A control unit sets a first control value for causing a charge accumulation unit to execute a first accumulation and obtaining first image data and a second control value for causing the charge accumulation unit to execute a second accumulation and obtaining second image data, depending on whether an operation mode set by a setting unit executes image recognition processing based on image data obtained through accumulation by the charge accumulation unit. If the operation mode set by the setting unit does not execute the image recognition processing, the control unit sets the first and second control values to be different from each other, even if an object field has a constant luminance.

1. Field of the Invention
The present invention relates to an imaging apparatus and an exposure control method executing a light-metering operation by using an accumulation-type image sensor.
2. Description of the Related Art
An imaging apparatus such as a digital camera or a digital video camera generally requires a light-metering range of approximately −5 to +15, as Bv values in additive system of photographic exposure (APEX) units. Namely, such imaging apparatus has a light-metering dynamic range of approximately 20 levels. However, when an accumulation-type image sensor executes a light-metering operation, the dynamic range in a single accumulation operation is less than 20 levels.
To address this problem, there is a known technique of generating an image having a dynamic range greater than the dynamic range obtained in a single accumulation operation (imaging). Based on this technique, an identical scene is captured by an accumulation-type image sensor a plurality of times with different exposure levels, and obtained image signals are compounded. This technique is generally referred to as high dynamic range (HDR) imaging.
Similarly, various documents are proposing increasing the dynamic range of a light-metering apparatus using an accumulation-type light-sensitive element. For example, Japanese Patent Application Laid-Open No. 6-130462 discusses a light-metering apparatus using an accumulation-type light-sensitive element. When executing a light-metering operation, this apparatus alternately uses a prolonged charge accumulation time and a shortened charge accumulation time. In this way, even when the luminance difference in an object field is very large, the apparatus can obtain light-metering values from low to high luminance parts.
In addition, imaging apparatuses having an object tracking function are conventionally known. This function recognizes a main object within an imaging screen and automatically tracks the position of the main object. Use of this object tracking function continuously enables automatic focus adjustment control (AF control) or exposure control (AE control) on a moving main object.
Examples of an imaging apparatus having such object tracking function include an imaging apparatus having, other than an image sensor, a light-metering unit used for a light-metering operation, such as a single-lens reflex camera. Japanese Patent Application Laid-Open No. 7-110429 discusses an apparatus that tracks an object, based on light-metering data supplied from a light-metering unit.
In addition, Japanese Patent Application Laid-Open No. 2011-35765 discusses a tracking technique. Based on this technique, a feature region of a human, for example, is extracted from an image signal acquired from a light-measuring unit, and a correlated image is determined within subsequently acquired images. In this way, the extracted feature region can be focused and utilized for exposure control.
However, if it is attempted to increase the operable light-metering range based on the technique discussed in Japanese Patent Application Laid-Open No. 6-130462, with the technique of tracking an object based on light-metering data supplied from a light-metering unit as in the imaging apparatus discussed in Japanese Patent Application Laid-Open No. 7-110429, the following problems occur.
If a light-metering operation using a prolonged charge accumulation time and a light-metering operation using a shortened charge accumulation time are alternately executed to increase the operable light-metering range, each of the luminance ranges in which a light-metering operation is possible is different from each other. Thus, even if the luminance of a target tracking region is within the operable light-metering range in one light-metering operation, the luminance may be outside the operable light-metering range in another light-metering operation. If calculation is executed for correlation between such two light-metering data to track an object, accuracy of the correlation calculation is decreased. As a result, the object cannot be tracked or accuracy in tracking the object is decreased.
Similarly, if the imaging apparatus discussed in Japanese Patent Application Laid-Open No. 2011-35765 alternately executes a light-metering operation using a prolonged charge accumulation time and a light-metering operation using a shortened charge accumulation time, a feature region may or may not be extracted. Thus, a feature region cannot be stably extracted.

Imaging apparatus and exposure control method


The present invention provides a shaping guide to permit accurate shaping of the tibial plateau while saving the anterior cruciate ligament. An alignment rod is located anterior to the anterior cruciate ligament and along the anterior cortex of the intermedullary canal of the tibia provides points of reference for all shaping operations. The shaping guide of the present invention is adjustable with respect to the handle portion of the rod so that the amount of resection of the tibial plateau can be controlled readily by the surgeon by raising or lowering of the cutting guide surfaces for resection of the tibia.

This invention relates to a method and apparatus for shaping the proximal surface of a human tibia, employing a novel adjustable shaping guide, which enables resection to be accomplished without sacrifice of the anterior cruciate ligament.
In replacing a knee joint which has been damaged due to disease or trauma, it is very important that the prosthesis used to replace the damaged portion of the joint be properly aligned with respect to the bone to which the prosthesis is fixed. Particular problems are encountered when resection of the proximal surface of the tibia is required, in that most shaping instrumentation requires sacrifice of the anterior cruciate whereas in most replacements the stability of the knee with replacement implants in place would be significantly improved by retaining the ligament.
To enable a surgeon to shape the proximal tibia to receive a tibial component of a total knee joint prosthesis, Leo A. Whiteside, one of the named inventors herein, developed a method and apparatus for shaping a proximal tibial surface which is claimed in U.S. Pat. No. 4,467,801. That patent teaches the use of an intramedullary alignment guide which provides the surgeon with a means for determining the central long axis of the tibia and a means by which the surgeon can shape the proximal tibia relative to that axis by attaching a planer or similar shaping instrument to that alignment guide. The anterior cruciate ligament is generally sacrificed using that method and apparatus.

Tibial surface shaping guide for knee implants


A method of inspecting articles using an imaging inspection apparatus which utilizes a plurality of individual imaging devices for directing beams onto the articles having objects therein to detect the objects based on established criteria. The method involves the enhanced cooling of the heat-generating imaging devices in which a fan directs cooling fluid onto a plurality of deflectors which in turn direct said fluid onto selected ones of said imaging devices.

The use of imaging inspection apparatus of the above type is known, including those which utilize X-ray imaging. Such apparatus are used to inspect articles such as personal luggage of airplane travelers at airports for such undesirable items as explosives and drugs. One particularly successful example of such apparatus is that which utilizes what is referred to in the art as "X-ray Computer Tomography" (hereinafter also referred to as, simply, XCT). XCT apparatus are in wide use in the medical field for providing medical imaging such as patient body X-rays. XCT (often referred to in the medical profession simply as "CT scanning") produces a cross sectional image from a grouping of attenuation measurements taken at different angles about an object such as a patient's chest or head, while the patient is maintained in a stationary position.
Some versions of the above apparatus have been modified to be more adaptable to taking images for non-medical purposes. In U.S. Pat. No. 5,367,552, issued Nov. 22, 1994, for example, a rotating XCT scanning unit is used which requires an object to remain stationary during scanning. This apparatus is designed for detecting concealed objects, such as explosives, drugs, or other contraband in a person's luggage. The apparatus uses scanning to identify concealed objects with a density corresponding to the density of target objects such as explosives or drugs. To reduce the amount of scanning required, a number of pre-scanning approaches are described in this patent. Based upon pre-scan data, selected locations for scanning are identified. The resulting scan data is utilized to automatically identify objects of interest, which identification is further verified through automatic analysis of such attributes as shape, texture, context, and X-ray diffraction. The objects of interest are then reconstructed and displayed on a computer monitor for visual analysis by the apparatus operator.
High speed scanning, such as that useful for scanning luggage of large numbers of travelers in a relatively shorter time period than provided by conventional stationary apparatus, requires that even further modifications be made. One such apparatus is described in U.S. Pat. No. 6,236,709, issued May 22, 2001, in which a continuous, XCT imaging system includes a conveyor which moves a closed package for being scanned along the conveyor past three spaced sensing stations. At each sensing station a plurality of X-ray sources each emit a fan beam in the same scan plane which passes through the package to a plurality of detectors opposite the X-ray sources. One scan is a vertical perpendicular scan plane relative to the direction of travel of the package along the conveyor belt and the remaining two scan planes are horizontal scan planes at right angles and transverse to the direction of travel. One horizontal scan plane is a left to right scan plane while the remaining scan plane is a right to left scan plane. Each detector provides multiple energy outputs for the same data point in a scan slice, and the detector outputs are stored until all three sensing stations have scanned the same cross sectional view of the package in three directions. Scans are sequentially taken as the package moves continuously through the sensing stations and scanned data corresponding to cross sectional views of the package is accumulated. The stored data is calibrated and normalized and then used in a Computer Tomographic algebraic reconstruction technique. This is described in this patent as a "multi-spectral CT reconstruction", where the density of a reconstructed object is determined by the attenuation which it causes in the scanning X-rays while the atomic number of the object is determined from the multiple energy scan output. In a classifier, the density and atomic number are compared to a table containing density and atomic number identification values for specific objects to be located.
Accurate, rapid inspection of moving articles such as multiple luggage pieces, often having many different sizes and shapes, is, understandably, a relatively difficult task, as indicated by just some of the difficulties mentioned in some of the patents cited herein and elsewhere in the literature pertaining to this art with respect to articles in both stationary and moving positions. When utilizing many heat-generating devices such as X-ray sources, it is essential that these sources operate at the proper temperature. Otherwise, the devices may be subject to failure, which is costly in both replacement terms as well as apparatus shutdown. Maintaining these heat-generating devices at proper temperature is thus critical to assuring effective apparatus operation.
Attention is directed to the following U.S. Patents which describe various types of scanning apparatus (in addition to those cited in the patents above), some of which utilize some form of means to provide cooling for the apparatus.
In U.S. Pat. No. 6,778,635, issued Aug. 17, 2004, there is described an x-ray tube cooling system which utilizes a heat sink partially disposed within an evacuated housing of the x-ray tube and having a cooling block partially received within the bearing housing to absorb heat transmitted to the bearing assembly and bearing housing. Extended surfaces are disposed in a coolant chamber defined by the cooling block and a shell within which the cooling block is partially received. The shell defines a coolant chamber entrance and coolant chamber exit in fluid communication with the coolant chamber. The coolant chamber entrance and exit communicate with corresponding coolant inlet and outlet passageways, respectively, cooperatively defined by a pair of insulators which retain the heat sink in a predetermined orientation within an evacuated envelope of an x-ray device. A circulating coolant contacts the extended surfaces and thereby removes heat from various structures of the x-ray device.
In U.S. Pat. No. 6,714,626, issued Mar. 30, 2004, there is described an x-ray tube cooling assembly which includes an electron collector body coupled to an x-ray tube window and having a first coolant circuit. The coolant circuit includes a coolant inlet and a coolant outlet. The coolant outlet directs coolant at an x-ray tube window surface to impinge upon and cool the x-ray tube window. The coolant is reflected off the reflection surface to impinge upon and cool the x-ray tube window.
In U.S. Pat. No. 6,709,156, issued Mar. 23, 2004, there is described a cooling device for an X-ray source that is arranged in a gantry around a rotational axis. The device includes a ring-like heat exchanger that is positioned at the gantry and is thermally connected to the X-ray source. The cooling device is useable in a computed tomography apparatus having the X-ray source.
In U.S. Pat. No. 6,669,366, issued Dec. 30, 2003, there is described an X-ray examination apparatus in which the X-ray detector and the X-ray source are subject to keeping the temperature constant and to cooling by way of a common cooling "circuit". A cooling medium of constant temperature is applied to the X-ray detector in order to make the detector operate at desired temperatures. The temperature of the cooling medium, increased a first time, allegedly performs cooling of the X-ray source. The heated cooling medium, after application to the X-ray detector, is applied to the X-ray source where a second exchange of heat takes place, so the X-ray source is cooled without utilizing an additional cooling circuit.
In U.S. Pat. No. 6,619,841, issued Sep. 16, 2003, there is described a fluid-cooled X-ray tube which includes a closed coolant "circuit" in which coolant circulates for the elimination of generated heat. In order to improve the cooling capacity, micro-capsules containing a phase-change material (PCM) are added to the coolant. In this arrangement, heat arising from the X-ray tube is intermediately stored in the PCM storage elements for a certain time span. Dependent on the selected material of the PCM and the amount of the PCM storage elements introduced into the coolant, the temperature of the coolant can be kept nearly constant over a specific time segment despite the heat arising from the tube during X-ray generation. Compared to conventional measures for cooling an X-ray tube, this patent mentions that the rise in temperature of the coolant is retarded by this arrangement, so that the X-ray radiator can be more highly stressed (loaded) over the same operating duration, or the operating duration of the X-radiator can be significantly lengthened given the same load. Described PCM materials for this purpose are paraffins whose melting temperatures lie between ninety and one hundred and twelve degrees Celsius. Mentioned alternatives to paraffin include fatty alcohols, fatty acids, hydrates of sodium carbonate, sodium acetate, calcium chloride and lithium magnesium nitrate.
In U.S. Pat. No. 6,529,579, issued Mar. 4, 2003, there is described a cooling system for high-powered X-ray tubes. The cooling system includes a reservoir containing liquid coolant, in which the high-powered X-ray tube is partially immersed. In general, the liquid coolant is cooled and then circulated through the reservoir by an external cooling unit. The cooling system also includes a shield structure attached to the vacuum enclosure of the X-ray tube and disposed substantially about the aperture portion of the vacuum enclosure, thereby defining a flow passage proximate the aperture portion. Liquid coolant supplied by the external cooling unit enters the flow passage by way of an inlet port in the shield structure. After passing through the flow passage and transferring heat out of the aperture portion, the liquid coolant is discharged through an outlet port in the shield structure and enters the reservoir to repeat the cycle.
In U.S. Pat. No. 6,496,564, issued Dec. 17, 2002, there is described an X-ray system with an X-ray "generating device" which includes an X-ray tube mounted in a casing holding a circulating, cooling medium. According to the description, the X-ray generating device includes a support mechanism mounted within the X-ray generating device in a manner for adjustably positioning, relative to the casing, the focal spot alignment path of generated X-rays. Additionally, the device includes a cooling mechanism having an inlet chamber for channeling the cooling medium within the support mechanism. Still further, a cooling stem may be positioned within the inlet chamber to increase the heat exchange surface area exposed to the cooling medium.
In U.S. Pat. No. 6,400,799, issued Jun. 4, 2002, there is described an x-ray tube cooling system which utilizes a shield structure connected between a cathode cylinder and an x-ray tube housing and disposed between the electron source and the target anode. The system uses a plurality of cooling fins to improve overall cooling of the x-ray tube and the shield so as to extend the life of the x-ray tube and related components. When immersed in a reservoir of coolant fluid, the fins facilitate improved heat transfer by convection from the shield to the to the coolant fluid. The cooling effect achieved with the cooling fins is further augmented by a convective cooling system provided by a plurality of passageways formed within the shield, which are used to provide a fluid path to the coolant. In particular, a cooling unit takes fluid from the reservoir, cools the fluid, and then circulates the cooled fluid through cooling passages. The coolant is then output from the passageway and directed over the cooling fins. In some embodiments, the passageways are oriented so as to provide a greater heat transfer rate in certain sections of the shield than in other sections.
U.S. Pat. No. 6,052,433, issued Apr. 18, 2000, describes an apparatus for performing dual-energy X-ray imaging using two-dimensional detectors. The apparatus consists of an X-ray source, a 2-dimensional X-ray detector, a beam selector, and a second 2-dimensional X-ray detector. The subject is located between the X-ray source and first detector. The beam selector prevents primary X-rays from reaching selected locations of the second (rear) detector. A pair of primary dual-energy images is obtained at the rear detector. Using a dual-energy data decomposition method, a low-resolution primary X-ray first detector image is calculated, from which a high-resolution primary dual-energy image pair is calculated. In addition, the data decomposition method is used to calculate a pair of high-spatial-resolution material composition images.
U.S. Pat. No. 6,018,562, issued Jan. 25, 2000, describes an apparatus for automatic recognition and identification of concealed objects and features thereof, such as contraband in baggage or defects in articles of manufacture. The apparatus uses multiple energy X-ray scanning to identify targets having a spectral response corresponding to a known response of targets of interest. Detection sensitivity for both automatic detection and manual inspection are improved through the multiple-energy, multi-spectral technique. Multi-channel processing is used to achieve high throughput capability. Target identification may be verified through further analysis of such attributes as shape, texture, and context of the scan data. The apparatus uses a statistical analysis to predict the confidence level of a particular target identification. A radiograph, CT image, or both may be reconstructed and displayed on a computer monitor for visual analysis by the apparatus operator. Finally, the apparatus may receive and store input from the operator for use in subsequent target identification.
U.S. Pat. No. 5,991,358, issued Nov. 23, 1999, describes a data acquisition system for use in a CT scanner which consists of an analog-to-digital converter for generating digital signals in response to analog signals representative of projection data taken at a relatively constant sampling rate. The apparatus also uses an interpolation filter for generating projection data for a plurality of predetermined projection angles as a function of the digital signals irrespective of the sampling rate. This patent references a known system which includes an array of individual detectors disposed as a single row in the shape of an arc of a circle having a center of curvature at a certain point, referred to as the "focal spot", where the radiation emanates from the X-ray source. The X-ray source and the array of detectors in this known system are positioned so that the X-ray paths between the source and each of the detectors all lie in the same plane (hereinafter the "rotation plane" or "scanning plane") which is normal to the rotation axis of the disk. Since the X-ray paths originate from what is substantially a point source and extend at different angles to the detectors, the X-ray paths form a "fan beam." The X-rays incident on a single detector at a measuring interval during a scan are commonly referred to as a "ray", and each detector generates an analog output signal indicative of the intensity of its corresponding ray. Since each ray is partially attenuated by all the mass in its path, the analog output signal generated by each detector is representative of an integral of the density of all the mass disposed between that detector and the X-ray source (i.e., the density of the mass lying in the detector's corresponding ray path) for that measuring interval.
U.S. Pat. No. 5,629,966, issued May 13, 1997, describes a real time radiographic test system which consists of a protective housing and a conveyor for conveying articles to be tested through the housing. A real time radiographic test instrument is located in the housing for performing a real time radiographic test on the article. The test instrument includes X-ray equipment disposed for directing an X-ray beam within the housing in a direction which does not intersect the conveyor. An article-handling actuator is located in the housing for repositioning an article from the conveyor to a position in registry with the X-ray beam, for maintaining the article in registry with the X-ray beam while the real time radiographic test is performed on the article and thereafter returning the article to the conveyor. The article-handling actuator and the X-ray equipment are designed such that each article to be tested is positioned substantially identically relative to the X-ray beam.
U.S. Pat. No. 5,583,904, issued Dec. 10, 1996, describes a laminographic system that allows generation of high speed and high resolution X-ray laminographs by using a continuous scan method with two or more linear detectors and one or more collimated X-ray sources. Discrete X-ray images, with different viewing angles, are generated by each detector. The discrete X-ray images are then combined by a computer to generate laminographic images of different planes in the object under test, or analyzed in such a manner to derive useful data about the object under test. This system does not require any motion of the source or detectors, but simply a coordinated linear motion of the object under test. Higher speed is achieved over conventional laminography systems due to the continuous nature of the scan, and due to the ability to generate any plane of data in the object under test without having to re-image the object.
U.S. Pat. No. 5,524,133, issued Jun. 24, 1996, describes an X-ray analysis device for determining the mean atomic number of a material mass by locating a broad band X-ray source on one side of a testing station and on the other, a detector, comprising a target having X-ray detectors positioned adjacent thereto. One of the detectors is positioned and adapted to receive X-rays scattered by the detector target in a generally rearward direction and the other detector is positioned and adapted to detect forwardly propagating X-rays scattered off axis typically by more than thirty degrees, due to so-called "Compton scatter." Each of the X-ray detectors provides signals proportional to the number of X-ray photons incident thereon. The apparatus further includes means responsive to the two detector outputs which form a ratio of the number of photons detected by the two detectors and forms a numerical value thereof. A look-up table containing mean atomic numbers for given numerical ratios for different materials is used, as is a means for determining from the look-up table the atomic number corresponding to the numerical ratio obtained from the outputs of the two detectors. The atomic number is provided as an output signal.
U.S. Pat. No. 5,483,569, issued Jan. 9, 1996, describes an inspection system for inspecting objects with "penetrating radiation" having a conveyor with first and second portions which are separated by a gap. Illumination by this radiation is provided in a scanning plane which is located in the gap, and the system may be used for the inspection of thin objects. Additionally, the illumination may be arranged in the inspection of normal size objects, e.g., suitcases or cargo boxes, so that it does not include a ray which is perpendicular to any face of the object. Further, the relative orientation of the scanning plane and the faces of the object may be arranged so that the illumination does not include a ray which is parallel to any face of the object. A scanning configuration wherein the illumination does not include a ray which is perpendicular or parallel to any face of an object having parallel faces, for example, a rectangular solid, results in a display projection of the object which appears to be three dimensional.
U.S. Pat. No. 5,259,012, issued Nov. 2, 1993, describes a system which enables multiple locations within an object to be imaged without mechanical movement of the object. The object is interposed between a rotating X-ray source and a synchronized rotating detector. A focal plane within the object is imaged onto the detector so that a cross-sectional image of the object is produced. The X-ray source is produced by deflecting an electron beam onto a target anode. The target anode emits X-ray radiation where the electrons are incident upon the target. The electron beam is produced by an electron gun which includes X and Y deflection coils for deflecting the electron beam in the X and Y directions. Deflection voltage signals are applied to the X and Y deflection coils, and cause the X-ray source to rotate in a circular trace path. An additional DC voltage applied to the X or Y deflection coil will cause the circular path traced by the X-ray source to shift in the X or Y direction by a distance proportional to the magnitude of the DC voltage. This causes a different field of view, which is displaced in the X or Y direction from the previously imaged region, to be imaged. Changes in the radius of the X-ray source path result in a change in the Z level of the imaged focal plane.
U.S. Pat. No. 5,026,983, issued Jun. 25, 1991, describes an apparatus for examining food products for undesired ingredients by means of laser irradiation. A laser beam scans the food products according to a predetermined pattern. Variations in the intensity of the laser beam passing through the food products indicate the presence of undesired ingredients. This method is carried out by an apparatus which comprises two parabolic mirrors, a laser emitting a laser beam so as to originate from the focus of one of the mirrors and a detection means positioned in the focus of the other mirror. The food products are moved between the mirrors by conveyor belts.
U.S. Pat. No. 5,020,086, issued May 28, 1991, describes a situation where an object is scanned by an X-ray beam from a circular position on a target resulting from the electron beam being scanned in a circle by appropriate control signals from a beam controller and applied to the deflection coils of a microfocus X-ray tube. Tomosynthesis is accomplished by the well-known method of in-register combination of a series of digital X-ray images produced by X-ray beams emanating from different locations. This is achieved by positioning an X-ray source at multiple points on a circle around a central axis. This system eliminates some mechanical motion in that the detector does not have to rotate. However, practical limitations of pixel size and resolution tend to limit this system to inspection of items with small fields of view. Additionally, the system still requires an X, Y table to position the object under the field of view.
The above patents and co-pending applications are incorporated herein by reference.
The present invention defines a new and unique inspection method which assures that effective cooling of the scanning devices is assured. Such cooling is accomplished for a number of scanning devices in a new and unique manner representing a significant improvement over cooling methods for apparatus such as described above. It is believed that such a method would constitute a significant advancement in the art.

This patent is subject to a terminal disclaimer.

Method of inspecting articles using imaging inspection apparatus with directional cooling

Endicott Interconnect Technologies, Inc.


Embodiments relate to providing trusted tokenized transactions in a blockchain system. In one embodiment, a tokenization request may include identification information. A fiduciary server may apply a cryptographic private key to a hash of the identification information to generate a digital signature. An exchange server may cause a transmission of the digital signature to a blockchain. The blockchain includes a set of code instructions that verify the digital signature. The verification may include applying the public key corresponding to the cryptographic private key to decrypt the digital signature to re-generate the hash of the identification information. The hash may ensure the integrity of the identification information. The code instructions recorded on the blockchain, when executed, cause a computer to generate a blockchain unit. The tokenized transactions are traceable to the digital signature of the fiduciary server. This may provide a trusted transaction for users of the blockchain regarding the tokenized transactions.

A blockchain may include a chain of data blocks that are linked together through hashes of previous blocks. The transactions stored in an intermediate block is often immutable. Various participants in the blockchain may independently verify the validity of a transaction by tracing through the history of the chain of transactions. In a public blockchain, different parties may independently verify the blocks recorded on the chain so that it becomes very challenging for a single party to manipulate or forge a transaction stored in a block. A blockchain often provides greater transparency, enhanced security, and improved traceability than a centralized system.
Through a blockchain system, a wide variety of blockchain units such as tokens that can be exchanged through the distributed ledger system of the blockchain may be generated. The generation of a blockchain unit may depend on the conditions that are initially set by the issuer of the blockchain unit. While participants of a blockchain may verify the validity of individual transactions, the initial generation of the blockchain units may be subject to various conditions that are not necessarily trusted.

Trusted tokenized transactions in a blockchain system


A coconut shredding/grating apparatus for allowing a user to shred and grate a coconut. The coconut shredding/grating apparatus includes a base member including main base portion having top and bottom sides; and also includes a housing being mounted upon the top side of the base member and having front, rear and side walls, and also having a hole being disposed through the front wall; and further includes a coconut shredding assembly including a motor being disposed in the housing and having a motor shaft, and also including a control assembly for energizing and operating the motor, and further including a coconut shredding member being detachably connected to the motor shaft for rotation therewith; and also includes a coconut support assembly including a coconut support member being removably secured upon the base member; and further includes a tray being removably disposed upon the base member for receiving shredded and grated coconut.

1. Field of the Invention
The present invention relates to coconut shredders and graters and more particularly pertains to a new coconut shredding/grating apparatus for allowing a user to shred and grate a coconut.
2. Description of the Prior Art
The use of coconut shredders and graters is known in the prior art. More specifically, coconut shredders and graters heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. No. 4,350,088; U.S. Pat. No. 4,708,056; U.S. Pat. No. 4,383,479; U.S. Pat. No. 5,267,698; U.S. Pat. No. 1,554,516; and U.S. Pat. No. Des. 335,615.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new coconut shredding/grating apparatus. The prior art includes housings with the coconuts being placed upon spits and rotated into stationary blades.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new coconut shredding/grating apparatus which has many of the advantages of the coconut shredders and graters mentioned heretofore and many novel features that result in a new coconut shredding/grating apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art coconut shredders and graters, either alone or in any combination thereof. The present invention includes a base member including main base portion having top and bottom sides; and also includes a housing being mounted upon the top side of the base member and having front, rear and side walls, and also having a hole being disposed through the front wall; and further includes a coconut shredding assembly including a motor being disposed in the housing and having a motor shaft, and also including a control assembly for energizing and operating the motor, and further including a coconut shredding member being detachably connected to the motor shaft for rotation therewith; and also includes a coconut support assembly including a coconut support member being removably secured upon the base member; and further includes a tray being removably disposed upon the base member for receiving shredded and grated coconut. None of the prior art includes the combination of the elements of the present invention.
There has thus been outlined, rather broadly, the more important features of the coconut shredding/grating apparatus in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and; should not be regarded as limiting.
It is an object of the present invention to provide a new coconut shredding/grating apparatus which has many of the advantages of the coconut shredders and graters mentioned heretofore and many novel features that result in a new coconut shredding/grating apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art coconut shredders and graters, either alone or in any combination thereof.
Still another object of the present invention is to provide a new coconut shredding/grating apparatus for allowing a user to shred and grate a coconut.
Still yet another object of the present invention is to provide a new coconut shredding/grating apparatus that is easy and convenient to set up and use.
Even still another object of the present invention is to provide a new coconut shredding/grating apparatus that is more safe than hand-held shredders and also saves the user substantial time in shredding and grating coconut.


A computerized method and system of segment-based video encoding optimization, the method comprising obtaining a set of input segments constituting an input video stream; selecting one or more input segments in accordance with a selection criterion to be one or more representative segments; determining an encoding instruction and obtaining one or more encoded representative segments encoded from the representative segments in accordance with the encoding instruction and using a quality-driven video encoding scheme; determining, based on the encoded representative segments, an encoding configuration, and obtaining one or more encoded input segments encoded from at least a sub-set of the input segments using the encoding configuration; determining an evaluation instruction used to evaluate quality for each encoded input segment; and generating an output video stream, by selecting, for each input segment, a corresponding output segment from a group comprising at least one of the following candidate segments: the input segment, an encoded representative segment, and an encoded input segment.

Nowadays, with the fast development of imaging and video technologies, video plays a key role as a mechanism of information exchange, transmission or storage. Video encoding has been deployed in many applications and equipment, ranging from digital cinema, mobile handsets, cable and satellite digital video transmissions, to machine vision and recognition systems, etc. With the proliferation of viewing platforms, file formats and streaming technologies competing in today's online media ecosystem, video encoding is becoming increasingly complicated and cumbersome. Optimal encoding and re-encoding of video content, such as, e.g., video compression and recompression, remains as a longstanding challenge in the field.
Given a particular video encoder, the goal of video encoding is often to create an encoded video which has maximal quality and best user experience, given a set of limited resources such as total bandwidth, computation power etc. Some of the currently available video encoders may focus on encoding at a certain bit-rate without considering the encoded video quality, whereas some others may target at achieving a given quality criterion while neglecting time and bit consumption of such encoding. It is widely acknowledged that a large part of the challenge consists in reliably and automatically determining the subjective quality of a candidate video clip, or of being able to obtain minimal bit-rate for a desired target quality, on a per clip or per title basis. It is challenging and complex to provide an optimal video encoding solution that is both efficient and cost-effective.

Method and system of video encoding optimization


An antenna assembly includes a bobbin positionable about an outer surface of a tool mandrel and providing an outer bobbin surface. A coil is wrapped about and extends longitudinally along at least a portion of the outer bobbin surface. An inner sleeve interposes the bobbin and the tool mandrel and receives a plurality of ferrites that interpose the tool mandrel and the coil.

During drilling operations for the extraction of hydrocarbons, a variety of recording and transmission techniques are used to provide or record real-time data from the vicinity of a drill bit. Measurements of the surrounding subterranean formations may be made throughout drilling operations using downhole measurement and logging tools, such as measurement-while-drilling (MWD) and/or logging-while-drilling (LWD) tools, which help characterize the formations and aid in making operational decisions. Wellbore logging tools make measurements that may be used to determine the electrical resistivity (or its inverse, conductivity) of the formations being penetrated, where the electrical resistivity indicates various features of the formations. Those measurements may be taken using one or more antennas coupled to or otherwise associated with the wellbore logging tools.
Logging tool antennas are often formed by positioning coil windings about an axial section of the logging tool, such as a drill collar. A ferrite material or "ferrites" are sometimes positioned beneath the coil windings to increase the efficiency and/or sensitivity of the antenna. The ferrites facilitate a higher magnetic permeability path (i.e., a flux conduit) for the magnetic field generated by the coil windings, and help shield the coil windings from the drill collar and associated losses (e.g., eddy currents generated on the drill collar).

Antenna assembly using ferrites within an interposed sleeve for wellbore logging tools


Identification and extraction of hybrid, frequency-hopped direct sequence pseudo noise (FH/DS), signals from a multiband signal environment is effected by a sequential signal processing technique which examines the distribution of the energy content within a prescribed sub-spectrum window that is iteratively scanned or `slides` across the overall signal spectrum of interest. Based upon this energy content distribution, in particular the extent to which a sub-spectrum window contains energy that exhibits significant conjugate phase symmetry associated with a direct spread signal, the inventive signal processing technique proceeds to emphasize the spectral composition of components of which hybrid signals are comprised and to deemphasize the spectral composition of signals other than those contained in hybrid signals. Potential hybrid signal candidates whose spectral composition has been emphasized are then selectively combined with the deemphasized signals to isolate and identify the hybrid signals.

Because of their low probability of intercept and resistance to jamming, direct sequence pseudo noise (DSPN) and frequency hopping techniques are often used to successfully conduct secure/covert communications. For increased immunity against interception, these two techniques may be combined to produce hybrid spread spectrum (HSS) signals, i.e. those which employ a combination of frequency hopping (FH) and DSPN modulation. Unfortunately, each of these two modulation techniques customarily employs its own signal processing mechanism, that does not readily lend itself to recovery of the other form of modulation, particularly in a multi-signal type environment which may contain a variety of narrowband signals, such as AM, FM, PSK, and narrowband frequency hopping signals, all occurring simultaneously within the same operating frequency spectrum.
More particularly, a conventional mechanism utilized for (narrowband, positive signal-to-noise ratio) frequency hop detection is the channelized radiometer, containing a filter bank to isolate each of the frequencies to which the FH source may hop, with each filter being tuned to a respectively different instantaneous bandwidth or channel. Interception of a (wideband, negative signal-to-noise ratio) DSPN signal, on the other hand, normally entails the use of non-linear signal processing, such as squaring or convolution, in order to collapse the wideband spectrum down to a readily identifiable spectral line. Because of the low concentrated energy content (negative S/N) of the spread signal, the integration time required to process detected energy can be expected to be considerably longer than a frequency hop dwell time, so that recovery of an HSS signal may not be successful using conventional spread spectrum processing. Of course, complicating the problem is the fact that the signal environment being monitored for the presence of hybrid signals is not particularly `clean`. It can be expected to be cluttered with a large number of signals having a variety of modulation formats, which effectively mask the presence of hybrid signals.

Mechanism for extracting hybrid (fh/ds) spread spectrum signals within multi-signal type environment


A method of improving high-current density efficiency of an LED, said method comprising: (a) preparing a series of LEDs having decreasing defect densities, wherein each LED of said series has a peak IQE of at least 50%, and wherein each LED of said series has the same epitaxial structure; (b) determining an increase in IQEs at high-current density between at least two LEDs of said series; (c) preparing at least an additional LED of said series by reducing defect density relative to the previously obtained lowest defect density; and (d) reiterating steps (b) and (c) until said increase is at least 3% between two LEDs of said series having a decrease X in defect densities.

Certain applications require III-Nitride LEDs to be efficient at high current density. This is challenging because of the phenomenon of efficiency droop, whereby the internal quantum efficiency (IQE) of a III-Nitride LED decreases at high current density.
By way of background, IQE is understood conventionally as a competition between three effects: (1) low-current nonradiative recombinations, (2) radiative recombinations, and (3) high-current nonradiative recombinations. Low-current nonradiative recombinations are widely understood to be induced by defects in the crystal, and to be a type of Shockley-Read-Hall (SRH) recombination. If n and p are the densities of electrons and holes in the active region, they can be expressed as G_SRH=2 Anp/(n+p). In the typical case where n=p, this is equivalent to G_SRH=An. Radiative recombinations involve an electron and a hole, and can be expressed as G_Rad=Bnp=Bn{circumflex over ( )}2 (when n=p). High-current non-radiative recombinations are widely believed to be caused by Auger scattering, which can be expressed as G_droop=(c1 n{circumflex over ( )}2p+c2 np{circumflex over ( )}2)=C n{circumflex over ( )}3. While others have proposed alternative models, in all embodiments, the droop current effectively scales with a high power of the carrier density (often with an exponent of 3, or more).
The IQE can be expressed as a combination of these different recombinations, i.e. IQE=Bn{circumflex over ( )}2/(An+Bn{circumflex over ( )}2+Cn{circumflex over ( )}3). This is the well-known "ABC model." Often, coefficients A B and C are empirical and are chosen to match experimental data. The value of A, in particular, scales with the concentration of point defects. This modeling results in the well-known bell-shaped efficiency curve shown on FIG. 1. Although DAVID ET AL., All-optical measurements of carrier dynamics in bulk-GaN LEDs: Beyond the ABC approximation, Appl. Phys. Lett. 110, 253504 (2017) (David17) refines this model to better match experimental data, the model shares the same basic features—i.e., at low current, G_SRH dominates, at intermediate currents G_Rad dominates, and finally, at high current, G_droop dominates.
It is important to note that, in these proposed models, the nonradiative recombinations at low- and high-current density (respectively G_SRH and G_droop) are understood to be caused by distinct and unrelated physical phenomena. Low-current recombinations are caused by defects in the crystal (i.e. an extrinsic process), while high-current recombinations are caused by phenomena unrelated to defects (i.e., an intrinsic process). Accordingly, reducing G_SRH is believed to be a distinct challenge from reducing G_droop.
The independence of G_SRH and G_droop can be quantified numerically using the equations mentioned above. FIG. 2A shows modeled IQE using a basic ABC model for various values of A. The parameters are as follows: B=1.6e-13 cm3 s-1, C=3.16e-33 cm6 s-1, and A varies between 1E3 and 1E6 s-1. The values of B and C are representative of a 4 nm InGaN single quantum well (QW) with 13% In concentration. As A increases, the low-current efficiency and the peak efficiency decrease. However, the difference vanishes at high current density. For instance, at J=100 A·cm-2, all curves have the same IQE within +/−1% absolute—a very small variation. FIG. 2B further exemplifies the relative variation of IQE as a function of the relative defect density at 100 A·cm-2. Here, the baseline for relative comparison corresponds to the case A=1E6 s-1. When A is reduced tenfold, the relative IQE increases by less than 2%.
Although A could be high enough (for instance A=1E7) such that the high-current efficiency at 100 A·cm-2 would start to be impacted because SRH recombinations would become strong enough to be significant, this would correspond to a low-quality crystal having a low peak IQE (e.g. 30% for A=1E7). But for technologically-relevant devices, IQE>50% is desirable. Accordingly, the disclosure herein relates to the regime of sufficiently-good devices having sufficient crystal quality, where the effect of SRH recombinations is very small at high current density. In such crystals, the conventional understanding of IQE provides no motivation to improve high-current IQE by reducing point defects. This may correspond to LEDs having a peak IQE above 50% (or above 60%, 70%, 80%).
This understanding also applies to more sophisticated versions of the ABC model. For instance, [David17] showed that screening effects should be included in B and C (as will be further detailed later in this Application)—namely B and C are not strictly constant, but have a current dependence caused by screening. Including these screening effects slightly modifies the ABC model. For this improved ABC model, the influence of A on IQE is shown on FIG. 3. Screening effects change the high-efficiency shape of the IQE curve. However, even with an understanding of screening effects, the conventional belief that the effect of A on high-current IQE is very small remains.
This conventional belief also applies to different LED designs. For instance, increasing the In concentration can lead to lower values of A, B and C (which roughly scale together)—but the relative effect of A at high current density remains very small. Likewise, droop onset can be delayed by using thick active regions with more quantum wells. Here again however, SRH recombinations are believed to have little effect in the droop regime.
In summary, it is widely believed that the nonradiative recombinations at low-current density and high-current density are caused by distinct and unrelated physical phenomena—namely, low-current recombinations are caused by defects in the crystal (extrinsic process), whereas high-current recombinations are caused by phenomena unrelated to defects (intrinsic process). Thus, according to the conventional understanding, for a sufficiently good LED, a large variation in defect density translates into a very small improvement in high-current-density IQE. For example, a substantial 10× reduction in defect density causes less than 2% absolute (or 5% relative) increase in IQE at 100 A·cm-2. Accordingly, efforts to improve the efficiency of a III-Nitride LEDs at high current density and avoid current droop have been focused on other strategies, such as increasing the thickness of the active region and improving the carrier spreading across the active region. These approaches have been met with limited success. Therefore, the need to improve the efficiency of a III-Nitride LEDs at high current density remains. The present invention fulfills this need, among others.

High efficiency group-III nitride light emitting diode


An electronic lock controller comprises a trusted time provider, a near field communication transceiver, and a logic processor. The trusted time provider provides a trusted time value. The near field communication transceiver receives power and a digital credential from an operator-side interface device. The logic processor produces an open or close command for an electromechanical lock based on the trusted time value and the digital credential. The electronic lock controller is powered solely by the near field communication transceiver.

The present invention relates generally to wireless electromechanical locks, and more particularly to batteryless timekeeping for wireless electromechanical locks.
Electromechanical locks use a combination of electronic and mechanical components, typically including an electronic controller, a mechanical locking mechanism, and an electronic actuator capable of switching mechanical components between locked and unlocked states. Mechanical locking mechanisms may comprise, for instance, mechanical bolts and strikes. Some electronic actuators entirely open and close locks, such as by shifting a bolt. Other electronic actuators only release pins or catches so that an operator may open the lock. In either case, electronic actuators are controlled by electronic controllers, which respond to user inputs such as RFID information, passkeys, or other digital certificates. Controllers process and authenticate user inputs, and command electronic actuators to open or close accordingly. Electromechanical locks are conventionally powered with batteries, or by wired connection to a power grid.
Some electromechanical locks incorporate timekeepers such as real time clocks, enabling authentication procedures to depend on time. Such a lock might be configured, for instance, to allow the bearer of a particular digital certificate access into a restricted area only at certain times of day, or on certain days of each month. It is essential for such purposes that the electromechanical lock controller be provided with a trusted time, and not rely on operator-supplied or otherwise unsecured time values for certification.
Some electromechanical locks utilize near field communication (NFC) to communicate wirelessly with an operator. An operator-side interface device can inductively power the electromechanical lock for the duration of certification, thus allowing the lock to dispense with batteries and wired grid connections, reducing maintenance requirements and simplifying installation. Because NFC locks only receive power during intermittent interaction with an operator-side NFC initiator, however, a conventional continuous timekeeper such as a continuously active real time clock cannot be used. As a result, the prior art does not support trusted timekeeping for batteryless locks.


An image processing device includes a first image enhancer and a second image enhancer. The first image enhancer receives first image data and generates first image enhancement information by analyzing the first image data. The second image enhancer receives second image data and generates second image enhancement information by analyzing the second image data. The first image enhancer converts the first image data into first enhanced image data based on the first image enhancement information and the second image enhancement information. The second image enhancer converts the second image data into second enhanced image data based on the first image enhancement information and the second image enhancement information.

1. Field
The present inventive concept relates to processing of image data to be displayed, and more particularly to an image processing device for providing enhanced image data for a plurality of display devices.
2. Description of the Related Art
Recently, various display devices such as plasma display panel (PDP) devices, liquid crystal display (LCD) devices, light emitting diode (LED) devices, etc. are widely used. A plurality of display devices may be used in a single system to provide various images. For example, images may be displayed in the plurality of display devices, respectively, or a single image may be divided into a plurality of images to be displayed in the plurality of display devices.


An exemplary electroencephalogram measurement system includes: a frequency analysis section for, analyzing a frequency power of the electroencephalogram signal of a user with respect to each set of a reference electrode and a measurement electrode; an insufficient electrode determination section for, through comparison of the analyzed frequency power against a first threshold value, distinguishing whether a state of attachment of each electrode is sufficient or not; and an insufficiency cause estimation section for determining the number of insufficient electrodes distinguished as insufficiently worn, determining a position at which each insufficient electrode is in contact with the user, and estimating a cause for the insufficient state of attachment of the insufficient electrode or electrodes that corresponds to the determined number of insufficient electrodes and position of each insufficient electrode by referring to insufficiency pattern data.

1. Technical Field
The present disclosure relates to a system for measuring an electroencephalogram of a user who wears on his or her head a housing having electrodes provided thereon. Specifically, the present disclosure relates to an electroencephalogram measurement system for determining states of attachment of electrodes, and estimating an insufficiency cause in accordance with the position of any insufficient electrode.
2. Description of the Related Art
Conventionally, as a method of measuring an electroencephalogram (Electroencephalogram: EEG), a method which records changes in the potentials of two points on the scalp (potentials of a reference electrode and an electrode for measurement) is known. An electroencephalogram is an electrical signal which is measured as a potential difference between the reference electrode and the electrode for measurement. An electroencephalogram is supposed to reflect encephalic activities (electrical activities of the cranial nerve cells), and more specifically, electrical activities of the cerebral cortex. As compared to other methods of measuring encephalic activities in noninvasive manners, the aforementioned method of measuring potential changes as an electroencephalogram has the advantages of high time resolution and easy measurement. At medical institutions, electroencephalogram measurement methods based on electrical potentials have conventionally been used for diagnosis of epilepsy, Alzheimer's disease, and the like. At research institutions, electroencephalogram measurement methods have been utilized as tools for basis research on the process of perception and cognizance, which is information processing in the human brain.
In order to measure an electroencephalogram, it is necessary to attach electrodes on the head. Therefore, a method of electrode attachment will be described. First, paste is applied on an electrode. The paste is a cream having a high electrical conductivity, serving to enhance the electrical conductivity between the skin and the electrode. A specialist (a third person) other than the user ensures that the electrode having the paste applied thereon is in tight contact with the scalp of the user. Conventionally, since the electrode and an electroencephalograph would be connected via a lead wire which permits high freedom, the third person would be able to attach the electrode at any arbitrary position on the head of the user. Moreover, in the case of taking multi-point measurements by utilizing a plurality of electrodes, there exists a method which employs an electrode cap having high contraction and expansion properties. Both methods allow the electrodes to be stably attached at predetermined positions on the head, without being affected by the head shape of the user. For the electrode attachment, about several minutes is required for each electrode, which is a relatively long time. However, the time required for electrode attachment has never been regarded as a problem because, in the past, this has all been in a preparatory procedure for diagnosis or basis research.
In recent years, the downsizing of electroencephalographs and increased accuracy of signal processing techniques are making it possible to develop electroencephalogram interfaces for inferring the psychological state of a user based on an electroencephalogram and inferring his or her intent of manipulation as to how they want to manipulate a device, or intent of selection as to which one of a plurality of options they want to select.
For example, as an electroencephalogram interface for use with a healthy user, Emanuel Donchin and two others, "The Mental Prosthesis: Assessing the Speed of a P300-Based Brain-Computer Interface", TRANSACTIONS ON REHABILITATION ENGINEERING 2000, Vol. 8, June 2000 discloses an electroencephalogram interface which infers an intent of selection of a user. Among event-related potentials of the electroencephalogram, the electroencephalogram interface of Donchin et al. uses a characteristic signal component called "P300" to distinguish an option that a user wishes to select. As used herein, an "event-related potential" refers to a transient potential fluctuation in the brain, which is a portion of the electroencephalogram and which occurs in temporal relationship with an external or internal event. Moreover, "P300" refers to an event-related potential component, in an electroencephalogram signal at 20 milliseconds to 400 milliseconds as reckoned from a given event, having a positive (plus direction) amplitude peak.
However, in such manners of use, which require lead wires or a special cap to be attached with the help of a specialist, it is difficult for a user in a daily-life environment to wear the electrodes by himself or herself, have their electroencephalogram measured, and have the resultant electroencephalogram used for an electroencephalogram interface or the like. Now, an example will be discussed where an electroencephalogram measurement apparatus (electrodes and an amplifier) is incorporated in a wearable device such as a head-mount display (Head-Mount-Display: HMD) or a headset as a housing for electroencephalogram measurement to measure an electroencephalogram. A housing such as an HMD or a headset, for example, has a high rigidity as compared to the aforementioned lead wires or electrode cap, and is easy to wear. Therefore, it is not difficult for the user himself or herself to, as soon as wearing the HMD or headset, position any electrode for electroencephalogram measurement that is incorporated in the housing so as to be in the neighborhood where measurement is expected to be taken.
In the aforementioned conventional technique, the user himself or herself needs to apply paste on the electrodes. Furthermore, after the device is detached, the paste remaining on the electrodes and in the places where the electrodes have been disposed must be wiped off by the user himself or herself. Therefore, in order for the user to easily wear an electroencephalogram measurement device by himself or herself, it is an example to adopt electrodes which do not require use of paste (hereinafter referred to as "dry electrodes").
However, use of dry electrodes presents a problem in wearing stability. As one example, when a force acts on a dry electrode, the state of contact between the skin and the dry electrode will change because there is no paste. This results in the electrode position changing even though contact with the skin may be maintained ("electrode shifting"), or the electrode becoming lifted off the skin to create a space between the skin and the electrode, thus disabling electroencephalogram measurement ("electrode disengagement").
Note that a paste has a high viscosity, and serves not only to enhance the electrical conductivity between the skin and the electrode, but also to prevent electrode shifting and electrode disengagement. This conserves the state of contact between the skin and the electrode even when the position of an electrode is slightly changed due to a force acting thereupon, because the paste with a high viscosity will then be deformed to allow the electroencephalogram to be properly measured.
When electrode shifting occurs, the skin will be rubbing against the electrode surface, so that noises may likely be mixed in the measured electroencephalogram. If an electrode disengagement occurs, electroencephalogram measurement will be so affected that it is made impossible. Since the user will not always be in a resting state but will undergo various motions in a daily-life environment, insufficiencies concerning electrode contact, such as electrode shifting and electrode disengagement, are likely to occur. In the present specification, an electrode which has become insufficient in terms of contact or attachment will be referred to as an "insufficient electrode". An insufficient electrode is an electrode in a poor state of attachment, i.e., an electrode which is not in a good state of attachment with the skin, such that an electroencephalogram cannot be properly measured.
In order to reduce insufficiencies of measurement due to such electrode shifting and electrode disengagement, it is necessary to quickly detect if a situation obstructing electroencephalogram measurement has occurred. Conventionally known methods for detecting an unfavorable situation for electroencephalogram measurement are: the methods in Japanese Examined Utility Model Publication No. 7-3347 ("hereinafter Patent Document 1"); Japanese Laid-Open Patent Publication No. 2006-212348 ("hereinafter Patent Document 2"); Japanese Laid-Open Patent Publication No. 2006-6665 ("hereinafter Patent Document 3"); and the specification of Japanese Patent No. 4465414 ("hereinafter Patent Document 4"), which will be described below.
Patent Document 1 discloses a method of flowing a weak current through an electroencephalogram electrode, calculating a resistance value (contact resistance) between the skin and the electrode from the measured voltage value, and estimating a state of contact between the skin and the electrode. As a result, insufficiencies concerning the state of electrode attachment are detected (see Patent Document 1, page 3, left column, second paragraph).
In Patent Document 2, a coil is provided near an electrode (FIG. 2 of Patent Document 2), and a voltage is applied to the coil. Based on whether a resultant induced current in the electrode is superposed on the electroencephalogram waveform or not, it is determined as to whether the electrode and the scalp are in contact (Patent paragraph [0038] of Document 2).
In Patent Document 3, measurements are taken of a plurality of "electroencephalogram channels", each electroencephalogram channel defining an electroencephalogram signal to be measured based on the potential difference between a pair of electrodes. In other words, a plurality of pairs of electrodes are provided, and an electroencephalogram signal is measured by each pair. Then, for each electroencephalogram channel, a Signal (=signal to be measured) and Noise (=any signal other than the signal to be measured) are calculated. Through a comparison of the S/N ratio against a threshold value, it is determined as to which electroencephalogram channel is suffering from a measurement insufficiency (paragraph [0028] of Patent Document 3).
In Patent Document 4, insufficiencies of wearing between electrodes for electroencephalogram measurement is distinguished via impedance checks. This makes it possible to identify whether electrodes are in contact with the skin of the user or not. The impedance check, as used in Patent Document 4, is an approach of flowing a very minute amount of current between two electrodes to measure a value of resistance existing between the places where the two electrodes are in contact with the skin. When electrode disengagement, user perspiration, or the like occurs to prevent proper detection of an electroencephalogram, there is an increase in the resistance value between the electrodes. Therefore, by performing impedance checks to measure resistance values between electrodes, it becomes possible to determine which combination of electrodes fails to attain proper contact (paragraphs [0167], [0168] of Patent Document 4).

Electroencephalogram measurement system, electroencephalogram measurement method, and program thereof