas R. Shrout; Rick Tutwiler; K. Kirk Shung
Image correlation nondestructive evaluation of impact damage in a glass fiber composite
NASA Technical Reports Server (NTRS)
Presented in viewgraph format, digital image correlation, damage in fibrous composites, and damaged coupons (cross-ply scotchply GI-Ep laminate) are outlined. It was concluded that the image correlation accuracy was 0.03 percent; strains can be processed through Tsai-Hill failure criteria to qualify the damage; the statistical data base must be generated to evaluate certainty of the damage estimate; size effects need consideration; and better numerical techniques are needed.
Russell, Samuel S.
Representing object colour in language comprehension.
Embodied theories of cognition hold that mentally representing something red engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task performance. After reading a sentence that implied a particular colour for a given object, participants were presented with a picture of the object that either matched or mismatched the implied colour. When asked if the pictured object was mentioned in the preceding sentence, people's responses were faster when the colours mismatched than when they matched, suggesting that object colour is represented differently to other object properties such as shape and orientation. A distinction between stable and unstable embodied representations is proposed to allow embodied theories to account for these findings. PMID:16616075
Connell, Louise
Colour Consideration for Waiting areas in hospitals
NASA Astrophysics Data System (ADS)
Colour is one the most important factors in the nature that can have some affects on human behaviour. Many years ago, it was proven that using colour in public place can have some affect on the users. Depend of the darkness and lightness; it can be vary from positive to negative. The research will mainly focus on the colour and psychological influences and physical factors. The statement of problem in this research is what is impact of colour usually applied to waiting area? The overall aim of the study is to explore the visual environment of hospitals and to manage the colour psychological effect of the hospital users in the waiting area by creating a comfortable, pleasant and cozy environment for users while spend their time in waiting areas. The analysisconcentrate on satisfaction and their interesting regarding applied colour in two private hospital waiting area in Malaysia.
Zraati, Parisa
Composite low-coherence interferometer for imaging of immersed tissue with high accuracy
NASA Astrophysics Data System (ADS)
Imaging and measurement of the surface profile of an object with high resolution has become essential in both of biological research and industry application. Many samples under investigation such as cultured cells are usually immersed in liquid. Although the techniques such as scanning electron microscope and atomic force microscope can provide imaging or measurement of the surface profile with nanometer resolution, it is difficult for them to image an immersed object with their typical types. Recently, we have proposed and demonstrated a new technique based on composite interferometer which can perform imaging and measurement of the surface profile of an object with accuracy in the axial direction within 5 nm through a self-phase-compensation mechanism. In this research, an optical system based on the concept of combination of optical coherence microscopy (OCM) and composite interferometer was built for imaging of biological tissue immersed in water with axial accuracy at nanometer scale. In the system, a Ti:sapphire laser with center wavelength at 800 nm and spectral width of 140 nm was used as the light source. The composite interferometer comprises two Michelson interferometers sharing common light source, reference arm and photodetector. One of the two interferometers served as a typical OCM system and the other was used to measure the phase shift in the reference arm in each axial scan with the sample being a fixed reflection mirror. The system was used to image the surface profiles of various immersed biological samples with accuracy at nanometer scale through the self-phasecompensation mechanism.
Chang, Chun-Wei; Hsu, I.-Jen
Colour-independent partition functions in coloured vertex models
NASA Astrophysics Data System (ADS)
We study lattice configurations related to Sn, the scalar product of an off-shell state and an on-shell state in rational An integrable vertex models, n?{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric An models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S2 (Caetano and Vieira, 2012, [1], Wheeler, arXiv:1204.2089, [2]). Namely, 1.S2, which depends on two sets of Bethe roots, {b1} and {b2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b1}??, and/or {b2}??, into a product of determinants, 2. Each of the latter determinants is an A1 vertex-model partition function.
Foda, O.; Wheeler, M.
True Color Images of the Earth created with the Geostationary Satellite Instrument MSG SEVIRI
NASA Astrophysics Data System (ADS)
One of the most famous pictures ever taken was by the crew of Apollo 17 in 1972, showing our Earth from a distance of about 45000km. This picture was named 'Blue Marble' and it reminds us of the beauty and uniqueness of our home planet. With geostationary satellites, such views of the Earth are possible without the need to have a photographer in space. However, up to the present, the production of such Blue Marble type images from geostationary satellite data has been impaired by the lack of channels in the visible spectral region. A method for the generation of full disk MSG (METEOSAT Second Generation) SEVIRI (Scanning-Enhanced Visible and Infrared Imager) true colour composite images will be presented. The algorithm mainly uses the SEVIRI channels VIS006 (0.6?m), NIR008 (0.8?m) and NIR016 (1.6?m). The lack of information in the blue and green parts of the visible spectrum is compensated by using data from NASA's (National Aeronautics and Space Administration's) Blue Marble next generation (BMNG) project to fill a look-up table (LUT) transforming RGB (red/green/blue) false colour composite images of VIS006/NIR008/NIR016 into true colour images. Tabulated radiative transfer calculations of a pure Rayleigh atmosphere are used to add an impression of Rayleigh scattering towards the sunlit horizon. The resulting images satisfy naive expectations: clouds are white or transparent, vegetated surfaces are greenish, deserts are sandy-coloured, the ocean is dark blue to black and a narrow halo due to Rayleigh scattering is visible at the sunlit horizon. Therefore, such images are easily interpretable also for inexperienced users not familiar with the characteristics of typical MSG false colour composite images. The images can be used for scientific applications to illustrate specific meteorological conditions or for non-scientific purposes, for example, for raising awareness in the public of the Earth's worthiness of protection.
Reuter, Maximilian
Geometric and Colour Data Fusion for Outdoor 3D Models
This paper deals with the generation of accurate, dense and coloured 3D models of outdoor scenarios from scanners. This is a challenging research field in which several problems still remain unsolved. In particular, the process of 3D model creation in outdoor scenes may be inefficient if the scene is digitalized under unsuitable technical (specific scanner on-board camera) and environmental (rain, dampness, changing illumination) conditions. We address our research towards the integration of images and range data to produce photorealistic models. Our proposal is based on decoupling the colour integration and geometry reconstruction stages, making them independent and controlled processes. This issue is approached from two different viewpoints. On the one hand, given a complete model (geometry plus texture), we propose a method to modify the original texture provided by the scanner on-board camera with the colour information extracted from external images taken at given moments and under specific environmental conditions. On the other hand, we propose an algorithm to directly assign external images onto the complete geometric model, thus avoiding tedious on-line calibration processes. We present the work conducted on two large Roman archaeological sites dating from the first century A.D., namely, the Theatre of Segobriga and the Fori Porticus of Emerita Augusta, both in Spain. The results obtained demonstrate that our approach could be useful in the digitalization and 3D modelling fields.
Merchan, Pilar; Adan, Antonio; Salamanca, Santiago; Dominguez, Vicente; Chacon, Ricardo
Chick colour approach preferences are altered by cold stress; colour pecking and approach preferences are the same.
Colour approach preferences in 1-day-old New Hampshire and White Leghorn chicks were assessed by choice preference tests between pairs of differently coloured floors, illuminated by light passed through different interference filters and adjusted to equal luminance. In experiment 1, the preferences found closely resembled colour pecking preferences reported previously for domestic chicks, e.g. a preference for blue over green. Experiment 2 showed that the latter preference could be reversed by cold stress. That is, chicks tested similarly but in a cold noisy room (18.9 C) preferred green over blue. Experiment 3 eliminated the role of noise in this reversal effect, since chicks tested in a warm noisy room showed the normal blue over green preference. It was concluded, in disagreement with prior findings and their interpretations, that chick colour pecking and approach preferences are normally the same, not different, and certainly not spectral mirror-image reversals. Instead, a more restricted preference reversal (i.e. in the blue-green spectral regions) occurs as a result of cold stress. PMID:565177
Davis, S J; Fischer, G J
Simultaneously measuring 3D shape and colour texture of moving objects using IR and colour fringe projection techniques
NASA Astrophysics Data System (ADS)
Simultaneously measuring the three-dimensional (3D) shape and colour texture of moving objects in real time is becoming increasingly important in many application fields. The existing methods of measuring moving objects have certain disadvantages, such as complicated procedures to build the coordinate transformation between cameras, inaccurate 3D shape data because of the longer capturing time of fringe pattern images, and sensitivity to environmental light due to the projected visible fringe patterns. This paper presents a novel method to capture 3D shape and colour texture information of moving objects simultaneously by combining the infrared (IR) channel and visible channel together. Shape data are calculated from IR fringe patterns to avoid the effect of environmental light on the measured objects. Shape data and colour texture information are simultaneously captured by IR and visible channels of a 2-CCD camera; therefore, these parameters have pixel-to-pixel correspondence without needing any registration. The experimental results on two moving objects indicate that the proposed method can simultaneously obtain 3D shape and colour texture information in a reliable way.
Xu, Y. J.; Chen, C.; Huang, S. J.; Zhang, Z. H.
Colour-space distortion in women who are heterozygous for colour deficiency.
We examined colour perception among a group of women heterozygous for colour vision deficiency. Judgements of colour dissimilarity were collected by presenting colour stimuli in groups of three for odd-one-out decisions. The judgements were summarised as one consensus colour space for the heterozygotes and another for age-matched controls. Individual differences MDS was also applied, resulting in a single colour space which can be adjusted to fit each subject's responses individually by compressing it along its axes. Heterozygous women showed a trend towards colour-space compression in a red-green dimension, or reduced salience of that dimension compared to controls, though less extreme than found in overt colour deficiency. PMID:19167418
Bimler, David; Kirkland, John
Gas Flow Measurements by 3D Particle Tracking Velocimetry Using Coloured Tracer Particles
This work describes an original approach for 3D�Particle Tracking Velocimetry (3D�PTV), applicable also for gaseous flows\\u000a and based on tracer particles of different colours. On the images acquired by several cameras, tracer particles are handled\\u000a by colour recognition and 3D localisation. Then, the PTV tracking algorithm rebuilds the trajectories of the tracer particles\\u000a using a criterion of Minimum Acceleration. Theoretical
Dominique Tarlet; Christian Bendicks; Christoph Roloff; R�bert Bord�s; Bernd Wunderlich; Bernd Michaelis; Dominique Th�venin
Colour Gradients in Clusters of Galaxies
NASA Astrophysics Data System (ADS)
We investigate the environmental effects (interactions/mergers, ram preasure stripping) in clusters of galaxies by means of colour gradients. These effects affect the photometrical properties of clusters, enhancing the fraction of blue galaxies (Butcher-Oemler effect). In this paper we determine the colour gradients frac{d(B-V)}{dR} in 13 clusters of galaxies, with redshifts 0.198 < = z < = 0.81, and investigate their cosmological dependence. The problem of colour evolution of galaxies in clusters, the connexion between the colour gradients and the Butcher-Oemler effect are also discussed.
Suran, M. D.; Popescu, N. A.
How temporal cues can aid colour constancy
Colour constancy assessed by asymmetric simultaneous colour matching usually reveals limited levels of performance in the unadapted eye. Yet observers can readily discriminate illuminant changes on a scene from changes in the spectral reflectances of the surfaces making up the scene. This ability is probably based on judgements of relational colour constancy, in turn based on the physical stability of spatial ratios of cone excitations under illuminant changes. Evidence is presented suggesting that the ability to detect violations in relational colour constancy depends on temporal transient cues. Because colour constancy and relational colour constancy are closely connected, it should be possible to improve estimates of colour constancy by introducing similar transient cues into the matching task. To test this hypothesis, an experiment was performed in which observers made surface-colour matches between patterns presented in the same position in an alternating sequence with period 2 s or, as a control, presented simultaneously, side-by-side. The degree of constancy was significantly higher for sequential presentation, reaching 87% for matches averaged over 20 observers. Temporal cues may offer a useful source of information for making colour-constancy judgements.
Foster, David H.; Amano, Kinjiro; Nascimento, Sergio M. C.
Plexus structure imaging with thin slab MR neurography: rotating frames, fly-throughs, and composite projections
NASA Astrophysics Data System (ADS)
We explored multiple image processing approaches by which to display the segmented adult brachial plexus in a three-dimensional manner. Magnetic resonance neurography (MRN) 1.5-Tesla scans with STIR sequences, which preferentially highlight nerves, were performed in adult volunteers to generate high-resolution raw images. Using multiple software programs, the raw MRN images were then manipulated so as to achieve segmentation of plexus neurovascular structures, which were incorporated into three different visualization schemes: rotating upper thoracic girdle skeletal frames, dynamic fly-throughs parallel to the clavicle, and thin slab volume-rendered composite projections.
Raphael, David T.; McIntee, Diane; Tsuruda, Jay S.; Colletti, Patrick; Tatevossian, Raymond; Frazier, James
Image Re-Composer: A Post-Production Tool Using Composition Information of Pictures
We propose a post-production tool for refining pictures called the Image Re-Composer. This tool decomposes an original picture into figure objects and the ground, and then recomposes the figure objects according to composition information taken from a well designed picture, such as an art masterpiece. The figure extraction is performed by a figure extraction method that utilizes a characteristic of
Shoji Tanaka; Jun Kurumizawa; Andre Plante; Yuichi Iwadate; Seiji Inokuchi
An image analysis technique for evaluating internal damage in graphite-fabric\\/polyimide composites
The purpose of this paper is to suggest a possible technique for evaluating internal damage in fabric-reinforced composite materials. The technique presented in this work is based on capturing and performing a qualitative analysis of scanning electron microscope (SEM) images of damage from planar specimen slices (serial sections) and then reassembling the slices in three-dimensional space. This method has been
K Searles; J McCarthy; M Kumosa
The influence of bonding agents in improving interactions in composite propellants determined using image analysis.
Binder-oxidizer interactions in rocket composite propellants can be improved using adequate bonding agents. In the present work, the effectiveness of different 1,3,5-trisubstituted isocyanurates was determined by stereo and metallographic microscopy and using the software package Image-Pro Plus. The chemical analysis of samples was performed by a scanning electron microscope equipped for energy dispersive spectrometry. PMID:19094035
Dostani?, J; Husovi?, T V; Us?umli?, G; Heinemann, R J; Mijin, D
Thermal imaging and air-coupled ultrasound characterization of a continuous-fiber ceramic composite panels.
SYLRAMIC{trademark} continuous fiber ceramic-matrix composites (Nicalon{trademark} fiber/SiNC matrix) were fabricated by Dow Corning Corporation with the polymer-impregnation and pyrolysis (PIP) process. The composite microstructure and its uniformity, and the completeness of infiltration during processing were studied as a function of number of PIP cycles. Two nondestructive evaluation (NDE) methods, i.e., infrared thermal imaging and air-coupled ultrasound (UT), were used to investigate flat composite panels of two thicknesses and various sizes. The thermal imaging method provided two-dimensional (2D) images of through-thickness thermal diffusivity distributions, and the air-coupled UT method provided 2D images of through-thickness ultrasonic transmission of the panel components. Results from both types of NDEs were compared at various PIP cycles during fabrication of the composites. A delaminated region was clearly detected and its progressive repair was monitored during processing. The NDE data were also correlated to results obtained from destructive characterization.
Sun, J. G.; Easler, T. E.; Szweda, A.; Pillai, T. A. K.; Deemer, C.; Ellingson, W. A.
Automatic mapping of surfaces affected by forest fires in Spain using AVHRR NDVI composite image data
In this work, we describe the statistical techniques used to analyze images from the National Oceanic and Atmospheric Administration's advanced very high resolution radiometer for the calculation and mapping of surfaces affected by large forest fires in Spain in 1993 and 1994. Maximum value normalized difference vegetation index (NDVI) composites (MVCs) were generated for every ten-day period over the two
Alberto Fern�ndez; Pilar Illera; Jose Luis Casanova
Can Imageability Help Us Draw the Line between Storage and Composition?
ERIC Educational Resources Information Center
Language requires both storage and composition. However, exactly what is retrieved from memory and what is assembled remains controversial, especially for inflected words. Here, "imageability effects" is introduced as a new diagnostic of storage and a complement to frequency effects. In 2 studies of past-tense morphology, more reliable�
Prado, Elizabeth L.; Ullman, Michael T.
On the colour contribution to effective weak vertex in broken colour gauge theories
Treating the breaking of colour symmetry via the mixing between the colour gluons and weak bosons (a la Rajasekaran and Roy)\\u000a it is observed that the colour contribution to the effective weak vertex of a quark at zero momentum transfer is zero uptoO(?).
R Ramachandran
BOREAS RSS-7 Regional LAI and FPAR Images From 10-Day AVHRR-LAC Composites
NASA Technical Reports Server (NTRS)
The BOReal Ecosystem-Atmosphere Study Remote Sensing Science (BOREAS RSS-7) team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of Leaf Area Index (LAI) from remotely sensed images. Advanced Very High Resolution Radiometer (AVHRR) level-4c 10-day composite Normalized Difference Vegetation Index (NDVI) images produced at CCRS were used to produce images of LAI and the Fraction of Photosynthetically Active Radiation (FPAR) absorbed by plant canopies for the three summer IFCs in 1994 across the BOREAS region. The algorithms were developed based on ground measurements and Landsat Thematic Mapper (TM) images. The data are stored in binary image format files.
Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing; Cihlar, Josef
Estimating the Number of Endmembers in Hyperspectral Images Using the Normal Compositional Model and a Hierarchical Bayesian Algorithm
This paper studies a semi-supervised Bayesian unmixing algorithm for hyperspectral images. This algorithm is based on the normal compositional model recently introduced by Eismann and Stein. The normal compositional model assumes that each pixel of the image is modeled as a linear combination of an unknown number of pure materials, called endmembers. However, contrary to the classical linear mixing model,
Olivier Eches; Nicolas Dobigeon; Jean-Yves Tourneret
Flaw Detection for Composite Materials Improved by Advanced Thermal Image Reconstruction Techniques
NASA Technical Reports Server (NTRS)
The development of advanced composite materials for use in space and propulsion components has seen considerable growth over the past few years. In addition to improvements that have been made in material properties and processing techniques, similar growth must be seen in the development of methods for the detection of flaws, either generated in service or during manufacturing. Thermal imaging techniques have proven to be successful for the nondestructive evaluation (NDE) of composite materials, but their detection capabilities decrease as flaw depth increases. The purpose of this research is to investigate advanced thermal imaging methods and thermal image processing technologies to increase the maximum depth below surface that a flaw can be detected and improve the contrast between flawed regions and sound regions.
Martin, Richard E.; Gyekenyesi, Andrew L.
Hierarchical test pattern composition to testing a foveal imager ASIC
NASA Astrophysics Data System (ADS)
The aim of this work is the test of an ASIC, intended for multiresolution images generation, with high fault coverage and low number of patterns, looking for the improvement of the results obtained with other tools. The circuit includes a embedded SRAM block used to implement several internal FIFO structures. This RAM block has been generated with the 'Memory Compiler Systems' supplied by AMS, and does not includes BIST logic, so the strategy was to generate and insert the BIST logic to completely test the RAM operation. The original test algorithm proposed by the foundry support center, has been modified for a thorough verification. Also, to achieve the controllability and observability of the shadow logic connected to the RAM outputs and inputs respectively, the necessary test logic around the embedded block has been inserted. Once the test of the RAM has been guaranteed the remaining logic needs to be tested. To accomplish this task the full scan path approach has been selected, and a hierarchical bottom-up methodology has been followed to generate the test patterns. The ATPG commercial tools ( Synopsys Test Compiler) has been used only to generate the patterns for the lowest level modules of the hierarchy tree. Making the appropriate design partitioning (basically defining the modules with registered outputs), the patterns for the upper level modules can be easily composed. Several appropriate configurations for this smart partitioning has been identified and defined. Using a simple composing technique we can obtain a considerable reduction above 37% in the number of patterns with a negligible fault coverage decrease and hardware overhead.
Gonzalez, Martin; Salinas, Jose R.; Coslado, Francisco J.; Camacho, Pelegrin; Sandoval, Francisco
Depth-Enhanced Integral Imaging with a Stepped Lens Array or a Composite Lens Array for Three-Dimensional Display
NASA Astrophysics Data System (ADS)
In spite of the many advantages of integral imaging, the depth of reconstructed three-dimensional (3D) image is limited to around the only one image plane. Here, we propose a novel method for increasing the depth of a reconstructed image using a stepped lens array (SLA) or a composite lens array (CLA). We confirm our idea by fabricating SLA and CLA with two image planes each. By using a SLA or a CLA, it is possible to form the 3D image around several image planes and to increase the depth of the reconstructed 3D image.
Choi, Heejin; Park, Jae-Hyeung; Hong, Jisoo; Lee, Byoungho
Colour-contingent after-effects are really wavelength-contingent.
McCollough reported that following adaptation to (say) a red and black pattern of vertical stripes, alternating every few seconds with a green and black pattern of horizontal stripes, an orientation-contingent colour after-effect is observed when black and white gratings are viewed. Vertical gratings are tinged with green and horizontal gratings with pink. We have exploited colour constancy, the tendency for objects to appear constant in hue despite large changes in the spectral composition of the illuminant, to examine whether the colours observed on the McCollough effect test gratings are determined by the wavelength composition of the adaptation patterns or by their perceived colour. The key to this approach can be illustrated by Edwin Land's elegant demonstrations of colour constancy using 'Mondrian' displays. By embedding the adapting grating that is used to induce the McCollough effect within a Mondrian we show that the effect depends upon the wavelength of light coming from the grating, rather than the perceived colour. PMID:3960135
Thompson, P; Latchford, G
Characterization of the interphase in carbon fiber\\/polymer composites using a nanoscale dynamic mechanical imaging technique
The interphase of fiber reinforced polymer composites is a narrow region around the fiber, and the mechanical performance of a composite strongly depends on the properties of the interphase. The interphase of carbon fiber reinforced polymer composites (CFRPs) is difficult to quantitatively characterize because of its nanometer dimension. To solve this problem, we present a nanomechanical imaging technique for mapping
Yizhuo Gu; Min Li; Ji Wang; Zuoguang Zhang
Characterization of impact damage in metallic/nonmetallic composites using x-ray computed tomography imaging
NASA Astrophysics Data System (ADS)
Characterizing internal impact damage in composites can be difficult, especially in structurally complex composites or those consisting of many materials. Many methods for nondestructive inspection/nondestructive testing (NDI/NDT) of materials have been known and in use for many years, including x-ray film, real-time, and digital radiographic techniques, and ultrasonic techniques. However, these techniques are generally not capable of three-dimensional (3D) mapping of complex damage patterns, which is necessary to visualize and understand damage cracking modes. Conventional x-ray radiography suffers from the loss of 3D information. Structural complexity and signal dispersion in materials with many interfaces significantly effect ultrasonic inspection techniques. This makes inspection scan interpretation difficult, especially in composites containing a number of different materials (i.e., polymer, ceramic, and metallic). X-ray computed tomography (CT) is broadly applicable to any material or test object through which a beam of penetrating radiation may be passed and detected, including metals, plastics, ceramics, metallic/nonmetallic composites, and assemblies. The principal advantage of CT is that it provides densitometric (that is, radiological density and geometry) images of thin cross sections through an object. Because of the absence of structural superposition, images are much easier to interpret than conventional radiological images. The user can quickly learn to read CT data because images correspond more closely to the way the human mind visualizes 3D structures than projection radiology (that is, film radiography, real-time radiography (RTR), and digital radiography (DR)). Any number of CT images, or slices, from scanning an object can be volumetrically reconstructed to produce a 3D attenuation map of the object. The 3D attenuation data can be rendered using multiplanar or 3D solid visualization. In multiplanar visualization there are four planes of view that can be defined to be anywhere in an object. These visualization modes produce easily interpretable images with very good spatial resolution and excellent dimensional capability. This paper will discuss current applications of advanced CT imaging to characterizing impact damage in metallic/nonmetallic composites. Examples, including encapsulated ceramics in metal-matrix-composites, will be discussed.
Green, William H.; Wells, Joseph M.
The Impact of Biochemistry vs. Population Membership on Floral Scent Profiles in Colour Polymorphic Hesperis matronalis
Background and Aims Studies of floral scent evolution often attribute variation in floral scent to differences in pollinator behaviour, ignoring the potential for shared biochemistry between floral scent and floral colour to dictate patterns of phenotypic variation in scent production. To determine the relative effects of shared biochemistry and/or localized population-level phenomena on floral scent phenotype, floral scent composition and emission rate were examined in five wild populations of colour polymorphic Hesperis matronalis (Brassicaceae). Methods Floral scent was collected by in situ dynamic headspace extraction on purple and white colour morphs in each of five wild populations. Gas chromatography�mass spectroscopy of extracts allowed determination of floral scent composition and emission rate for all individuals, which were examined by non-metric multidimensional scaling and analysis of variance (ANOVA), respectively, to determine the contributions of floral colour and population membership to scent profile variation. Key Results Despite the fact that colour morph means were very similar in some populations and quite different in other populations, colour morphs within populations did not differ from each other in terms of scent composition or emission rate. Populations differed significantly from one another in terms of both floral scent composition and emission rate. Conclusions Shared biochemistry alone cannot explain the variation in floral scent phenotype found for H. matronalis. Such a result may suggest that the biochemical association between floral scent and floral colour is complex or dependent on genetic background. Floral scent does vary significantly with population membership; several factors, including environmental conditions, founder effects and genetics, may account for this differentiation and should be considered in future studies.
Majetic, Cassie J.; Raguso, Robert A.; Ashman, Tia-Lynn
Colour mathematics: with graphs and numbers
NASA Astrophysics Data System (ADS)
The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just attempting to memorize them.
Lo Presto, Michael C.
Representing Object Colour in Language Comprehension
ERIC Educational Resources Information Center
Embodied theories of cognition hold that mentally representing something "red" engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task�
Connell, Louise
Prevalence of colour blindness in young Jordanians.
Colour blindness is one of the common genetic disorders observed in all human populations. It is a sex-linked recessive trait. The genes are located on the X chromosome within the Xq28 band. 1,418 university students (1,200 female and 218 male) from Zarka Private University and the Hashemite University were randomly selected and tested for congenital red/green colour blindness, by using Ishihara pseudo-isochromatic colour plates. A total of 23 individuals were found to be colour blind. In females, 4 students (0.33%) were colour blind: 1 of them showed protanomalia, 1 protanopia and 2 deuteranomalia. In males, 19 students (8.72%) were colour blind: 4 showed protanomalia, 3 protanopia, 8 deuteranomalia and 4 deuteranopia. The allelic frequencies of the colour vision gene were found to be 0.087 in males, 0.003 in females and 0.016 in the total population. Studies on colour blindness in Jordan are very few; this population-based investigation is meant to fill a gap in this field. PMID:11125268
Al-Aqtum, M T; Al-Qawasmeh, M H
Colour Mathematics: With Graphs and Numbers
ERIC Educational Resources Information Center
The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just�
LoPresto, Michael C.
Colour changes in bruised apple fruit tissue
A study of changes with time in aspects of bruise colour in �Granny Smith� apples (Malus domestica) was undertaken in an attempt to identify the optimum time for assessment of bruise severity in experiments on apples. Bruised cortical tissue became darker (decreased lightness), browner (decreased hue angle), and increased in colour intensity (increased chroma) in the first few hours following
Waiss Samim; Nigel H. Banks
Modelling Ambient Systems with Coloured Petri Nets.
National Technical Information Service (NTIS)
This paper is concerned with the formal modelling of Ambient Systems, focussing on the issues that emerge in their modelling using coloured Petri nets. A new class of coloured Petri nets, called Ambient Petri Nets (APNs), is introduced. Furthermore, a rel...
A. Konios M. Pietkiewicz-Koutny
Skin colour and bilirubin in neonates
The correlation between the yellow colour of the skin and serum bilirubin concentration, reserve albumin concentration, and pH was investigated in 76 icteric neonates. Significant linear correlation existed between yellow colour of the skin and serum bilirubin concentration, reciprocal of the reserve albumin concentration, and the squared hydrogen ion concentration. Furthermore, the basic yellowness of the skin at birth correlated
A Knudsen; R Brodersen
Skin colour and bilirubin in neonates.
The correlation between the yellow colour of the skin and serum bilirubin concentration, reserve albumin concentration, and pH was investigated in 76 icteric neonates. Significant linear correlation existed between yellow colour of the skin and serum bilirubin concentration, reciprocal of the reserve albumin concentration, and the squared hydrogen ion concentration. Furthermore, the basic yellowness of the skin at birth correlated linearily with the yellow colour of the skin measured when the child became jaundiced. The results support the proposed hypothesis that bilirubin is transferred from plasma to skin through two different mechanisms: (a) leakage of bilirubin-albumin complexes into extravascular spaces and (b) precipitation of bilirubin acid in phospholipid membranes. The latter mechanism suggests that measurement of the yellow colour of the skin may be a better predictor of brain damage than the serum bilirubin concentration and thus be of clinical utility. Measurement of the yellow colour of the skin as a method of obtaining serum bilirubin concentration is unreliable.
Knudsen, A; Brodersen, R
X-ray tomographic imaging of Ti/SiC composites.
In this paper, high-resolution tomographic synchrotron X-ray imaging is applied to study the occurrence and evolution of damage in Ti-6Al-4V/SCS6 SiC fibre composite materials. Three composite morphologies of increasing complexity have been studied, namely single fibre, single-ply and multi-ply composites. The single fibre composite was strained to full fibre fragmentation and the progressive introduction of damage monitored. For the single-ply composite, damage was introduced deliberately by laser drilling to establish the effect of damaged fibres on their neighbours, whereas for the multi-ply composite the morphology of a fibre bridging fatigue crack was studied. In addition to traditional mode I fibre fractures, subsequent fibre wedge cracks were observed presumably nucleating from damage introduced into the fibre surface by the first fracture event. In addition to these crack morphologies, spiral defects were observed for the single ply during failure. Finally, for the multi-ply composite, the matrix crack front showed a number of characteristic features, including advancement in fibre-free regions, crack bifurcation near fibres and different crack plane heights either side of a fibre. PMID:12588527
McDonald, S A; Preuss, M; Maire, E; Buffiere, J-Y; Mummery, P M; Withers, P J
The colour distribution of galaxies at redshift five
NASA Astrophysics Data System (ADS)
We present the results of a study investigating the rest-frame ultraviolet (UV) spectral slopes of redshift z ? 5 Lyman-break galaxies (LBGs). By combining deep Hubble Space Telescope imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and Hubble Ultra-Deep Field with ground-based imaging from the UKIRT Infrared Deep Sky Survey Ultra Deep Survey, we have produced a large sample of z ? 5 LBGs spanning an unprecedented factor of >100 in UV luminosity. Based on this sample we find a clear colour-magnitude relation (CMR) at z ? 5, such that the rest-frame UV slopes (?) of brighter galaxies are notably redder than their fainter counterparts. We determine that the z ? 5 CMR is well described by a linear relationship of the form: d? = (-0.12 � 0.02)dMUV, with no clear evidence for a change in CMR slope at faint magnitudes (i.e. MUV ? -18.9). Using the results of detailed simulations we are able, for the first time, to infer the intrinsic (i.e. free from noise) variation of galaxy colours around the CMR at z ? 5. We find significant (12?) evidence for intrinsic colour variation in the sample as a whole. Our results also demonstrate that the width of the intrinsic UV slope distribution of z ? 5 galaxies increases from ?? ? 0.1 at MUV = -18 to ?? ? 0.4 at MUV = -21. We suggest that the increasing width of the intrinsic galaxy colour distribution and the CMR itself are both plausibly explained by a luminosity-independent lower limit of ? ? -2.1, combined with an increase in the fraction of red galaxies in brighter UV-luminosity bins.
Rogers, A. B.; McLure, R. J.; Dunlop, J. S.; Bowler, R. A. A.; Curtis-Lake, E. F.; Dayal, P.; Faber, S. M.; Ferguson, H. C.; Finkelstein, S. L.; Grogin, N. A.; Hathi, N. P.; Kocevski, D.; Koekemoer, A. M.; Kurczynski, P.
Colour Object recognition combining Motion Descriptors, Zernike Moments and Support Vector Machine
Fourier descriptors have been used successfully in the past to grey-level images, rigid bodied object. Here we used motion descriptors (MD) introduced recently by Gauthier et al., combined with Zernike Moments (ZM), in order to perform a recognition task in colour images. The feature vector for the MD obtained for each object appears to be unique and can be used
Fethi SMACH; C�dric LEMAITRE; Johel MITERAN; Jean Paul GAUTHIER; Mohamed ABID
Front-flash thermal imaging characterization of continuous fiber ceramic composites.
Infrared thermal imaging has become increasingly popular as a nondestructive evaluation method for characterizing materials and detecting defects. One technique, which was utilized in this study, is front-flash thermal imaging. We have developed a thermal imaging system that uses this technique to characterize advanced material systems, including continuous fiber ceramic composite (CFCC) components. In a front-flash test, pulsed heat energy is applied to the surface of a sample, and decay of the surface temperature is then measured by the thermal imaging system. CFCC samples with drilled flat-bottom holes at the back surface (to serve as ''flaws'') were examined. The surface-temperature/time relationship was analyzed to determine the depths of the flaws from the front surface of the CFCC material. Experimental results on carbon/carbon and CFCC samples are presented and discussed.
Deemer, C.
Advanced imaging techniques for assessment of structure, composition and function in biofilm systems.
Scientific imaging represents an important and accepted research tool for the analysis and understanding of complex natural systems. Apart from traditional microscopic techniques such as light and electron microscopy, new advanced techniques have been established including laser scanning microscopy (LSM), magnetic resonance imaging (MRI) and scanning transmission X-ray microscopy (STXM). These new techniques allow in situ analysis of the structure, composition, processes and dynamics of microbial communities. The three techniques open up quantitative analytical imaging possibilities that were, until a few years ago, impossible. The microscopic techniques represent powerful tools for examination of mixed environmental microbial communities usually encountered in the form of aggregates and films. As a consequence, LSM, MRI and STXM are being used in order to study complex microbial biofilm systems. This mini review provides a short outline of the more recent applications with the intention to stimulate new research and imaging approaches in microbiology. PMID:20180852
Neu, Thomas R; Manz, Bertram; Volke, Frank; Dynes, James J; Hitchcock, Adam P; Lawrence, John R
Color composite C-band and L-band image of Kilauea volcanoe on Hawaii
NASA Technical Reports Server (NTRS)
This color composite C-band and L-band image of the Kilauea volcano on the Big Island of Hawaii was acuired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperature Radar (SIR-C/X-SAR) flying on the Space Shuttle Endeavour. The city of Hilo can be seen at the top. The image shows the different types of lava flows around the crater Pu'u O'o. Ash deposits which erupted in 1790 from the summit of Kilauea volcano show up as dark in this image, and fine details associated with lava flows which erupted in 1919 and 1974 can be seen to the south of the summit in an area called the Ka'u Desert. Other historic lava flows can also be seen. Highway 11 is the linear feature running from Hilo to the Kilauea volcano. The Jet Propulsion Laboratory alternative photo number is P-43918.
GrainScan: a low cost, fast method for grain size and colour measurements
Background Measuring grain characteristics is an integral component of cereal breeding and research into genetic control of seed development. Measures such as thousand grain weight are fast, but do not give an indication of variation within a sample. Other methods exist for detailed analysis of grain size, but are generally costly and very low throughput. Grain colour analysis is generally difficult to perform with accuracy, and existing methods are expensive and involved. Results We have developed a software method to measure grain size and colour from images captured with consumer level flatbed scanners, in a robust, standardised way. The accuracy and precision of the method have been demonstrated through screening wheat and Brachypodium distachyon populations for variation in size and colour. Conclusion By using GrainScan, cheap and fast measurement of grain colour and size will enable plant research programs to gain deeper understanding of material, where limited or no information is currently available.
Dielectric Properties of Composite Materials to O(c^2) - Method of Images
NASA Astrophysics Data System (ADS)
The method of images is extended to d-dimensions in order to solve the problem of two hyperspheres in a uniform field E_0. For dielectric inclusions this method entails the study of complex image line dipole and line charge densities. In particular, the O(c^2) coefficient in the low volume fraction expansion of the dielectric constant of a binary composite material, is determined by this method which is in principle exact. We demonstrate explicitly in the singular case of perfect conducting inclusions that our method converges much faster than and is in agreement with the multipole moment expansion method we have studied previously.
Alexopoulos, Aris; Choy, Tuck; Thorpe, M. F.
MERIS-based ocean colour classification with the discrete Forel-Ule scale
NASA Astrophysics Data System (ADS)
Multispectral information from satellite borne ocean colour sensors is at present used to characterize natural waters via the retrieval of concentrations of the three dominant optical constituents; pigments of phytoplankton, non-algal particles and coloured dissolved organic matter. A limitation of this approach is that accurate retrieval of these constituents requires detailed local knowledge of the specific absorption and scattering properties. In addition, the retrieval algorithms generally use only a limited part of the collected spectral information. In this paper we present an additional new algorithm that has the merit of using the full spectral information in the visible domain to characterize natural waters in a simple and globally valid way. This Forel-Ule MERIS (FUME) algorithm converts the normalized multiband reflectance information into a discrete set of numbers using uniform colourimetric functions. The Forel-Ule (FU) scale is a sea colour comparator scale that has been developed to cover all possible natural sea colours, ranging from indigo blue (the open ocean) to brownish-green (coastal water) and even brown (humic-acid dominated) waters. Data using this scale have been collected since the late nineteenth century, and therefore, this algorithm creates the possibility to compare historic ocean colour data with present-day satellite ocean colour observations. The FUME algorithm was tested by transforming a number of MERIS satellite images into Forel-Ule colour index images and comparing in situ observed FU numbers with FU numbers modelled from in situ radiometer measurements. Similar patterns and FU numbers were observed when comparing MERIS ocean colour distribution maps with ground truth Forel-Ule observations. The FU numbers modelled from in situ radiometer measurements showed a good correlation with observed FU numbers (R2 = 0.81 when full spectra are used and R2 = 0.71 when MERIS bands are used).
Wernand, M. R.; Hommersom, A.; van der Woerd, H. J.
BOREAS Level-4c AVHRR-LAC Ten-Day Composite Images: Surface Parameters
NASA Technical Reports Server (NTRS)
The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Satellite Data Acquisition Program focused on providing the research teams with the remotely sensed satellite data products they needed to compare and spatially extend point results. Manitoba Remote Sensing Center (MRSC) and BOREAS Information System (BORIS) personnel acquired, processed, and archived data from the Advanced Very High Resolution Radiometer (AVHRR) instruments on the NOAA-11 and -14 satellites. The AVHRR data were acquired by CCRS and were provided to BORIS for use by BOREAS researchers. These AVHRR level-4c data are gridded, 10-day composites of surface parameters produced from sets of single-day images. Temporally, the 10-day compositing periods begin 11-Apr-1994 and end 10-Sep-1994. Spatially, the data cover the entire BOREAS region. The data are stored in binary image format files. Note: Some of the data files on the BOREAS CD-ROMs have been compressed using the Gzip program.
Cihlar, Josef; Chen, Jing; Huang, Fengting; Nickeson, Jaime; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor)
BOREAS Level-4b AVHRR-LAC Ten-Day Composite Images: At-sensor Radiance
NASA Technical Reports Server (NTRS)
The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Satellite Data Acquisition Program focused on providing the research teams with the remotely sensed satellite data products they needed to compare and spatially extend point results. Manitoba Remote Sensing Center (MRSC) and BOREAS Information System (BORIS) personnel acquired, processed, and archived data from the Advanced Very High Resolution Radiometer (AVHRR) instruments on the National Oceanic and Atmospheric Administration (NOAA-11) and -14 satellites. The AVHRR data were acquired by CCRS and were provided to BORIS for use by BOREAS researchers. These AVHRR level-4b data are gridded, 10-day composites of at-sensor radiance values produced from sets of single-day images. Temporally, the 10- day compositing periods begin 11-Apr-1994 and end 10-Sep-1994. Spatially, the data cover the entire BOREAS region. The data are stored in binary image format files.
Cihlar, Josef; Chen, Jing; Nickerson, Jaime; Newcomer, Jeffrey A.; Huang, Feng-Ting; Hall, Forrest G. (Editor)
Physicochemical and physiological basis of dichromatic colour
NASA Astrophysics Data System (ADS)
Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum.
Kreft, Samo; Kreft, Marko
Measuring the Radiopacity of Flowable Resin Composites Using Scanned Radiograph Images
Radiopacity is a requirement for dental restorative materials that permits evaluation of the integrity and adaptation over time to the restoration of the tooth structure. This work was to investigate amount of fillers and radiopacity of flowable resin composites using scanned radiograph images. Radiographs of samples (8�mm diameter and 1�mm thickness) were taken with a dental X-ray at 60kv, 7�mA,
G. Furtos; B. Baldea; L. Silaghi-Dumitrescu; D. Bratu; M. Moldovan; C. Prejmerean
Automatic Mapping of Surfaces Affected by Forest Fires in Spain Using AVHRR NDVI Composite Image Data
In this work, we describe the statistical techniques used to analyze images from the National Oceanic and Atmo- spheric Administration's' advanced ver~j high resolution radiometer for the calculation and mapping of surfaces affected by large fi)restfires in Spain in 1993 and 1994. Maximum value normalized difference vegetation index (NDVI) composites (MVCs) were generated for every ten-day period over the two
Alberto Ferndndez; Pilar Illera; Jose Luis Casanova
Experimental investigation on capillary force of composite wick structure by IR thermal imaging camera
A novel sintered�grooved composite wick structures has been developed for two-phase heat transfer devices. With ethanol as the working fluid, risen meniscus test is conducted to study the capillary force of wick structures. Infrared (IR) thermal imaging is used to identify and locate the liquid meniscus. The effects of sintered layer, V-grooves and powder size on capillary force are explored.
Yong Tang; Daxiang Deng; Longsheng Lu; Minqiang Pan; Qinghui Wang
Comparison of spread spectrum and pulse signal excitation for split spectrum techniques composite imaging
NASA Astrophysics Data System (ADS)
Ultrasonic imaging of composites was investigated. Glass and carbon fiber reinforced plastic produced by resin transfer molding and prepreg forming were analyzed. In some of the samples air bubbles were trapped during RTM (resin transfer molding) process and interlayer gaps were present in prepreg technology samples. One of the most expected techniques to apply in such case is the Split Spectrum processing. On the other hand such signals require specific processing to reliably reconstruct the temporal position of the defect reflection. Correlation processing can be used for signal compression or Wiener filtering can be applied for spectral content equalisation. Pulse signals are simple to generate, but lack the possibility to alter the signal's spectrum shape. Spread spectrum signals offer a powerful tool for signal energy over frequency band increase and resolution enhancement. CW (continuous wave) burst has high energy but lacks the bandwidth needed for SSP (spread spectrum processing). The aim of the investigation was to compare the performance of the above signals in case of composite imaging, when various Split Spectrum Processing techniques are used with preceding Wiener processing for spectral content compensation. Resulting composite signals and images obtained are presented. Structural noise removal performance was evaluated as Receiver Operating Characteristics (ROC).
Svilainis, L.; Kitov, S.; Rodr�guez, A.; Vergara, L.; Dumbrava, V.; Chaziachmetovas, A.
Biologically motivated composite image sensor for deep-field target tracking
NASA Astrophysics Data System (ADS)
The present work addresses the design of an image acquisition front-end for target detection and tracking within a wide range of distances. Inspired by raptor bird's vision, a novel design for a visual sensor is proposed. The sensor consists of two parts, each originating from the studies of biological vision systems of different species. The front end is comprised of a set of video cameras imitating a falconiform eye, in particular its optics and retina [1]. The back end is a software remapper that uses a popular in machine vision log-polar model of retino-cortical projection in primates [2], [3], [4]. The output of this sensor is a composite log-polar image incorporating both near and far visual fields into a single homogeneous image space. In such space it is easier to perform target detection and tracking for those applications that deal with targets moving along the camera axis. The target object preserves its shape and size being handled seamlessly between cameras regardless of distance to the composite sensor. The prototype of proposed composite sensor has been created and is used as a front-end in experimental mobile vehicle detection and tracking system. Its has been tested inside a driving simulator and results are presented.
Melnyk, Pavlo B.; Messner, Richard A.
Bleeding detection in wireless capsule endoscopy using adaptive colour histogram model and support vector classification
NASA Astrophysics Data System (ADS)
Wireless Capsule Endoscopy (WCE) is a colour imaging technology that enables detailed examination of the interior of the gastrointestinal tract. A typical WCE examination takes ~ 8 hours and captures ~ 40,000 useful images. After the examination, the images are viewed as a video sequence, which generally takes a clinician over an hour to analyse. The manufacturers of the WCE provide certain automatic image analysis functions e.g. Given Imaging offers in their Rapid Reader software: The Suspected Blood Indicator (SBI), which is designed to report the location in the video of areas of active bleeding. However, this tool has been reported to have insufficient specificity and sensitivity. Therefore it does not free the specialist from reviewing the entire footage and was suggested only to be used as a fast screening tool. In this paper we propose a method of bleeding detection that uses in its first stage Hue-Saturation-Intensity colour histograms to track a moving background and bleeding colour distributions over time. Such an approach addresses the problem caused by drastic changes in blood colour distribution that occur when it is altered by gastrointestinal fluids and allow detection of other red lesions, which although are usually "less red" than fresh bleeding, they can still be detected when the difference between their colour distributions and the background is large enough. In the second stage of our method, we analyse all candidate blood frames, by extracting colour (HSI) and texture (LBP) features from the suspicious image regions (obtained in the first stage) and their neighbourhoods and classifying them using Support Vector Classifier into Bleeding, Lesion and Normal classes. We show that our algorithm compares favourably with the SBI on the test set of 84 full length videos.
Mackiewicz, Michal W.; Fisher, Mark; Jamieson, Crawford
Why `false' colours are seen by butterflies
NASA Astrophysics Data System (ADS)
Light can be described by its intensity, spectral distribution and polarization, and normally a visual system analyses these independently to extract the maximum amount of information. Here I present behavioural evidence that this does not happen in butterflies, whose choice of oviposition substrate on the basis of its colour appears to be strongly influenced by the direction of polarization of the light reflected from the substrate. To my knowledge, this is the first record of `false' colours being perceived as a result of light polarization. This detection of false colours may help butterflies to find optimal oviposition sites.
Kelber, Almut
Genetic engineering of novel flower colour by suppression of anthocyanin modification genes in gentian.
Ornamental gentian plants have vivid-blue flowers. The main factor contributing to the flower colour is the accumulation of a polyacylated delphinidin 'gentiodelphin' in their petals. Although in vitro studies proposed that acylation plays an important role in the stability and development of gentian blue colour, the in vivo stability of the polyacylated anthocyanin was not clearly demonstrated. Thus, to reveal the importance of anthocyanin modification, especially acylation, and to engineer new colours of gentian flowers, we used chimeric RNAi technology to produce transgenic gentian plants with downregulated anthocyanin 5,3'-aromatic acyltransferase (5/3'AT) and flavonoid 3',5'-hydroxylase (F3'5'H) activities, which are both essential enzymes for gentiodelphin biosynthesis. Two lines of flower colour-modified plants were obtained from fifteen transgenic gentian plants. Clone no. 1 exhibited a lilac flower colour and clone no. 15 exhibited pale-blue flowers. RNA gel blot analysis confirmed that both transgenic lines had markedly suppressed 5/3'AT transcripts, whereas clone no. 15 had fewer F3'5'H transcripts than clone no. 1 and untransformed control plants. HPLC analysis of anthocyanin compositions showed that downregulation of the 5/3'AT gene led to increased accumulation of non-acylated anthocyanins, as expected. These results demonstrated that genetic engineering to reduce the accumulation of polyacylated anthocyanins could cause modulations of flower colour. PMID:19758726
Nakatsuka, Takashi; Mishiba, Kei-ichiro; Kubota, Akiko; Abe, Yoshiko; Yamamura, Saburo; Nakamura, Noriko; Tanaka, Yoshikazu; Nishihara, Masahiro
Strange Quark Matter and Colour Superconducting Phases of QCD
NASA Astrophysics Data System (ADS)
We discuss the evolution of the bubbles of quark matter which survive from the first-order confinement phase transition till the increase of the internal pressure stops their contraction. We also show that at low temperature and high pressure a quark matter composition u d s is preferred to u d d. We finally describe the different colour superconducting phases which may be formed inside neutron stars, and the topological defects that can be generated, where the stable strangelets might be originated and perhaps already detected at high-altitude observatories.
Masperi, Luis
Sub-surface imaging of carbon nanotube-polymer composites using dynamic AFM methods.
High-resolution sub-surface imaging of carbon nanotube (CNT) networks within polymer nanocomposites is demonstrated through electrical characterization techniques based on dynamic atomic force microscopy (AFM). We compare three techniques implemented in the single-pass configuration: DC-biased amplitude modulated AFM (AM-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) in terms of the physics of sub-surface image formation and experimental robustness. The methods were applied to study the dispersion of sub-surface networks of single-walled nanotubes (SWNTs) in a polyimide (PI) matrix. We conclude that among these methods, the KPFM channel, which measures the capacitance gradient (?C/?d) at the second harmonic of electrical excitation, is the best channel to obtain high-contrast images of the CNT network embedded in the polymer matrix, without the influence of surface conditions. Additionally, we propose an analysis of the ?C/?d images as a tool to characterize the dispersion and connectivity of the CNTs. Through the analysis we demonstrate that these AFM-based sub-surface methods probe sufficiently deep within the SWNT composites, to resolve clustered networks that likely play a role in conductivity percolation. This opens up the possibility of dynamic AFM-based characterization of sub-surface dispersion and connectivity in nanostructured composites, two critical parameters for nanocomposite applications in sensors and energy storage devices. PMID:23478510
Cadena, Maria J; Misiego, Rocio; Smith, Kyle C; Avila, Alba; Pipes, Byron; Reifenberger, Ron; Raman, Arvind
Sub-surface imaging of carbon nanotube-polymer composites using dynamic AFM methods
NASA Astrophysics Data System (ADS)
High-resolution sub-surface imaging of carbon nanotube (CNT) networks within polymer nanocomposites is demonstrated through electrical characterization techniques based on dynamic atomic force microscopy (AFM). We compare three techniques implemented in the single-pass configuration: DC-biased amplitude modulated AFM (AM-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) in terms of the physics of sub-surface image formation and experimental robustness. The methods were applied to study the dispersion of sub-surface networks of single-walled nanotubes (SWNTs) in a polyimide (PI) matrix. We conclude that among these methods, the KPFM channel, which measures the capacitance gradient (?C/?d) at the second harmonic of electrical excitation, is the best channel to obtain high-contrast images of the CNT network embedded in the polymer matrix, without the influence of surface conditions. Additionally, we propose an analysis of the ?C/?d images as a tool to characterize the dispersion and connectivity of the CNTs. Through the analysis we demonstrate that these AFM-based sub-surface methods probe sufficiently deep within the SWNT composites, to resolve clustered networks that likely play a role in conductivity percolation. This opens up the possibility of dynamic AFM-based characterization of sub-surface dispersion and connectivity in nanostructured composites, two critical parameters for nanocomposite applications in sensors and energy storage devices.
Cadena, Maria J.; Misiego, Rocio; Smith, Kyle C.; Avila, Alba; Pipes, Byron; Reifenberger, Ron; Raman, Arvind
Artist's colour rendering of HDR scenes in 3D Mondrian colour-constancy experiments
The presentation provides an update on ongoing research using three-dimensional Colour Mondrians. Two still life arrangements comprising hand-painted coloured blocks of 11 different colours were subjected to two different lighting conditions of a nearly uniform light and directed spotlights. The three-dimensional nature of these test targets adds shadows and multiple reflections, not found in flat Mondrian targets. Working from exactly
Carinna E. Parraman; John J. McCann; Alessandro Rizzi
Across Light: Through Colour II
NASA Astrophysics Data System (ADS)
This paper intends to be a reflection on the end product of the process of preparing movies to digital art holograms, comparing the kind of space and movement between those images and the ones in a previous paper. This paper explores too questions about the act of seeing through those images and it is concerned with the surrounding debate of ideas for new experimental methodologies applied to holographic images.
Azevedo, I.; Richardson, M.; Bernardo, L. M.
Use of discrete chromatic space to tune the image tone in a color image mosaic
NASA Astrophysics Data System (ADS)
Color image process is a very important problem. However, the main approach presently of them is to transfer RGB colour space into another colour space, such as HIS (Hue, Intensity and Saturation). YIQ, LUV and so on. Virutally, it may not be a valid way to process colour airborne image just in one colour space. Because the electromagnetic wave is physically altered in every wave band, while the color image is perceived based on psychology vision. Therefore, it's necessary to propose an approach accord with physical transformation and psychological perception. Then, an analysis on how to use relative colour spaces to process colour airborne photo is discussed and an application on how to tune the image tone in colour airborne image mosaic is introduced. As a practice, a complete approach to perform the mosaic on color airborne images via taking full advantage of relative color spaces is discussed in the application.
Zhang, Zuxun; Li, Zhijiang; Zhang, Jianqing; Zheng, Li
The colour of the human skull.
The colour of the human skull was determined from 124 fresh skull samples using the tristimulus colour measurement system "Micro Color" and listed as The Commission Internationale de l'Eclairage (CIE) L*a*b*-values. The skulls were found to be relatively light (L*=72.5), nearly colourless on the a*-axis (a*=-7.4), and slightly yellow (b*=16.4). No difference was found between the colours of the outer and the inner surfaces of the skulls. Including a small number (n=8) of skulls from diabetic patients in the study, we detected no colour difference between the samples from diabetics and non-diabetics. However, a hitherto unknown correlation between the subjects' age and the yellowness (b*-value) of the skull could be demonstrated. PMID:11230946
Schafer, A T
Angle-Insensitive Structural Colours based on Metallic Nanocavities and Coloured Pixels beyond the Diffraction Limit
To move beyond colorant-based pigmentation display technologies, a variety of photonic and plasmonic crystal based structures have been designed and applied as colour filters. Nanostructure based colour filtering offers increased efficiencies, low power consumption, slim dimensions, and enhanced resolution. However, incident angle tolerance still needs to be improved. In this work, we propose a new scheme through localized resonance in metallic nanoslits by light funneling. Angle insensitive colour filters up to �80 degrees have been achieved, capable of wide colour tunability across the entire visible band with pixel size beyond the diffraction limit (~?/2). This work opens the door to angle insensitive manipulation of light with structural filtering.
Wu, Yi-Kuei Ryan; Hollowell, Andrew E.; Zhang, Cheng; Guo, L. Jay
In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory.
Performance evaluation of local colour invariants
In this paper, we compare local colour descriptors to grey-value descriptors. We adopt the evaluation framework of Mikolayzcyk and Schmid. We modify the framework in several ways. We decompose the evaluation framework to the level of local grey-value invariants on which common region descriptors are based. We compare the discriminative power and invariance of grey-value invariants to that of colour
Gertjan J. Burghouts; Jan-mark Geusebroek
Response of alate aphids to green targets on coloured backgrounds
To study the effect of background colour on aphid landing on green targets (water pan traps), two field experiments were set up in Hessen, Germany, in 2003. Traps were put onto coloured plastic sheets (13 colours, straw mulch, transparent foil, and uncovered soil, Experiment 1). In Experiment 2, green water pans were again put on coloured plastic sheets (red, white,
T. F. Doring; S. M. Kirchner; S. Kuhne; H. Saucke
Inheritance of seed colour in turnip rape ( Brassica campestris L.)
The inheritance of seed colour was investigated in the progenies of crosses between seven yellow seeded forms and a brown seeded one of turnip rape (Brassica campestris L.). Seed colour differences were found to be determined in each case by one or two genes with epistatic effect. Moreover, independent inheritance of hilum colour was observed. Seed colour was predominantly but
A. Schwetka
Mechanisms, functions and ecology of colour vision in the honeybee.
Research in the honeybee has laid the foundations for our understanding of insect colour vision. The trichromatic colour vision of honeybees shares fundamental properties with primate and human colour perception, such as colour constancy, colour opponency, segregation of colour and brightness coding. Laborious efforts to reconstruct the colour vision pathway in the honeybee have provided detailed descriptions of neural connectivity and the properties of photoreceptors and interneurons in the optic lobes of the bee brain. The modelling of colour perception advanced with the establishment of colour discrimination models that were based on experimental data, the Colour-Opponent Coding and Receptor Noise-Limited models, which are important tools for the quantitative assessment of bee colour vision and colour-guided behaviours. Major insights into the visual ecology of bees have been gained combining behavioural experiments and quantitative modelling, and asking how bee vision has influenced the evolution of flower colours and patterns. Recently research has focussed on the discrimination and categorisation of coloured patterns, colourful scenes and various other groupings of coloured stimuli, highlighting the bees' behavioural flexibility. The identification of perceptual mechanisms remains of fundamental importance for the interpretation of their learning strategies and performance in diverse experimental tasks. PMID:24828676
Hempel de Ibarra, N; Vorobyev, M; Menzel, R
Colourful parrot feathers resist bacterial degradation
The brilliant red, orange and yellow colours of parrot feathers are the product of psittacofulvins, which are synthetic pigments known only from parrots. Recent evidence suggests that some pigments in bird feathers function not just as colour generators, but also preserve plumage integrity by increasing the resistance of feather keratin to bacterial degradation. We exposed a variety of colourful parrot feathers to feather-degrading Bacillus licheniformis and found that feathers with red psittacofulvins degraded at about the same rate as those with melanin and more slowly than white feathers, which lack pigments. Blue feathers, in which colour is based on the microstructural arrangement of keratin, air and melanin granules, and green feathers, which combine structural blue with yellow psittacofulvins, degraded at a rate similar to that of red and black feathers. These differences in resistance to bacterial degradation of differently coloured feathers suggest that colour patterns within the Psittaciformes may have evolved to resist bacterial degradation, in addition to their role in communication and camouflage.
Burtt, Edward H.; Schroeder, Max R.; Smith, Lauren A.; Sroka, Jenna E.; McGraw, Kevin J.
Seasonal colour and antipredator behaviour in Etheostoma (Percidae).
This study examined how colour varies across season and sex in the fantail darter Etheostoma flabellare and the banded darter Etheostoma zonale. Etheostoma flabellare has male-only parental care and exhibited slight sexual dimorphism in overall colour, with no discernible effect of season on colour; whereas E. zonale does not have parental care and exhibited substantial sexual dimorphism in colour, but only in the breeding season. Additionally, antipredator behaviour of E. zonale was compared between males that were fully coloured during the breeding season and males that were partially coloured at that time, but the effects of colour and season were not consistent across males. PMID:24588710
Moran, R L; von Ende, C N; King, B H
Applying an 8-bit multispectral color-composite image simulation technique to operational real-time AVHRR data
NASA Technical Reports Server (NTRS)
The Geophysics Directorate's 8-bit multispectral color-composite image display technique has been installed on the Satellite Data Processing System at the German Military Geophysical Office in Traben-Trarbach, Germany. The technique simulates 24-bit full-color composites on 8-bit color workstations, combining image data from the NOAA multispectral Advanced Very High Resolution Radiometer. The real-time application of this technique to operational satellite data is discussed.
Klaes, K. D.; D'Entremont, Robert P.; Thomason, Larry W.
Follicular contact dermatitis due to coloured permanent-pressed sheets
A delayed hypersensitivity type of allergic contact dermatitis was observed following exposure to certain brands of 50% cotton, 50% polyester coloured permanent-pressed sheets produced by a particular manufacturer. The dermatitis presented as an extremely pruritic follicular eczema of the body and vesicular edema of the ears and face. Patch testing excluded formalin as the allergen but suggested permanent-pressing chemicals as a possibility. Several washings of the sheets did not prevent the development of the dermatitis. The removal of sheets did not immediately result in improvement: the condition could persist for up to eight weeks after their discontinuance. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5
Panaccio, Francois; Montgomery, D. C.; Adam, J. E.
Changes in CIELab colour parameters due to extrusion of rice-greengram blend: a response surface approach
Rice-greengram blend was extruded using a co-rotating twin-screw extruder. A central composite rotatable experimental design was employed to determine the effect of barrel temperature and screw speed on the colour of the extrudates using the CIE Lab system of measurement. The colour parameters (L?, a? and b? values) were related (r? 0.876, P ? 0.01) to the extrusion variables by
Suvendu Bhattacharya; V. Sivakumar; Devopriyo Chakraborty
Mercury `s composition studied by the Visible and Infrared Hyperspectral Imager (VIHI) of the Bepi colombo MPO Mission
We describe the contributions that we expect by the Visual and Infrared Hyper-spectral Imager channel (VIHI) to make towards increased knowledge and understanding of Mercury's surface and composition. Due to the difficulties of observing Mercury from ground, relatively little is known about its surface composition, and Mercury spectra are vulnerable to incomplete removal of telluric absorptions. VIHI will provide valuable
Maria Cristina de Sanctis; Fabrizio Capaccioni; Gianrico Filacchione; Eleonora Ammannito; Alain Doressoundiram; Stephane Erard; Maria Sgavetti
Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging
NASA Astrophysics Data System (ADS)
Ceramic matrix composites are being developed for numerous high temperature applications, including rotors and combustors for advanced turbine engines, heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon-carbide-fiber- reinforced-silicon-carbide (SiC(f)/SiC), silicon-carbide-fiber-reinforced-silicon-nitride (SiC(f)/Si3N4), aluminum-oxide-reinforced-alumina (Al2O3(f)/Al2O3, etc. In the manufacturing of these ceramic composites, the conditions of the fiber/matrix interface are critical to the mechanical and thermal behavior of the component. Defects such as delaminations and non-uniform porosity can directly affect the performance. A nondestructive evaluation (NDE) method, developed at Argonne National Laboratory has proved beneficial in analyzing as-processed conditions and defect detection created during manufacturing. This NDE method uses infrared thermal imaging for full-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Nonuniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares-estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fiber coating in a full array of test specimens.
Ahuja, Sanjay; Ellingson, William A.; Stuckey, J.; Koehl, E. R.
Arnheim's Gestalt theory of visual balance: Examining the compositional structure of art photographs and abstract images
In Art and Visual Perception, Rudolf Arnheim, following on from Denman Ross's A Theory of Pure Design, proposed a Gestalt theory of visual composition. The current paper assesses a physicalist interpretation of Arnheim's theory, calculating an image's centre of mass (CoM). Three types of data are used: a large, representative collection of art photographs of recognised quality; croppings by experts and non-experts of photographs; and Ross and Arnheim's procedure of placing a frame around objects such as Arnheim's two black disks. Compared with control images, the CoM of art photographs was closer to an axis (horizontal, vertical, or diagonal), as was the case for photographic croppings. However, stronger, within-image, paired comparison studies, comparing art photographs with the CoM moved on or off an axis (the �gamma-ramp study�), or comparing adjacent croppings on or off an axis (the �spider-web study�), showed no support for the Arnheim�Ross theory. Finally, studies moving a frame around two disks, of different size, greyness, or background, did not support Arnheim's Gestalt theory. Although the detailed results did not support the Arnheim�Ross theory, several significant results were found which clearly require explanation by any adequate theory of the aesthetics of visual composition.
McManus, I C; Stover, Katharina; Kim, Do
A brief discussion about image quality and SEM methods for quantitative fractography of polymer composites.
The methodology for fracture analysis of polymeric composites with scanning electron microscopes (SEM) is still under discussion. Many authors prefer to use sputter coating with a conductive material instead of applying low-voltage (LV) or variable-pressure (VP) methods, which preserves the original surfaces. The present work examines the effects of sputter coating with 25 nm of gold on the topography of carbon-epoxy composites fracture surfaces, using an atomic force microscope. Also, the influence of SEM imaging parameters on fractal measurements is evaluated for the VP-SEM and LV-SEM methods. It was observed that topographic measurements were not significantly affected by the gold coating at tested scale. Moreover, changes on SEM setup leads to nonlinear outcome on texture parameters, such as fractal dimension and entropy values. For VP-SEM or LV-SEM, fractal dimension and entropy values did not present any evident relation with image quality parameters, but the resolution must be optimized with imaging setup, accompanied by charge neutralization. PMID:22915360
Hein, L R O; Campos, K A; Caltabiano, P C R O; Kostov, K G
High resolution VIMS images of Titan's surface: implications for its composition, internal structure and dynamics
NASA Astrophysics Data System (ADS)
With a field of view of 0.5 mrad per pixel, the VIMS (Visual and Infrared Mapping Spectrometer) onboard the Cassini spacecraft can acquire images with a resolution of 500 m per pixel at closest approach during a typical Titan flyby. This resolution is comparable to the resolution of the radar instrument and allows comparisons between the radar images and optical images in the six infrared windows where the surface can be observed. Such opportunities were not set up for the nominal tour before Saturn insertion. The opportunity was offered during the TA flyby [Sotin et al., Nature, 2005] and the results lead the Cassini program to give VIMS the prime observations during closest approach at the T24 and T38 flybys. Two different implementations were experienced. During the T24 flyby (01/29/2007), we used a push-broom mode allowing VIMS to image a long path before pointing to a specific site at the limit between the light and dark terrains. This observation allowed us to see the dunes and to infer some information on their composition [Barnes et al., Icarus, 2008], to image channels and to infer information of erosion processes of the bright equatorial regions [Jaumann et al., Icarus, in press] and to observe the strong correlation between radar images and the VIMS images over a bright area interpreted as a flow feature [Lopes et al., Icarus, 2007]. During the T38 flyby over Ontario Lacus (12/05/2007), it was decided to point to the lake and get different images which provide us with a set of observations obtained with different emergence angles. This observation allowed us to infer the liquid nature of the lake and the composition of the lake [Brown et al., Nature, 2008]. In addition, this mode gives good information on the atmospheric component and will help us remove that component to get better spectra of Titan's surface. During the extended mission, two observations are forecasted at the beginning and at the end of the Cassini Equinox Mission. The first one will happen on November 19, 2008. The VIMS has been programmed to observe the Huygens landing site area at a resolution of 1 km/pixel. Before and after this observation, the push-broom mode will be used in order to cross-cut some of the radar paths. Because Titan's spin rate may be different from synchronous [Stiles et al., 2007; Lorenz et al., 2008], there is some uncertainty on the pointing. This study will report on the results of this flyby. This work has been carried out at the JPL, Caltech, under contract with NASA.
Sotin, C.; Le Mouelic, S.; Le Corre, L.; Barnes, J.; Brown, R. H.; Jaumann, R.; Buratti, B.; Baines, K.; Clark, R.; Nicholson, P.; Soderblom, L.
Modeling dental composite shrinkage by digital image correlation and finite element methods
NASA Astrophysics Data System (ADS)
Dental composites are light-curable resin-based materials with an inherent defect of polymerization shrinkage which may cause tooth deflection and debonding of restorations. This study aimed to combine digital image correlation (DIC) and finite element analysis (FEA) to model the shrinkage behaviors under different light curing regimens. Extracted human molars were prepared with proximal cavities for composite restorations, and then divided into three groups to receive different light curing protocols: regular intensity, low intensity, and step-curing consisting of low and high intensities. For each tooth, the composite fillings were consecutively placed under both unbonded and bonded conditions. At first, the shrinkage of the unbonded restorations was analyzed by DIC and adopted as the setting of FEA. The simulated shrinkage behaviors obtained from FEA were further validated by the measurements in the bonded cases. The results showed that different light curing regimens affected the shrinkage in unbonded restorations, with regular intensity showing the greatest shrinkage strain on the top surface. The shrinkage centers in the bonded cases were located closer to the cavity floor than those in the unbonded cases, and were less affected by curing regimens. The FEA results showed that the stress was modulated by the accumulated light energy density, while step-curing may alleviate the tensile stress along the cavity walls. In this study, DIC provides a complete description of the polymerization shrinkage behaviors of dental composites, which may facilitate the stress analysis in the numerical investigation.
Chen, Terry Yuan-Fang; Huang, Pin-Sheng; Chuang, Shu-Fen
NSDL National Science Digital Library
In this activity, learners explore how composites work by creating and testing their own composite for an imaginary company. This activity shows learners that composites are simply materials that are made up of two or more visibly distinct substances. Use this activity to talk about how composites are everywhere in our lives.
Research, Cornell C.
Colour within an internalist framework: The role of 'colour' in the structure of the perceptual system
Colour is, according to prevailing orthodoxy in perceptual psychology, a kind of autonomous and unitary attribute. It is regarded as unitary or homogeneous by assuming that its core properties do not depend on the type of 'perceptual object' to which it pertains and that 'colour per se' constitutes a natural attribute in the functional architecture of the perceptual system. It
Rainer Mausfeld
Memory colours and colour quality evaluation of conventional and solid-state lamps.
A colour quality metric based on memory colours is presented. The basic idea is simple. The colour quality of a test source is evaluated as the degree of similarity between the colour appearance of a set of familiar objects and their memory colours. The closer the match, the better the colour quality. This similarity was quantified using a set of similarity distributions obtained by Smet et al. in a previous study. The metric was validated by calculating the Pearson and Spearman correlation coefficients between the metric predictions and the visual appreciation results obtained in a validation experiment conducted by the authors as well those obtained in two independent studies. The metric was found to correlate well with the visual appreciation of the lighting quality of the sources used in the three experiments. Its performance was also compared with that of the CIE colour rendering index and the NIST colour quality scale. For all three experiments, the metric was found to be significantly better at predicting the correct visual rank order of the light sources (p < 0.1). PMID:21164972
Smet, Kevin A G; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter
Visual ecology of flies with particular reference to colour vision and colour preferences.
The visual ecology of flies is outstanding among insects due to a combination of specific attributes. Flies' compound eyes possess an open rhabdom and thus separate rhabdomeres in each ommatidium assigned to two visual pathways. The highly sensitive, monovariant neural superposition system is based on the excitation of the peripheral rhabdomeres of the retinula cells R1-6 and controls optomotor reactions. The two forms of central rhabdomeres of R7/8 retinula cells in each ommatidium build up a system with four photoreceptors sensitive in different wavelength ranges and thought to account for colour vision. Evidence from wavelength discrimination tests suggests that all colour stimuli are assigned to one of just four colour categories, but cooperation of the two pathways is also evident. Flies use colour cues for various behavioural reactions such as flower visitation, proboscis extension, host finding, and egg deposition. Direct evidence for colour vision, the ability to discriminate colours according to spectral shape but independent of intensity, has been demonstrated for few fly species only. Indirect evidence for colour vision provided from electrophysiological recordings of the spectral sensitivity of photoreceptors and opsin genes indicates similar requisites in various flies; the flies' responses to coloured targets, however, are much more diverse. PMID:24664124
Lunau, Klaus
Nanoscale Imaging of Mineral Crystals inside Biological Composite Materials Using X-Ray Diffraction Microscopy
NASA Astrophysics Data System (ADS)
We for the first time applied x-ray diffraction microscopy to the imaging of mineral crystals inside biological composite materials�intramuscular fish bone�at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization. Based on the experimental results and biomineralization analyses, we suggested a dynamic model to account for the nucleation and growth of mineral crystals in the collagen matrix. The results obtained from this study not only further our understanding of the complex structure of bone, but also demonstrate that x-ray diffraction microscopy will become an important tool to study biological materials.
Jiang, Huaidong; Ramunno-Johnson, Damien; Song, Changyong; Amirbekian, Bagrat; Kohmura, Yoshiki; Nishino, Yoshinori; Takahashi, Yukio; Ishikawa, Tetsuya; Miao, Jianwei
Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests
NASA Technical Reports Server (NTRS)
Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.
Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.
Drug delivery/imaging multifunctionality of mesoporous silica-based composite nanostructures.
Introduction: Biocompatible mesoporous silica nanoparticles (MSNs) are regarded as one of the most promising inorganic drug delivery systems (DDSs) to concurrently enhance the therapeutic efficiency and mitigate the side effects of anticancer drugs. Elaborately combining multicomponents with MSNs will endow them with specific functionalities for cancer therapy and diagnosis, such as targeted drug delivery, intelligent on-demand drug releasing, synergistic therapy, diagnostic imaging and so on. Areas covered: This review discusses the state-of-the-art potential obstacles and further perspectives of the chemical design/synthesis, in vitro/in vivo pharmaceutical evaluations and potential clinical translations of multifunctional mesoporous silica-based nanomaterials for biotechnological and biomedical applications, especially against cancer. These topics cover the years from 2001 to 2013. Expert opinion: Through the comprehensive evaluations of the biosafety and pharmaceutical efficiency, elaborately designed/fabricated mesoporous silica-based composite nanoparticles show great potentials in clinical applications for efficient diagnostic imaging and chemotherapy of cancer. PMID:24746014
Chen, Yu; Chen, Hangrong; Shi, Jianlin
Colour unmasks dark targets in complex displays.
Recent studies have suggested that colour (meaning chromatic) variations help the visual system segment luminance-variegated displays into their illumination and reflectance layers. This leads to the prediction that colour variations should unmask partially camouflaged achromatic transparencies on luminance-variegated backgrounds. We used 'Mondrian-like' backgrounds that were either achromatic, i.e., varying only in luminance, or chromatic, which in our stimuli meant varying in both luminance and colour. Both achromatic and chromatic backgrounds had the same luminance distribution. Thresholds for detecting simulated transparency targets were found to be lower when on the chromatic compared to achromatic backgrounds. We hypothesised that the chromatic-background advantage resulted from the extra cue provided by colour as to which borders were background and which transparency, predicting that (a) randomising the colours on either side of the transparency border, (b) rotating the target to destroy its X-junctions, and (c) viewing the target eccentrically, would each destroy the chromatic-background advantage. However, none of these predictions was upheld. We suggest therefore that the chromatic-background advantage is due to a low-level, rather than border-disambiguation mechanism. We suggest that chromatic variations reduce the noise, but not the signal, in the mechanism that detects dark targets in complex displays. PMID:16226784
Kingdom, Frederick A A; Kasrai, Reza
Pixel based skin colour classification exploiting explicit skin cluster definition methods
In this paper we examine the performance, on a large and heterogeneous image database, of various skin detectors based on explicit colour skin cluster definition, coupled with a cast remover to see whether, and to what degree, the effectiveness of classification is improved, regardless of the strategy adopted. We also evaluate the hypothesis that a combination of some of the
F. Gasparini; S. Corchs; R. Schettini
Variability in Avian Eggshell Colour: A Comparative Study of Museum Eggshells
Background The exceptional diversity of coloration found in avian eggshells has long fascinated biologists and inspired a broad range of adaptive hypotheses to explain its evolution. Three main impediments to understanding the variability of eggshell appearance are: (1) the reliable quantification of the variation in eggshell colours; (2) its perception by birds themselves, and (3) its relation to avian phylogeny. Here we use an extensive museum collection to address these problems directly, and to test how diversity in eggshell coloration is distributed among different phylogenetic levels of the class Aves. Methodology and Results Spectrophotometric data on eggshell coloration were collected from a taxonomically representative sample of 251 bird species to determine the change in reflectance across different wavelengths and the taxonomic level where the variation resides. As many hypotheses for the evolution of eggshell coloration assume that egg colours provide a communication signal for an avian receiver, we also modelled reflectance spectra of shell coloration for the avian visual system. We found that a majority of species have eggs with similar background colour (long wavelengths) but that striking differences are just as likely to occur between congeners as between members of different families. The region of greatest variability in eggshell colour among closely related species coincided with the medium-wavelength sensitive region around 500 nm. Conclusions The majority of bird species share similar background eggshell colours, while the greatest variability among species aligns with differences along a red-brown to blue axis that most likely corresponds with variation in the presence and concentration of two tetrapyrrole pigments responsible for eggshell coloration. Additionally, our results confirm previous findings of temporal changes in museum collections, and this will be of particular concern for studies testing intraspecific hypotheses relating temporal patterns to adaptation of eggshell colour. We suggest that future studies investigating the phylogenetic association between the composition and concentration of eggshell pigments, and between the evolutionary drivers and functional impacts of eggshell colour variability will be most rewarding.
Cassey, Phillip; Portugal, Steven J.; Maurer, Golo; Ewen, John G.; Boulton, Rebecca L.; Hauber, Mark E.; Blackburn, Tim M.
Characterization of distensibility, plaque burden, and composition of the atherosclerotic carotid artery using magnetic resonance imaging
Purpose: Arterial distensibility is a marker that can measure vessel wall functional and structural changes resulting from atherosclerosis with applications including estimation of mechanical properties of the wall. We sought to assess the feasibility of using magnetic resonance imaging (MRI) to include wall distensibility in the characterization of atherosclerotic carotid arteries and to analyze the relationship between distensibility and morphological and compositional plaque features. Methods: Five healthy volunteers were imaged with a multiple-slice CINE MR sequence twice, within 24 h, to determine the interscan reproducibility of distensibility measurements. Twenty-one subjects with >15% carotid stenosis and the five healthy volunteers were imaged using a multicontrast carotid MRI protocol to characterize arterial wall morphology and composition. Normalized wall index (wall area/total vessel area), maximum wall thickness and, if present, percentages of wall area occupied by calcification and lipid-rich necrotic core were determined. A multiple-slice CINE MR sequence was added to the multicontrast protocol to measure the distensibility coefficient (DC) at several locations spanning the bifurcation. The intraclass correlation coefficient (ICC) and the coefficient of variation were used to assess the reproducibility of DC measurements made on the healthy subjects. The DC was compared between arterial segments and between the healthy and diseased groups. Furthermore, within the diseased group, DC was correlated to plaque morphology and composition at each location as well as that averaged over the plaque. Results: Distensibility measurements were highly reproducible: ICC (95% confidence interval) was 0.998 (0.96�1.0) for the common carotid segment and 0.990 (0.92�1.0) for the internal carotid segment. In healthy volunteers, we found significantly higher distensibility in the common segment of the carotid artery compared to the internal carotid segment (mean � SD = 4.56 � 1.02 versus 3.56 � 1.32 � 10?5/Pa; p < 0.05). However, no segmental differences were seen in the diseased group (3.25 � 1.84 versus 3.26 � 1.60 � 10?5/Pa; p = 0.607). Location-to-location changes in DC were not found to correlate to changes in the local plaque morphology or composition nor were average DC found to be associated with aggregate plaque features. Conclusions: These results demonstrate the feasibility of MRI to measure distensibility in the carotid artery and to presumably detect changes in distensibility due to age and/or disease. The results suggest that the effect of atherosclerosis on local distensibility may not strongly depend upon the specific underlying plaque features in mild to moderate stenotic carotid lesions though more diffuse or nonlocal changes in arterial distensibility could not be ruled out.
Canton, Gador; Hippe, Daniel S.; Sun, Jie; Underhill, Hunter R.; Kerwin, William S.; Tang, Dalin; Yuan, Chun
Magnetite/CdTe magnetic-fluorescent composite nanosystem for magnetic separation and bio-imaging
NASA Astrophysics Data System (ADS)
A new synthesis protocol is described to obtain a CdTe decorated magnetite bifunctional nanosystem via dodecylamine (DDA) as cross linker. High resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray spectroscopy (EDAX), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and fluorescence microscopy are used to characterize the constitution, size, composition and physical properties of these superparamagnetic-fluorescent nanoparticles. These CdTe decorated magnetite nanoparticles were then functionalized with anti-epidermal growth factor receptor (EGFR) antibody to specifically target cells expressing this receptor. The EGFR is a transmembrane glycoprotein and is expressed on tumor cells from different tissue origins including human leukemic cell line Molt-4 cells. The magnetite-CdTe composite nanosystem is shown to perform excellently for specific selection, magnetic separation and fluorescent detection of EGFR positive Molt-4 cells from a mixed population. Flow cytometry and confocal laser scanning microscopy results show that this composite nanosystem has great potential in antibody functionalized magnetic separation and imaging of cells using cell surface receptor antibody.
Kale, Anup; Kale, Sonia; Yadav, Prasad; Gholap, Haribhau; Pasricha, Renu; Jog, J. P.; Lefez, Benoit; Hannoyer, B�atrice; Shastry, Padma; Ogale, Satishchandra
Highly-spatial resolved surface structure and composition by LEEM image intensity analysis
NASA Astrophysics Data System (ADS)
Controlling the local structure and composition of a surface alloy is of great importance in thin film technologies. However, measuring the alloy's heterogeneity is very difficult, because existing experimental techniques either assume lateral homogeneity or have limited subsurface or chemical sensitivity. In this work we have analyzed the electron diffraction intensity vs. incident energy curves of the (00) beam acquired from low-energy electron microscopy (LEEM) images. In contrast to conventional LEED-IV we are able to extract structural and local composition in the surface region with a lateral resolution of 8 nm. Two challenges in applying multiple electron scattering calculations to the analysis of LEEM data are the low and limited electron energy range (10 to 100 eV), which we address by a careful choice of the energy-dependent real and imaginary part of the optical potential. Our analysis of the LEEM IV curves for the clean Cu(001) and Pd/Cu(001) surfaces gives excellent agreement between experimental and best-fit data and good agreement with previous structural investigations. Our new analysis technique is capable of determining surface structure and composition with high accuracy.
Sun, J.; Hannon, J. B.; Kellogg, G. L.; Pohl, K.
Reversals of the colour-depth illusion explained by ocular chromatic aberration.
Although many colour-depth phenomena are predictable from the interocular difference in monocular chromatic diplopia caused by the eye's transverse chromatic aberration (TCA), several reports in the literature suggest that other factors may also be involved. To test the adequacy of the optical model under a variety of conditions, we have determined experimentally the effects of background colour on perceived monocular chromatic diplopia and perceived depth (chromostereopsis). A Macintosh colour monitor was used to present red, blue, and green test stimuli which were viewed monocularly or binocularly (haploscopically) through 1.78 mm artificial pupils. These apertures were displaced nasally and temporally from the visual axis under controlled conditions to induce a variable degree of TCA. Monocular chromatic diplopia and binocular chromostereopsis were measured for red and blue targets, and also for red and green targets, presented on either a black background or on a background which was composed of the sum of the targets' spectral composition (e.g. red and blue presented on magenta; red and green presented on yellow). In all cases, chromatic diplopia and chromostereopsis were found experimentally to reverse in sign with this change in background. Furthermore, we found that a given coloured target could be located in different depth planes within the same display when located on different background colours. These seemingly paradoxical results could nevertheless be explained by a simple model of optical TCA without the need to postulate additional factors or mechanisms. PMID:7483309
Winn, B; Bradley, A; Strang, N C; McGraw, P V; Thibos, L N
Correlative nanoscale 3D imaging of structure and composition in extended objects.
Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D) resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies. PMID:23185554
Xu, Feng; Helfen, Lukas; Suhonen, Heikki; Elgrabli, Dan; Bayat, Sam; Reischig, P�ter; Baumbach, Tilo; Cloetens, Peter
Correlative Nanoscale 3D Imaging of Structure and Composition in Extended Objects
Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D) resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies.
Xu, Feng; Helfen, Lukas; Suhonen, Heikki; Elgrabli, Dan; Bayat, Sam; Reischig, Peter; Baumbach, Tilo; Cloetens, Peter
Effects of different repolishing techniques on colour change of provisional prosthetic materials.
OBJECTIVES. To investigate repolishing effect of stained provisional prosthetic materials in vitro. METHODS. Thirty two cylindrical specimens (10 x 2 mm) were prepared for each of light-polymerized composites (Revotek LC, Rx-Create), bis-acryl composites (Structur Premium, Protemp Garant3, Luxatemp Fluorescence), methyl-methacrylate (UnifastTRAD) and ethyl-methacrylate (DentalonPlus) based provisional material using a mould. The specimens were divided into 4 groups (n=8) according to different repolishing techniques. The specimens were stored for 24 hours at 37 degrees C in distilled water, and then transferred into 4 different staining agents. The colour was measured with a spectrophotometer (Vita Easyshade) before exposure and after repolishing procedures, and colour changes (DeltaE) were calculated. Statistical analysis: three-way ANOVA, Tukey HSD post-hoc test (p<0.05). RESULTS. The influence of type of provisional material, polishing procedure, food colorants and combinations of them on colour change was significant (p<0.05). After the repolishing procedures, all the specimens stored in distilled water achieved an unnoticeable colour change (DeltaE<3.7), except Dentalon Plus, Rx Create, Unifast TRAD. A similar tendency was observed in artificial food colourant solution following subsequent repolishing of the specimens. As for the red wine, all repolished specimens attained unnoticeable colour change (DeltaE<3.7), except Dentalon Plus using Rx polishing paste, Enhance polishing set or repeated glazing procedure. CONCLUSION. Repolishing was found to be an effective way to improve aesthetic appearance for provisional prosthetic materials by partially removing staining observed on the surface of the restorations. PMID:20179397
Rutkunas, Vygandas; Sabaliauskas, Vaidotas
Symphony of colours in the Tarantula
NASA Astrophysics Data System (ADS)
hi-res Size hi-res: 1058 Kb Credits: ESA/NASA, ESO and Danny LaCrue Symphony of colours in the Tarantula The Tarantula is situated 170 000 light-years away in the Large Magellanic Cloud (LMC) in the southern sky and is clearly visible to the naked eye as a large milky patch. Astronomers believe that this smallish irregular galaxy is currently going through a violent period in its life. It is orbiting around the Milky Way and has had several close encounters with it. It is believed that the interaction with the Milky Way has caused an episode of energetic star formation - part of which is visible as the Tarantula Nebula. Just above the centre of the image there is a huge cluster of very hot stars called R136. The stars in R136 are also among the most massive stars we know. R136 is also a very young cluster, its oldest stars being 'just' 5 million years old or so. Its smallest stars, however, are still forming, so astronomers observe R136 to try to understand the early stages of stellar evolution. Near the lower edge of the image we find the star cluster Hodge 301. Hodge 301 is almost 10 times older than R136. Some of the stars in Hodge 301 are so old that they have already exploded as supernovae. The shockwave from this explosion has compressed the gas in the Tarantula into the filaments and sheets that are seen around the cluster. This mosaic of the Tarantula Nebula consists of images from the NASA/ESA Hubble Space Telescope�s Wide Field and Planetary Camera 2 (WFPC2) and was created by 23 year old amateur astronomer Danny LaCrue. The image was constructed by 15 individual exposures taken through three narrow-band filters allowing light from ionised oxygen (501 nm, shown as blue), hydrogen-alpha (656 nm, shown as green) and ionised sulphur (672 nm, shown as red). The exposure time for the individual WFPC2 images vary between 800 and 2800 seconds in each filter. The Hubble data have been superimposed onto images taken through matching narrow-band filters with the European Southern Observatory�s New Technology Telescope at the La Silla Observatory, Chile. The Tarantula Nebula, also known as 30 Doradus, is situated 170 000 light-years away in the Large Magellanic Cloud (LMC) in the southern sky and is clearly visible to the naked eye as a large milky patch. Astronomers believe that this smallish, irregular galaxy is currently going through a violent period in its life cycle. It is orbiting the Milky Way and has had several close encounters with it. It is believed that the interaction with the Milky Way has caused an episode of energetic star formation - part of which is visible as the Tarantula Nebula. The Tarantula is the largest stellar nursery we know in the local universe. In fact if this enormous complex of stars, gas and dust were at the distance of the Orion Nebula it would be visible during the day and cover a quarter of the sky. Over the years the NASA/ESA Hubble Space Telescope has returned again and again to observe this interesting region of the sky and in this way Hubble has built up an archival treasure of more than a thousand images and spectra of the Tarantula. A few weeks ago, 23 year old amateur astronomer Danny LaCrue sifted through the data and found that 15 of the exposures made with Hubble�s Wide Field and Planetary Camera 2 could be combined to create a beautiful mosaic of the central parts of the unique Tarantula. Danny submitted his image to the Hubble European Space Agency Information Centre in the hope that the image could be shared with a wider audience. �I always wondered what it would be like to create the pictures from Hubble, but I never imagined that I would one day actually get to make one myself�. Driven by his interest in astronomy and graphical design and excited at the prospect of processing real images taken by Hubble, Danny recently downloaded the ESA/ESO/NASA Photoshop FITS Liberator from the Spacetelescope.org website. The FITS Liberator is a software tool released six months ago that enables laypeople to work with the somewhat special format of astronomical images (called
Photographing the synergy between magnetic and colour properties in spin crossover material [Fe(NH2trz)3](BF4)2: a temperature sensor perspective.
We introduce the first method for imaging colour changes related to a spin crossover phenomenon induced by thermal variation which can be determined with the naked eye or with a photographic digital camera in a solid phase sensor. PMID:23183554
Lapresta-Fern�ndez, Alejandro; Titos-Padilla, Silvia; Herrera, Juan Manuel; Salinas-Castillo, Alfonso; Colacio, Enrique; Capit�n Vallvey, Luis Ferm�n
Floral colour versus phylogeny in structuring subalpine flowering communities
The relative number of seeds produced by competing species can influence the community structure; yet, traits that influence seed production, such as pollinator attraction and floral colour, have received little attention in community ecology. Here, we analyse floral colour using reflectance spectra that include near-UV and examined the phylogenetic signal of floral colour. We found that coflowering species within communities tended to be more divergent in floral colour than expected by chance. However, coflowering species were not phylogenetically dispersed, in part due to our finding that floral colour is a labile trait with a weak phylogenetic signal. Furthermore, while we found that locally rare and common species exhibited equivalent floral colour distances from their coflowering neighbours, frequent species (those found in more communities) exhibited higher colour distances from their coflowering neighbours. Our findings support recent studies, which have found that (i) plant lineages exhibit frequent floral colour transitions; and (ii) traits that influence local population dynamics contribute to community structure.
McEwen, Jamie R.; Vamosi, Jana C.
Quantum entanglement of quark colour states
An analysis of quantum entanglement between the states of static colour charges in the vacuum of pure Yang-Mills theory is carried out. Hilbert space of physical states of the fields and the charges is endowed with a direct product structure by attaching an infinite Dirac string to each charge.
Buividovich, P. V. [JIPNR, National Academy of Science, 220109 Belarus, Minsk, Acad. Krasin str. 99 (Belarus); ITEP, 117218 Russia, Moscow, B. Cheremushkinskaya str. 25 (Russian Federation); Kuvshinov, V. I. [JIPNR, National Academy of Science, 220109 Belarus, Minsk, Acad. Krasin str. 99 (Belarus)
Fast Synthesis of Dynamic Colour Textures
Textural appearance of many real word materials is not static but shows progress in time. If such a progress is spa- tially and temporally homogeneous these materials can be represented by means of dynamic texture (DT). DT mod- elling is a challenging problem which can add new quality into computer graphics applications. We propose a novel hybrid method for colour
Jir� Filip; Michal Haindl; Dmitry Chetverikov
Genetics of human iris colour and patterns.
The presence of melanin pigment within the iris is responsible for the visual impression of human eye colouration with complex patterns also evident in this tissue, including Fuchs' crypts, nevi, Wolfflin nodules and contraction furrows. The genetic basis underlying the determination and inheritance of these traits has been the subject of debate and research from the very beginning of quantitative trait studies in humans. Although segregation of blue-brown eye colour has been described using a simple Mendelian dominant-recessive gene model this is too simplistic, and a new molecular genetic perspective is needed to fully understand the biological complexities of this process as a polygenic trait. Nevertheless, it has been estimated that 74% of the variance in human eye colour can be explained by one interval on chromosome 15 that contains the OCA2 gene. Fine mapping of this region has identified a single base change rs12913832 T/C within intron 86 of the upstream HERC2 locus that explains almost all of this association with blue-brown eye colour. A model is presented whereby this SNP, serving as a target site for the SWI/SNF family member HLTF, acts as part of a highly evolutionary conserved regulatory element required for OCA2 gene activation through chromatin remodelling. Major candidate genes possibly effecting iris patterns are also discussed, including MITF and PAX6. PMID:19619260
Sturm, Richard A; Larsson, Mats
New Evidence for Infant Colour Categories
ERIC Educational Resources Information Center
Bornstein, Kessen, and Weiskopf (1976) reported that pre-linguistic infants perceive colour categorically for primary boundaries: Following habituation, dishabituation only occurred if the test stimulus was from a different adult category to the original. Here, we replicated this important study and extended it to include secondary boundaries,�
Franklin, Anna; Davies, Ian R. L.
Colour-dependent target detection by bees
The distance over which an object is detected by bees depends on the subtended visual angle and on spectral cues. At large angular subtenses detection is mediated only by chromatic cues. Achromatic targets, however, are also detectable. We investigated how chromatic and achromatic cues interact in detecting large-size targets. Coloured targets were used, with varied chromatic contrast that either did
C. Niggebr�gge; N. Hempel de Ibarra
The Coloured Product of the Sakaguchi Reaction
WE have already reported1 that the coloured product of the Sakaguchi reaction2 (between arginine and alpha-naphthol) behaves as a typical acid-base indicator, being red in alkali and yellow3 in acid. It has now been found that the compound behaves as an oxidation-reduction indicator also.
Kshirod R. Bhattacharya
Demonstration of the Colour Range of Indicators
ERIC Educational Resources Information Center
Describes the construction of a box that is filled with indicator of a particular concentration. A little acid is added to one side and a little alkali to the other so that the complete colour range of the indicator is observable. (GS)
Woods, G. T.
Colour Vision in Migraine: Selective Deficits for SCone Discriminations
Three studies are reported that explore colour perception in migraine. In each, sensitivity for colours detected selectively by the S-cones and the L- and M-cones was assessed separately. The first study assessed the discrimination of small colour differences using the Farnsworth-Munsell 100-hue test. The second assessed threshold detection for purple, yellow, red and green targets on five equiluminant background colours.
AJ Shepherd
Recent Advances in 1-3 Piezoelectric Polymer Composite Transducer Technology for AUV\\/UUV Acoustic Imaging Applications
Over the past 5 years, the use of 1-3 piezoelectric polymer composite has been studied under various U.S. Navy-funded transducer research programs. As a transduction material, the 1-3 piezoelectric composite offers many advantages for autonomous undersea vehicles\\/unmanned undersea vehicle (AUV\\/UUV) imaging array construction. Broad bandwidth, high transmit\\/receive response, low cost of fabrication, mechanical ruggedness, and the ability to form conformal
Kim C. Benjamin
Colour based human motion tracking for home-based rehabilitation
Abstract - In this paper, we propose a colour based trackingal gorithm for capturing the motionof hu man body parts for home-based rehabilitation. Different colour belts are attached to the bodyjo ints ofin terest andtra cked in the video sequence. The performance of the colour-based tracking algorithm is ,analysed by comparing the tracking results with the results from a commercial
Yaqin Tao; Huosheng Hu
Visual effects of wall colours in living rooms
The visual effects of wall colours were quantified as the purpose of basic research to create a comfortable atmosphere by applying the visual effects of colours to interior colour design. The experiment was conducted at three different temperatures of 10, 25 and 40�C, and at a constant relative humidity of 60%. Slides of 1\\/10-scale living room models of different wall
Colour constancy in the swallowtail butterfly Papilio xuthus.
We have recently shown that the Japanese yellow swallowtail butterfly Papilio xuthus uses colour vision when searching for food. In the field, these butterflies feed on nectar provided by flowers of various colours not only in direct sunlight but also in shaded places and on cloudy days, suggesting that they have colour constancy. Here, we tested this hypothesis. We trained newly emerged Papilio xuthus to feed on sucrose solution on a paper patch of a certain colour under white illumination. The butterflies were then tested under both white and coloured illumination. Under white illumination, yellow- and red-trained butterflies selected the correctly coloured patch from a four-colour pattern and from a colour Mondrian collage. Under four different colours of illumination, we obtained results that were fundamentally similar to those under white illumination. Moreover, we performed critical tests using sets of two similar colours, which were also correctly discriminated by trained butterflies under coloured illumination. Taken together, we conclude that the butterfly Papilio xuthus exhibits some degree of colour constancy when searching for food. PMID:11060214
Kinoshita, M; Arikawa, K
Evolutionary genetics of dorsal wing colour in Colias butterflies
The evolution of butterfly wing colouration is strongly affected by its multiple functions and by the correlated evolution of wing colour elements. Both factors may prevent local adaptation to ecological conditions. We investigated one aspect of wing colouration, the degree of dorsal wing melanization, in the butterfly Colias philodice eriphyle across an elevational gradient and its correlation with another aspect
J. Ellers; C. L. Boggs
Composite analysis of dust impacts on African easterly waves in the Moderate Resolution Imaging Spectrometer era
NASA Astrophysics Data System (ADS)
This study examines the synoptic scale impacts of African dust on easterly waves in the tropical northeast Atlantic. Moderate Resolution Imaging Spectrometer aerosol optical depth (AOD), National Oceanic and Atmospheric Administration products, and National Center for Environmental Prediction reanalysis fields in the Atlantic main hurricane development region (MDR) form the basis for statistical analysis of a limited set of cases objectively selected for the 2000-2008 hurricane seasons when thresholds are exceeded for sea surface temperature (SST), easterly wind shear, cyclonic vorticity, and upward motion. After ranking African easterly waves by AOD, the top (dusty) and bottom (clean) cases are studied as composite differences. African dust and subsidence cause temperatures to warm �3�C in the 700 hPa layer, while SSTs cause temperatures to cool, stabilizing the atmosphere. Increased AOD and strong (10 m s-1) 600 hPa easterly winds limit cloud efficiency through shear and oversupply of condensation nuclei. Vertical section composites demonstrate that warm dry subsident air coincides with the African dust plume in the latitudes 18�N-30�N. Hurricane reanalysis data indicate that higher AOD in the MDR reduces chances for the intensification of African easterly waves.
Jury, Mark R.; Santiago, Myrna J.
Determination of mixed-mode energy release rates in laminated carbon fiber composite structures using digital image correlation
NASA Astrophysics Data System (ADS)
Carbon fiber composites have recently seen a large scale application in industry due to its high strength and low weight. Despite numerous beneficial attributes of composite materials, they are subject to several unique challenges; the most prevalent and troubling is delamination fracture. This research program is focused on developing an appropriate damage model capable of analyzing microscopic stress strain growth at the crack tip of laminated composites. This thesis focuses on capturing and identifying the varying stress and strain fields, as well as other microstructural details and phenomena unique to crack tip propagation in carbon fiber panels using a novel mechanical characterization technique known as Digital Image Correlation (DIC).
Puishys, Joseph F., III
Monitoring of wildfires in boreal forests using large area AVHRR NDVI composite image data
NASA Technical Reports Server (NTRS)
Normalized difference vegetation index (NDVI) composite image data, produced from AVHRR data collected in 1990, were evaluated for locating and mapping the areal extent of wildfires in the boreal forests of Alaska during that year. A technique was developed to map forest fire boundaries by subtracting a late-summer AVHRR NDVI image from an early summer scene. The locations and boundaries of wildfires within the interior region of Alaska were obtained from the Alaska Fire Service, and compared to the AVHRR-derived fire-boundary map. It was found that AVHRR detected 89.5 percent of all fires with sizes greater than 2000 ha with no false alarms and that, for most cases, the general shape of the fire boundary detected by AVHRR matched those mapped by field observers. However, the total area contained within the fire boundaries mapped by AVHRR were only 61 percent of those mapped by the field observers. However, the AVHRR data used in this study did not span the entire time period during which fires occurred, and it is believed the areal estimates could be improved significantly if an expanded AVHRR data set were used.
Kasischke, Eric S.; French, Nancy H. F.; Harrell, Peter; Christensen, Norman L., Jr.; Ustin, Susan L.; Barry, Donald
Automated segmentation of muscle and adipose tissue on CT images for human body composition analysis
NASA Astrophysics Data System (ADS)
The ability to compute body composition in cancer patients lends itself to determining the specific clinical outcomes associated with fat and lean tissue stores. For example, a wasting syndrome of advanced disease associates with shortened survival. Moreover, certain tissue compartments represent sites for drug distribution and are likely determinants of chemotherapy efficacy and toxicity. CT images are abundant, but these cannot be fully exploited unless there exist practical and fast approaches for tissue quantification. Here we propose a fully automated method for segmenting muscle, visceral and subcutaneous adipose tissues, taking the approach of shape modeling for the analysis of skeletal muscle. Muscle shape is represented using PCA encoded Free Form Deformations with respect to a mean shape. The shape model is learned from manually segmented images and used in conjunction with a tissue appearance prior. VAT and SAT are segmented based on the final deformed muscle shape. In comparing the automatic and manual methods, coefficients of variation (COV) (1 - 2%), were similar to or smaller than inter- and intra-observer COVs reported for manual segmentation.
Chung, Howard; Cobzas, Dana; Birdsell, Laura; Lieffers, Jessica; Baracos, Vickie
Monitoring of wildfires in boreal forests using large area AVHRR NDVI composite image data
Normalized difference vegetation index (NDVI) composite image data, produced from AVHRR data collected in 1990, were evaluated for locating and mapping the areal extent of wildfires in the boreal forests of Alaska during that year. A technique was developed to map forest fire boundaries by subtracting a late-summer AVHRR NDVI image from an early summer scene. The locations and boundaries of wildfires within the interior region of Alaska were obtained from the Alaska Fire Service, and compared to the AVHRR-derived fire-boundary map. It was found that AVHRR detected 89.5% of all fires with sizes greater than 2,000ha with no false alarms and that, for most cases, the general shape of the fire boundary detected by AVHRR matched those mapped by field observers. However, the total area contained within the fire boundaries mapped by AVHRR were only 61% of those mapped by the field observers. However, the AVHRR data used in this study did not span the entire time period during which fires occurred, and it is believed the areal estimates could be improved significantly if an expanded AVHRR data set were used.
Kasischke, E.S.; French, N.H.F. (Environmental Research Inst. of Michigan, Ann Arbor (United States)); Harrell, P.; Christensen, N.L. Jr. (Duke Univ., Durham, NC (United States)); Ustin, S.L. (Univ. of California, Davis (United States)); Barry, D. (U.S. Bureau of Land Management, Fairbanks, AK (United States))
The coding of uniform colour figures in monkey visual cortex
Psychophysical studies indicate that perception of the colour and brightness of a surface depends on neural signals evoked by the borders of the surface rather than its interior. The visual cortex emphasizes contrast borders, but it is unclear whether colour surface signals also exist, whether colour border signals are orientation selective or mainly non-oriented, and whether cortical processing tends to separate colour and form information. To address these questions we examined the representation of uniform colour figures by recording single neuron activity from areas V1 and V2 in alert macaque monkeys during behaviourally induced fixation. Three aspects of coding were quantified: colour, orientation and edge selectivity. The occurrence of colour selectivity was not correlated with orientation or edge selectivity. The fraction of colour-selective cells was the same (64 % in layers 2 and 3 of V1, 45 % in V2) for oriented and non-oriented cells, and for edge-selective and surface-responsive cells. Oriented cells were often highly selective in colour space, and about 40 % of them were selective for edge polarity or border ownership. Thus, contrary to the idea of feature maps, colour, orientation and edge polarity are multiplexed in cortical signals. The results from V2 were similar to those from upper-layer V1, indicating that cortical processing does not strive to separate form and colour information. Oriented cells were five times more frequent than non-oriented cells. Thus, the vast majority of colour-coded cells are orientation tuned. Based on response profiles across a 4 deg square figure, and the relative frequency of oriented and non-oriented cells, we estimate that the cortical colour signal is 5�6 times stronger for the edges than for the surface of the figure. The frequency of oriented colour cells and their ability to code edge polarity indicate that these cells play a major role in the representation of surface colour.
Friedman, Howard S; Zhou, Hong; von der Heydt, Rudiger
Capturing Natural-Colour 3D Models of Insects for Species Discovery and Diagnostics.
Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity-past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control. PMID:24759838
Nguyen, Chuong V; Lovell, David R; Adcock, Matt; La Salle, John
Seeing depth in colour: more than just what meets the eyes.
Novel binocular depth illusions obtained from two-dimensional colour images are presented. It is demonstrated that the magnitude of these illusions is based on transverse chromatic aberration (TCA), however, the depth obtained cannot be observed unless specific conditions are met even if the TCA is present. Some form of perceptual organization occurring at and/or beyond the binocular fusion site of the brain, is required for some of these effects to occur. An example of a paradoxical finding leading to this conclusion is the observation that under some conditions the same colour can be perceived on separate depth planes while spatially adjacent colours from opposing ends of the visible spectrum (i.e. red and blue or green) can be perceived on the same depth plane simultaneously within the same image. Further, results show that some form of reference plane is required by the brain to use the colour induced disparity, without which, depth cannot be perceived even if the disparity information is present. This phenomenon is spatially tuned for medium to high frequency components and is still detectable under isoluminant conditions which would support the notion that it requires information from the parvocellular pathway. Binocular lustre and rivaldepth are ruled out as being significant factors in the effect. It is argued that this phenomenon represents an instance of global interactive processes induced by TCA while previous studies on chromostereopsis have concentrated on local aspects. Results of the present study may explain why under certain situations depth can be perceived in coloured images and not under other circumstances where TCA is still present. PMID:8184561
Faubert, J
Capturing Natural-Colour 3D Models of Insects for Species Discovery and Diagnostics
Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity�past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens �from all angles� and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. (�Natural-colour� is used to contrast with �false-colour�, i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control.
Nguyen, Chuong V.; Lovell, David R.; Adcock, Matt; La Salle, John
Differences in pigment composition, photosynthetic rates and chlorophyll fluorescence images of sun and shade leaves of four tree species
The differential pigment composition and photosynthetic activity of sun and shade leaves of deciduous (Acer pseudoplatanus, Fagus sylvatica, Tilia cordata) and coniferous (Abies alba) trees was comparatively determined by studying the photosynthetic rates via CO2 measurements and also by imaging the Chl fluorescence decrease ratio (RFd), which is an in vivo indicator of the net CO2 assimilation rates. The thicker
Hartmut K. Lichtenthaler; Alexander A?; Michal V. Marek; Ji?� Kalina; Otmar Urban
Diagnosing synaesthesia with online colour pickers: maximising sensitivity and specificity.
The most commonly used method for formally assessing grapheme-colour synaesthesia (i.e., experiencing colours in response to letter and/or number stimuli) involves selecting colours from a large colour palette on several occasions and measuring consistency of the colours selected. However, the ability to diagnose synaesthesia using this method depends on several factors that have not been directly contrasted. These include the type of colour space used (e.g., RGB, HSV, CIELUV, CIELAB) and different measures of consistency (e.g., city block and Euclidean distance in colour space). This study aims to find the most reliable way of diagnosing grapheme-colour synaesthesia based on maximising sensitivity (i.e., ability of a test to identify true synaesthetes) and specificity (i.e., ability of a test to identify true non-synaesthetes). We show, applying ROC (receiver operating characteristics) to binary classification of a large sample of self-declared synaesthetes and non-synaesthetes, that the consistency criterion (i.e., cut-off value) for diagnosing synaesthesia is considerably higher than the current standard in the field. We also show that methods based on perceptual CIELUV and CIELAB colour models (rather than RGB and HSV colour representations) and Euclidean distances offer an even greater sensitivity and specificity than most currently used measures. Together, these findings offer improved heuristics for the behavioural assessment of grapheme-colour synaesthesia. PMID:23458658
Rothen, Nicolas; Seth, Anil K; Witzel, Christoph; Ward, Jamie
Generation of Composite Dose and Biological Effective Dose (BED) Over Multiple Treatment Modalities and Multistage Planning Using Deformable Image Registration
Currently there are no commercially available tools to generate composite plans across different treatment modalities and/or different planning image sets. Without a composite plan, it may be difficult to perform a meaningful dosimetric evaluation of the overall treatment course. In this paper, we introduce a method to generate composite biological effective dose (BED) plans over multiple radiotherapy treatment modalities and/or multistage plans, using deformable image registration. Two cases were used to demonstrate the method. Case I was prostate cancer treated with intensity-modulated radiation therapy (IMRT) and a permanent seed implant. Case II involved lung cancer treated with two treatment plans generated on two separate computed tomography image sets. Thin-plate spline or optical flow methods were used as appropriate to generate deformation matrices. The deformation matrices were then applied to the dose matrices and the resulting physical doses were converted to BED and added to yield the composite plan. Cell proliferation and sublethal repair were considered in the BED calculations. The difference in BED between normal tissues and tumor volumes was accounted for by using different BED models, {alpha}/{beta} values, and cell potential doubling times. The method to generate composite BED plans presented in this paper provides information not available with the traditional simple dose summation or physical dose summation. With the understanding of limitations and uncertainties of the algorithms involved, it may be valuable for the overall treatment plan evaluation.
Zhang, Geoffrey [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL (United States) and Department of Medical Radiological Technology, China Medical University, Taiwan (China)], E-mail: email@example.com; Huang, T-C; Feygelman, Vladimir; Stevens, Craig; Forster, Kenneth [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL (United States) and Department of Medical Radiological Technology, China Medical University, Taiwan (China)
Colour biases in territorial aggression in a Neotropical cichlid fish.
Discrete colour morphs have provided important insights into the evolution of phenotypic diversity. One of the mechanisms that can help to explain coexistence of ecologically similar colour morphs and incipient species is (colour) biased aggression, which has the potential to promote continued existence of the morphs in a frequency-dependent manner. I addressed colour biases in territorial aggression in a field-based study on a Neotropical cichlid fish species, Amphilophus sagittae, which has two ecologically indistinguishable colour morphs that mate assortatively. I found that A. sagittae, in particular females, were more aggressive towards models of their own colour than those mimicking colours of the other morph. Such a behavioural pattern should result in a selection regime that benefits the rarer morph, and hence could help explain how novel, rare phenotypes may avoid competitive exclusion. PMID:24414236
Lehtonen, Topi K
Thermodynamics of two-colour QCD
NASA Astrophysics Data System (ADS)
We discuss the thermodynamics of two-colour QCD with four flavours of staggered quarks on 8 3 � 4 and 16 3 � 4 lattices. In our simulations we use the Naik action for the fermions and a (1,2) tree-level improved gauge action. We analyze the deconfinement and chiral phase transitions for four different quark masses (m=0.1,0.05,0.025,0.015). Contrary to three-colour QCD the peak in the Polyakov loop susceptibility decreases with decreasing quark mass. This reflects an early breaking of the string in the heavy quark potential, which we verify explicitly by calculating the heavy quark potential at finite temperature using Polyakov loop correlations.
Kaczmarek, O.; Karsch, F.; Laermann, E.
Evaluation of preferred lightness rescaling methods for colour reproduction
NASA Astrophysics Data System (ADS)
In cross-media colour reproduction, it is common goal achieving media-relative reproduction. From the ICC specification, this often accomplished by linearly scaling XYZ data so that the media white of the source data matches that of the destination data. However, in this approach the media black points are not explicitly aligned. To compensate this problem, it is common to apply a black point compensation (BPC) procedure to improve the mapping of the black points. First, three lightness rescaling methods were chosen: linear, sigmoidal and spline. CIECAM02 was also implemented in an approach of a lightness rescaling method; simply, lightness values from results produced by CIECAM02 handle as if reproduced lightness values of an output image. With a chosen image set, above five different methods were implemented. A paired-comparison psychophysical experiment was performed to evaluate performances of the lightness rescaling methods. In most images, the Adobe's BPC, linear and Spline lightness rescaling methods are preferred over the CIECAM02 and sigmoidal lightness rescaling methods. The confidence interval for the single image set is +/-0.36. With this confidence interval, it is difficult to conclude the Adobe BPC' method works better, but not significantly so. However, for the overall results, as every single observation is independent to each other, the result was presented with the confidence interval of +/-0.0763. Based on the overall result, the Adobe's BPC method performs best.
Chang, Yerin
How to Calculate Colourful Cross Sections Efficiently
Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.
Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank
Designs for two-colour microarray experiments
Designs for two-colour microarray experiments can be viewed as block designs with two treatments per block. Explicit formulae for the A- and D-criteria are given for the case that the number of blocks is equal to the number of treatments. These show that the A- and D-optimality criteria conflict badly if there are 10 or more treatments. A similar analysis
R. A. Bailey
Colour Phenomena in Ultra-Violet Vision
THE note by N. I. Pinegin1 suggests a more detailed discussion of the relation between the threshold intensities for scotopic and photopic vision in the ultra-violet. The threshold ratio Tp\\/Ts is a measure of the intensity range, often misleadingly called `photochromatic interval', in which the visual impression is free from the specific colour sensation. This intensity range is a marked
E. E. Schneider
System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns
NASA Technical Reports Server (NTRS)
A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.
Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)
System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns
NASA Technical Reports Server (NTRS)
A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.
Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)
Colour Magnitude Diagrams of Transiting Exoplanets
NASA Astrophysics Data System (ADS)
Colour-Magnitude diagrams form a traditional way of representing luminous objects in the Universe and compare them to each others. Here, the photometric distances of 44 transiting exoplanetary systems were estimated. For seven of those, parallaxes confirm the methodology. From the combination of those measurements with fluxes obtained while planets were occulted by their host stars, colour-magnitude diagrams are composed in the near and mid IR. When possible, planets are plotted with field brown dwarfs who often have similar sizes and equilibrium temperatures, thus offering a natural empirical comparison sample. Exoplanets are also compared to the expected loci of pure blackbodies. In general planets do not agree with the brown dwarfs sequences, and neither do they match blackbodies. It is however possible to affirm that they are not featureless and that they display an increasing diversity in colour with decreasing intrinsic luminosity. A missing source of absorption within the [4.5 ?m] band, for some planets, would generally reconcile hot Jupiters with brown dwarfs� cool atmospheres. Alternatively, measuring the emission of gas giants cooler than 1 000 K would disentangle whether planets� atmospheres behave like brown dwarfs� atmospheres, like blackbodies, or whether they form their own sequence.
Triaud, Amaury H. M. J.
Artist's colour rendering of HDR scenes in 3D Mondrian colour-constancy experiments
NASA Astrophysics Data System (ADS)
The presentation provides an update on ongoing research using three-dimensional Colour Mondrians. Two still life arrangements comprising hand-painted coloured blocks of 11 different colours were subjected to two different lighting conditions of a nearly uniform light and directed spotlights. The three-dimensional nature of these test targets adds shadows and multiple reflections, not found in flat Mondrian targets. Working from exactly the same pair of scenes, an author painted them using watercolour inks and paints to recreate both LDR and HDR Mondrians on paper. This provided us with a second set of appearance measurements of both scenes. Here we measured appearances by measuring reflectances of the artist's rendering. Land's Colour Mondrian extended colour constancy from a pixel to a complex scene. Since it used a planar array in uniform illumination, it did not measure the appearances of real life 3-D scenes in non-uniform illumination. The experiments in this paper, by simultaneously studying LDR and HDR renditions of the same array of reflectances, extend Land's Mondrian towards real scenes in non-uniform illumination. The results show that the appearances of many areas in complex scenes do not correlate with reflectance.
Parraman, Carinna E.; McCann, John J.; Rizzi, Alessandro
On the effect of helium enhancement on bolometric corrections and Teff-colour relations
We evaluate the effects that variations in He content have on bolometric corrections and T_eff-colour relations. To do this, we computed ATLAS9 model atmospheres and spectral energy distributions for effective temperatures ranging from 3500 K to 40 000 K for dwarfs and from 3500 K to 8000 K for giants, considering both ``He-non-enhanced'' and ``He-enhanced'' compositions. The variations in He
L. Girardi; F. Castelli; G. Bertelli; E. Nasi
Digital-image-correlation-based experimental stress analysis of reinforced concrete beams strengthened using carbon composites
NASA Astrophysics Data System (ADS)
The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.
Helm, Jeffrey; Kurtz, Stephen
Digital-image-correlation-based experimental stress analysis of reinforced concrete beams, strengthened using carbon composites
NASA Astrophysics Data System (ADS)
The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.
Helm, Jeffrey; Kurtz, Stephen
Two-dimensional and three-dimensional GPR imaging of wood and fiber reinforced polymer composites
NASA Astrophysics Data System (ADS)
Subsurface defects in wooden logs such as knots, decays, splits, embedded metallic nails and bullets are of major concern to timber saw mills. Presence of these defects decreases the value of the sawn lumber boards. Also, the factory down time and operation cost increases significantly whenever the saw blade is damaged by encountering embedded metals during the sawing process. This study has been conducted to assess the possibility of detecting subsurface defects in logs using Ground Penetrating Radar (GPR) before the sawing process. GPR radargrams obtained from several wooden logs using different scanning techniques and analysis methods were investigated. These methods included scanning of both the circular and canted logs and using 900 MHz and 1600 MHz frequency antennas. The GPR radargrams obtained using different scanning configurations and antenna frequencies were analyzed using both 2D and 3D imaging techniques. The study showed that metals and defects inside the log can be precisely detected and located using GPR. Moreover, use of newer 3D interpretation techniques showed the possibility of determining even the orientation and extent of the defects inside the log. Similar to wooden logs, there is also a need to identify the defects within the FRP composites. Debonds and entrapped moisture in the FRP wrapped members often reduce their strength and stiffness performance. Hence the 2D and 3D methodology developed for wooden logs was extended to FRP composites for subsurface defect detection. The study showed that GPR based system is suitable for use in timber saw mills to map hidden defects (e.g., knots, decays) and foreign objects (e.g., metallic nails) in wooden logs prior to sawing, so that the yield of high-value defect-free lumber can be maximized. It can also be used as a fast nondestructive tool to detect subsurface moisture and debonds and monitor the in-situ condition of FPR wrapped members.
Pyakurel, Sandeep
Adding New Colours to Interferometry
NASA Astrophysics Data System (ADS)
Another vital step has been accomplished as planned towards full operation of the ESO Very Large Telescope Interferometer (VLTI) at the Paranal Observatory in Chile, one of the world's foremost astronomical facilities. In the night of March 20-21, 2004, a team of astronomers and engineers from France, Italy, Germany and ESO celebrated the successful assembly and completion of the first on-line tests of the latest of the first-generation VLTI instruments, the Astronomical Multiple BEam Recombiner (AMBER). They combined the two beams of light from the southern star Theta Centauri from two test telescopes ("siderostats" with 40-cm aperture, cf. ESO PR 06/01) to produce strong and clear interferometric fringes. Equally successful observations were then obtained on the bright star Sirius, and consistently repeated during the following nights. A joint project This is the most promising result of about 7 years of dedicated work by a team of over 40 astronomers and engineers. The AMBER instrument has been developed by a European consortium of seven research institutes in three ESO member countries, the main partners being: Laboratoire d'Astrophysique de Grenoble (LAOG), Laboratoire Universitaire d'Astrophysique de Nice (LUAN) and Observatoire de la C�te d'Azur in France, Max-Planck-Institut f�r Radioastronomie (MPIfR) in Bonn, Germany, and Osservatorio Astrofisico di Arcetri (OAA; part of INAF, the Italian National Institute for Astrophysics) in Florence, Italy. The total cost of AMBER is of the order of 5.9 million Euros, mostly contributed by the members of the consortium. It was built through an agreement with ESO, which rewards the consortium solely with guaranteed observing time. According to the contract, the consortium will receive 60 observing nights to be spread among two or three of the four 8.2-m VLT Unit Telescopes and 130 nights with the four Auxiliary Telescopes over a period of eight years. AMBER: soon to join three light beams at once ESO PR Photo 09a/04 ESO PR Photo 09a/04 AMBER at the VLT Interferometric Laboratory [Preview - JPEG: 534 x 400 pix - 68k] [Normal - JPEG: 1067 x 800 pix - 665k] Caption: ESO PR Photo 09a/04 shows the AMBER instrument in the VLT Interferometric Laboratory at Paranal. The AMBER instrument is mounted on a 4.2 x 1.5 m precision optical table, placed in the VLT Interferometric Laboratory at the top of the Paranal mountain, cf. PR Photo 09/04. The total shipping weight of the instrument and its extensive associated electronics was almost 4 tons. AMBER is the latest addition to the VLTI and completes the planned set of first-generation instruments for this facility. It continues the success story of the interferometric mode of the VLT, following the unique initial scientific results obtained by the VINCI and MIDI instruments, the installation of the first MACAO adaptive optics systems and the recent arrival of the first 1.8-m Auxiliary Telescope at Paranal (ESO PR 01/04). The interferometric technique can achieve images, as sharp as those of a telescope with a diameter equivalent to the distance between the telescopes in the interferometer. For the VLTI, this distance can be as large as 205 meters, resulting in a resolution of 0.001 arcsec in the near-infrared spectral region (at 1 ?m wavelength). The latter measure corresponds to about 2 metres on the surface of the Moon. AMBER is a very powerful complement to the other instruments already installed at the VLTI and offered to the astronomical community. AMBER is indeed sensitive in the near-infrared wavelength region of 1 to 2.5 microns while the present instrument, MIDI, covers the 8 to 13 microns range. Moreover, AMBER will be able to perform spectroscopic measurements with a spectral resolution up to 10,000. ESO PR Photo 09b/04 ESO PR Photo 09b/04 The AMBER instrument (detail) [Preview - JPEG: 435 x 400 pix - 74k] [Normal - JPEG: 870 x 800 pix - 722k] Caption: ESO PR Photo 09b/04 shows in the foreground some of the mirrors and optical fibers (yellow cables), as well as the dichroic mirrors by means of which the light beams
Imaging of Optoelectronic Processes in Nanometer-Scale Structures and Composites
NASA Astrophysics Data System (ADS)
There is growing interest in the underlying physical processes in optoelectronic devices based on composites of organic and inorganic electronic materials, including low-cost large-area solid-state solar cell and light emitting devices, photodetectors, and optical memories. Such devices are often thin-film multilayer structures involving nanostructured polymeric and/or crystalline organic layers and inorganic layers supported on conducting/transparent indium tin oxide glass electrodes. The unique electrooptic behavior of these devices and essential physical processes such as charge injection/separation at interfaces, charge and exciton mobilities, exciton decay processes, and exciton/charge-carrier interactions are often intimately controlled by the detailed nanostructured morphologies of the system. There is a need for experimental tools that allow for imaging (spatial resolution) of the physical properties and processes associated with nanometer scale structures. Ideally, simultaneous imaging of the layer morphology and physical processes would ultimately allow for a direct correlation of morphology and device physics in a functional device, device prototype, or isolated nanostructure. Nanometer scale structures are expected to impact broad areas of electronics and optics technology. The realization of the technological applications requires a greater understanding of how nanostructures are synthesized and fabricated and importantly requires a greater understanding of the intrinsic and potentially unique physical properties of nanostructures. Here we present recent results where two complimentary new methods are used to spatially and temporally resolve optoelectronic properties and processes in nanostructured thin films. Electric field modulated near-field scanning optical microscopy (NSOM) and light-modulated scanning electrostatic potential microscopy (SEPM) are used to investigate self-organizing liquid crystalline molecular semiconductors and photoconductors, and inorganic semiconductor particle/conducting polymer nanocomposites.
Adams, David M.
A shared chemical basis of avian host-parasite egg colour mimicry.
Avian brood parasites lay their eggs in other birds' nests and impose considerable fitness costs on their hosts. Historically and scientifically, the best studied example of circumventing host defences is the mimicry of host eggshell colour by the common cuckoo (Cuculus canorus). Yet the chemical basis of eggshell colour similarity, which impacts hosts' tolerance towards parasitic eggs, remains unknown. We tested the alternative scenarios that (i) cuckoos replicate host egg pigment chemistry, or (ii) cuckoos use alternative mechanisms to produce a similar perceptual effect to mimic host egg appearance. In parallel with patterns of similarity in avian-perceived colour mimicry, the concentrations of the two key eggshell pigments, biliverdin and protoporphyrin, were most similar between the cuckoo host-races and their respective hosts. Thus, the chemical basis of avian host-parasite egg colour mimicry is evolutionarily conserved, but also intraspecifically flexible. These analyses of pigment composition reveal a novel proximate dimension of coevolutionary interactions between avian brood parasites and hosts, and imply that alternative phenotypes may arise by the modifications of already existing biochemical and physiological mechanisms and pathways. PMID:21920975
Igic, Branislav; Cassey, Phillip; Grim, Tom�s; Greenwood, David R; Mosk�t, Csaba; Rutila, Jarkko; Hauber, Mark E
Filling-in with colour: different modes of surface completion.
We investigated the figural dynamics of filling-in processes in figures with more than one possible figure-ground organisation. Using a central disk and two concentric rings as well as similar stimuli consisting of three nested squares or parallel stripes, we tested for filling-in with different equiluminant colour combinations. We observed four modes of filling-in: First, in most of the cases, the inner ring assumed the colour of the central disk and outer ring (M1). Second, the central disk became filled-in with the colour of the inner ring, without any colour change on the outer ring (M2). Third, in a first step, the colour of the inner ring spread onto the central disk; then, in a second step, the colour of the outer ring spread over the whole stimulus (M3). This two step filling-in process has not been reported so far. Fourth, a mode (M4) was sometimes observed that was characterised by the central disk and outer ring assuming the colour of the inner ring. Thus, colour filling-in or colour spreading proceeded both in a centripetal (periphery to fovea) as well as a centrifugal direction. The colours red and yellow proved to be stronger inducers than blue and green. Conversely, the latter colours became filled-in more easily than the former. The filled-in colour was always that of the inducing stimulus, i.e., there was no colour mixture. This suggests a long-range, neural process underlying filling-in under these conditions. PMID:16197977
Hamburger, Kai; Prior, Helmut; Sarris, Viktor; Spillmann, Lothar
Composite Artistry Meets Facial Recognition Technology: Exploring the Use of Facial Recognition Technology to Identify Composite Images.
National Technical Information Service (NTIS)
Forensic art has been used for decades as a tool for law enforcement. When crime witnesses can provide a suspect description, an artist can create a composite drawing in hopes that a member of the public will recognize the subject. In cases where a suspec...
T. L. Montgomery
Computer vision-based analysis of foods: a non-destructive colour measurement tool to monitor quality and safety.
Computer vision-based image analysis has been widely used in food industry to monitor food quality. It allows low-cost and non-contact measurements of colour to be performed. In this paper, two computer vision-based image analysis approaches are discussed to extract mean colour or featured colour information from the digital images of foods. These types of information may be of particular importance as colour indicates certain chemical changes or physical properties in foods. As exemplified here, the mean CIE a* value or browning ratio determined by means of computer vision-based image analysis algorithms can be correlated with acrylamide content of potato chips or cookies. Or, porosity index as an important physical property of breadcrumb can be calculated easily. In this respect, computer vision-based image analysis provides a useful tool for automatic inspection of food products in a manufacturing line, and it can be actively involved in the decision-making process where rapid quality/safety evaluation is needed. PMID:24288215
Mogol, Bur�e Ata�; G�kmen, Vural
A novel segmentation method to identify left ventricular infarction in short-axis composite strain-encoded magnetic resonance images
NASA Astrophysics Data System (ADS)
Composite Strain Encoding (CSENC) is a new Magnetic Resonance Imaging (MRI) technique for simultaneously acquiring cardiac functional and viability images. It combines the use of Delayed Enhancement (DE) and the Strain Encoding (SENC) imaging techniques to identify the infracted (dead) tissue and to image the myocardial deformation inside the heart muscle. In this work, a new unsupervised segmentation method is proposed to identify infarcted left ventricular tissue in the images provided by CSENC MRI. The proposed method is based on the sequential application of Bayesian classifier, Otsu's thresholding, morphological opening, radial sweep boundary tracing and the fuzzy C-means (FCM) clustering algorithm. This method is tested on images of twelve patients with and without myocardial infarction (MI) and on simulated heart images with various levels of superimposed noise. The resulting clustered images are compared with those marked up by an expert cardiologist who assisted in validating results coming from the proposed method. Infarcted myocardium is correctly identified using the proposed method with high levels of accuracy and precision.
Algohary, Ahmad O.; Metwally, Muhammad K.; El-Bialy, Ahmed M.; Kandil, Ahmed H.; Osman, Nael F.
Composite Amplitude Modulated Phase Only Filter Based Detection and Tracking of the Back-Reflection of KDP Images
An algorithm for determining the position of the KDP back-reflection image was developed. It was compared to a centroid-based algorithm. While the algorithm based on centroiding exhibited a radial standard deviation of 9 pixels, the newly proposed algorithm based on classical matched filtering (CMF) and a Gaussian fit to correlation peak provided a radial standard deviation of less than 1 pixel. The speed of the peak detection was improved from an average of 5.5 seconds for Gaussian fit to 0.022 seconds by using a polynomial fit. The performance was enhanced even further by utilizing a composite amplitude modulated phase only filter; producing a radial standard deviation of 0.27 pixels. The proposed technique was evaluated on 900+ images with varying degrees of noise and image amplitude as well as real National Ignition Facility (NIF) images.
Awwal, A S; McClay, W A; Ferguson, S W; Candy, J V; Salmon, J T; Wegner, P J
Aggregate colour centres in impurity LiF crystals
LiF crystals with colour centres exhibiting a zero-phonon line (ZPL) at 1080 nm in absorption and luminescence are studied. The decay time of luminescence of colour centres at 10 K is 260 - 280 ns, the ZPL half-width is 4.7 cm{sup -1}, and colour centres are characterised by a weak electron - phonon interaction (the Huang - Rhys factor is S < 0.11). The polarisation analysis of luminescence showed that the transition dipole moments of colour centres are oriented along the crystal axes [100], [010], and [001]. The model of aggregate F{sub 4} colour centres having a spatial structure with three symmetry axes C{sub 2} may correspond to the colour centres studied in the paper. (active media. lasers)
Basiev, Tasoltan T; Karasik, Aleksandr Ya; Konyushkin, V A; Papashvili, A G; Pukhov, K K [Laser Materials and Technology Research Center, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Ermakov, I V; Gellermann, V [Department of Physics, University of Utah (United States)
Identification of "ever-cropped" land (1984-2010) using Landsat annual maximum NDVI image composites: Southwestern Kansas case study
A time series of 230 intra- and inter-annual Landsat Thematic Mapper images was used to identify land that was ever cropped during the years 1984 through 2010 for a five county region in southwestern Kansas. Annual maximum Normalized Difference Vegetation Index (NDVI) image composites (NDVIann-max) were used to evaluate the inter-annual dynamics of cropped and non-cropped land. Three feature images were derived from the 27-year NDVIann-max image time series and used in the classification: 1) maximum NDVI value that occurred over the entire 27 year time span (NDVImax), 2) standard deviation of the annual maximum NDVI values for all years (NDVIsd), and 3) standard deviation of the annual maximum NDVI values for years 1984�1986 (NDVIsd84-86) to improve Conservation Reserve Program land discrimination. Results of the classification were compared to three reference data sets: County-level USDA Census records (1982�2007) and two digital land cover maps (Kansas 2005 and USGS Trends Program maps (1986�2000)). Area of ever-cropped land for the five counties was on average 11.8 % higher than the area estimated from Census records. Overall agreement between the ever-cropped land map and the 2005 Kansas map was 91.9% and 97.2% for the Trends maps. Converting the intra-annual Landsat data set to a single annual maximum NDVI image composite considerably reduced the data set size, eliminated clouds and cloud-shadow affects, yet maintained information important for discriminating cropped land. Our results suggest that Landsat annual maximum NDVI image composites will be useful for characterizing land use and land cover change for many applications.
Maxwell, Susan K.; Sylvester, Kenneth M.
Identification of "ever-cropped" land (1984-2010) using Landsat annual maximum NDVI image composites: Southwestern Kansas case study.
A time series of 230 intra- and inter-annual Landsat Thematic Mapper images was used to identify land that was ever cropped during the years 1984 through 2010 for a five county region in southwestern Kansas. Annual maximum Normalized Difference Vegetation Index (NDVI) image composites (NDVI(ann-max)) were used to evaluate the inter-annual dynamics of cropped and non-cropped land. Three feature images were derived from the 27-year NDVI(ann-max) image time series and used in the classification: 1) maximum NDVI value that occurred over the entire 27 year time span (NDVI(max)), 2) standard deviation of the annual maximum NDVI values for all years (NDVI(sd)), and 3) standard deviation of the annual maximum NDVI values for years 1984-1986 (NDVI(sd84-86)) to improve Conservation Reserve Program land discrimination.Results of the classification were compared to three reference data sets: County-level USDA Census records (1982-2007) and two digital land cover maps (Kansas 2005 and USGS Trends Program maps (1986-2000)). Area of ever-cropped land for the five counties was on average 11.8 % higher than the area estimated from Census records. Overall agreement between the ever-cropped land map and the 2005 Kansas map was 91.9% and 97.2% for the Trends maps. Converting the intra-annual Landsat data set to a single annual maximum NDVI image composite considerably reduced the data set size, eliminated clouds and cloud-shadow affects, yet maintained information important for discriminating cropped land. Our results suggest that Landsat annual maximum NDVI image composites will be useful for characterizing land use and land cover change for many applications. PMID:22423150
Maxwell, Susan K; Sylvester, Kenneth M
Multisource Classification of Color and Hyperspectral Images Using Color Attribute Profiles and Composite Decision Fusion
In this work, we treat the problem of combined classification of a high spatial resolution color image and a lower spatial resolution hyperspectral image of the same scene. The problem is particularly challenging, since we aim for classification maps at the spatial resolution of the color image. Contextual information is obtained from the color image by introducing Color Attribute Profiles
Guy Thoonen; Zahid Mahmood; Stijn Peeters; Paul Scheunders
NASA Astrophysics Data System (ADS)
Particle distribution and hot workability of an in situ Al-TiCp composite were investigated. The composite was fabricated by an in situ casting method using the self-propagating high-temperature synthesis of an Al-Ti-C system. Hot-compression tests were carried out, and power dissipation maps were constructed using a dynamic material model. Small globular TiC particles were not themselves fractured, but the clustering and grain boundary segregation of the particles contributed to the cracking of the matrix by causing the debonding of matrix/particle interfaces and providing a crack propagation path. The efficiency of power dissipation increased with increasing temperature and strain rate, and the maximum efficiency was obtained at a temperature of 723 K (450 �C) and a strain rate of 1/s. The microstructural mechanism occurring in the maximum efficiency domain was dynamic recrystallization. The role of particles in the plastic flow and the microstructure evolution were discussed.
Kim, Su-Hyeon; Cho, Young-Hee; Lee, Jung-Moo
NASA Astrophysics Data System (ADS)
Ca3Co4O9 is one of the most promising p-type thermoelectric materials because of its high dimensionless figure of merit ZT. However, polycrystalline Ca3Co4O9 ceramics shows lower ZT value than that for single crystal Ca3 Co4O9 due to its higher electrical resistivity ?. Mikami et al. have reported that the addition of Ag to Ca3Co4O9 ceramics could successfully reduce ? and enhance the power factor. On the other hand, Ohtaki et al. reported that a composite structure could be highly effective to reduce ? for ZnO dually doped with Al and Ga. In this work, we tried to enhance the power factor and reduce ? by forming Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composite structure. As a result, the ZT value for Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composites reached 0.164 at 700 �C, which was 40 % higher than the value for Ca3Co4O9.
Obata, Kohei; Chonan, Yasunori; Komiyama, Takao; Abe, Kazunori; Aoyama, Takashi; Yamaguchi, Hiroyuki; Sugiyama, Shigeaki
Perceptual organization in colour perception: Inverting the gamut expansion effect
In the well-known gamut expansion effect, uniformly coloured target patches are perceived as more colourful when they are embedded in a uniform grey surround than when they are embedded in a variegated one. Here, we provide a demonstration showing that this effect can be inverted when the uniformly coloured target patches are replaced by variegated ones. This observation suggests that the gamut expansion effect is due to mechanisms of transparency perception rather than due to contrast adaptation.
Ekroll, Vebj?rn; Faul, Franz
One blue colour channel or two?
Contrary to the general belief that the yellow-blue mechanism has lower spatial resolution than the red-green mechanism, it has been recently claimed that both mechanisms have similar spatial sensitivity (McKeefry et al, 2001 Vision Research 41 245-255). Studying high-spatial-frequency tritanopia (a colour illusion based on spatio-chromatic interactions in human vision), we found strong evidence for the existence of two blue mechanisms-with low and high spatial-frequency resolution. If confirmed, this may resolve the apparent paradox concerning spatial resolution of the yellow-blue mechanism. PMID:16178144
Logvinenko, Alexander D; Hutchinson, Sara J
A Milliprobe for PIXE and PIGE Analysis used for the Study of Colour-Zoned Tourmaline
NASA Astrophysics Data System (ADS)
A "milliprobe" system was implemented by using the focusing properties of a Van de Graaff accelerator, together with a collimator system including 1 mm diameter apertures, to impose the appropriate dimension to the beam spot. The scanning of the sample surface was achieved by X-Y movements of the sample holder (the Z axis being coincident with the beam direction). These movements were accomplished by a motorised X-Y table, with a travel of 25 mm � 25 mm, connected to the sample holder. This system was used to study specimens of the mineral tourmaline. Two samples, of the "watermelon" zoned tourmaline variety, originating from the Alto Ligonha pegmatite district in northern Mozambique, were analysed by the simultaneous use of PIXE (Proton-Induced X-Ray Emission) and PIGE (Proton-Induced Gamma-Ray Emission) techniques, in order to quantify their composition and try to establish a correlation between the elements (major and trace elements) and colour zoning. In order to validate the "milliprobe" analysis and study in more detail the frontier between zones of different colours, a microprobe analysis of the samples was also done. In this work, the mineralogical classification of the samples was accomplished. A correlation was established between the presence of Fe and green colour. It was also concluded that the presence of Mn by itself is not enough to lead to pink colour, which gives support to previous studies that claim that only Mn3+ and not the more common form Mn2+ is responsible for the pink colour.
Mateus, R.; Alves, L. C.; Jesus, A. P.; Faria, A. F.; Ribeiro, J. P.
Iron oxide nanoparticle-containing microbubble composites as contrast agents for MR and ultrasound dual-modality imaging.
Magnetic resonance (MR) and ultrasound (US) imaging are widely used diagnostic modalities for various experimental and clinical applications. In this study, iron oxide nanoparticle-embedded polymeric microbubbles were designed as multi-modal contrast agents for hybrid MR-US imaging. These magnetic nano-in-micro imaging probes were prepared via a one-pot emulsion polymerization to form poly(butyl cyanoacrylate) microbubbles, along with the oil-in-water (O/W) encapsulation of iron oxide nanoparticles in the bubble shell. The nano-in-micro embedding strategy was validated using NMR and electron microscopy. These hybrid imaging agents exhibited strong contrast in US and an increased transversal relaxation rate in MR. Moreover, a significant increase in longitudinal and transversal relaxivities was observed after US-induced bubble destruction, which demonstrated triggerable MR imaging properties. Proof-of-principle in�vivo experiments confirmed that these nanoparticle-embedded microbubble composites are suitable contrast agents for both MR and US imaging. In summary, these magnetic nano-in-micro hybrid materials are highly interesting systems for bimodal MR-US imaging, and their enhanced relaxivities upon US-induced destruction recommend them as potential vehicles for MR-guided US-mediated drug and gene delivery. PMID:21632103
Liu, Zhe; Lammers, Twan; Ehling, Josef; Fokong, Stanley; Bornemann, J�rg; Kiessling, Fabian; G�tjens, Jessica
A Visual Survey of Colour on Paper and Colour Changes During Exposure to Light
This paper presents how inkjet colour is affected by firstly the substrate and secondly exposure to light and the combination of both. The research uses both pigmented and dye based inks printed onto coated and uncoated fine art papers, and are subjected to light conditions that are constantly changing through out the day and consequently the year. Although benchmark conditions
Carinna Parraman
Colour contribution to children's wayfinding in school environments
NASA Astrophysics Data System (ADS)
The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled 100 primary school children aged seven and eight years old. The study was conducted in four phases. In the first phase, the participants were tested for familiarity with the experiment site and also for colour vision deficiencies by using Ishihara's tests for colour-blindness. In the second phase, they were escorted on the experiment route by the tester one by one, from one starting point to one end point and were asked to lead the tester to the end point by the same route. In the third phase, they were asked to describe verbally the route. In the final phase, they were asked to remember the specific colours at their correct locations. It was found that colour has a significant effect on children's wayfinding performances in school environments. However, there were no differences between different colours in terms of their remembrances in route finding tasks. In addition, the correct identifications of specific colours and landmarks were dependent on their specific locations. Contrary to the literature, gender differences were not found to be significant i