CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of U.S. Provisional Application 60/890,875, filed on Feb. 21, 2007, and is a continuation in part of U.S. patent application Ser. No. 11/312,898, filed on Dec. 20, 2005, which claims priority of U.S. Provisional Application 60/740,743, “METHODS AND SYSTEMS FOR DETECTING CONCEALED OBJECTS,” filed on Nov. 30, 2005, all of which are incorporated by reference herein in their entirety. 


   BACKGROUND 
   The present teachings relates to detection of concealed objects. 
   The detection of weapons, contraband, and other concealed objects is of significant interest at security checkpoints and the like. Explosives detection for aviation security has been an area of federal concern for many years. 
   Much effort has been focused on direct detection of explosive materials in carry-on and checked luggage, but techniques have also been developed to detect and identify residual traces that may indicate a passenger&#39;s recent contact with explosive materials. The trace detection techniques use separation and detection technologies, such as mass spectrometry, gas chromatography, chemical luminescence, or ion mobility spectrometry, to measure the chemical properties of vapor or particulate matter collected from passengers or their carry-on luggage. Parallel efforts in explosives vapor detection have employed specially trained animals, usually dogs, as detectors. 
   The effectiveness of chemical trace analysis is highly dependent on three distinct steps: (1) sample collection, (2) sample analysis, and (3) comparison of results with known standards. If any of these steps is suboptimal, the test may fail to detect explosives that are present. When trace analysis is used for passenger screening, additional goals may include nonintrusive or minimally intrusive sample collection, fast sample analysis and identification, and low cost. While no universal solution has yet been achieved, ion mobility spectrometry is most often used in currently deployed equipment. 
   Several technologies have been developed and deployed on a test or prototype basis. One approach is to direct passengers through a portal, similar to a large doorframe, that contains detectors able to collect, analyze, and identify explosive residues on the person&#39;s body or clothing. The portal may rely on the passenger&#39;s own body heat to volatilize traces of explosive material for detection as a vapor, or it may use puffs of air that can dislodge small particles as an aerosol. Alternatively, a handheld vacuum “wand” may be used to collect a sample. In both cases, the collected samples are analyzed chemically. 
   A different approach is to test an object handled by the passenger, such as a boarding pass, for residues transferred from the passenger&#39;s hands. In this case, the secondary object is used as the carrier between the passenger and the analyzing equipment. The olfactory ability of dogs is sensitive enough to detect trace amounts of many compounds, but several factors have inhibited the regular use of canines as passenger explosives trace detectors. Dogs trained in explosives detection can generally only work for brief periods, have significant upkeep costs, are unable to communicate the identity of the detected explosives residue, and require a human handler when performing their detection role. In addition, direct contact between dogs and airline passengers raises liability concerns. 
   Metallic objects can be detected utilizing a magnetometer. Unfortunately, this approach does not detect most organic polymer and composite materials that may be used to fabricate firearms, explosives, and other objects which are frequently the subject of security inspections. 
   In another approach, millimeter wave electromagnetic radiation is applied to provide images that can reveal objects concealed by clothing. This approach typically depends on the ability of a human inspector to visually detect one or more suspect objects from the resulting image. Accordingly, there are intrinsic speed limitations in these approaches, and such approaches are subject to variation with the ability of different inspectors. Moreover, because these systems can provide detailed images of body parts that are ordinarily intended to be hidden by clothing, utilization of a human inspector can be embarrassing to the person being inspected, and may pose a concern that privacy rights are being violated. Thus, there is an on going demand for further contributions in this area of technology. 
   In conventional systems, infrared detection of concealed objects has failed in the most cases because infrared camera reacts only on heat differences between the object under cloth and background cloth. If an object is in contact with a body (for example, a human body) for long enough to come to approximate thermal equilibrium, this difference in some cases will be negligible and contrast of the concealed object (for example, under cloth) is not enough for detection. 
   BRIEF SUMMARY 
   One embodiment of the method of these teachings for detecting the presence of concealed objects is passive, does not require any radiation source, uses thermal radiation of a body as a source of radiation. Other embodiments include unique systems, devices, methods, and apparatus to determine the presence of a concealed object. 
   In one instance, an embodiment of the system of these teachings includes a temperature modifying component capable of modifying the temperature distribution of an emitting body, one or more image acquisition devices capable of receiving electromagnetic radiation from the emitting body and of acquiring an image of the emitting body from the received electromagnetic radiation. 
   In another instance, an embodiment of the system of these teachings also includes an analysis component capable of identifying one or more regions in the image, the analysis component being capable of receiving one or more images from the one or more image acquisition devices. 
   Methods of utilizing the system of these teachings and computer usable medium having computer readable code embodied therein, the computer readable code being capable of causing one or more processors to execute the methods of these teachings, are also disclosed. 
   For a better understanding of the present invention, together with other and further needs thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a graphical schematic representation of an embodiment of the system of these teachings; 
       FIG. 2  is a graphical schematic representation of another embodiment of the system of these teachings 
       FIG. 3  is a schematic block diagram representation of an embodiment of the analysis component of an embodiment of the system of these teachings; 
       FIG. 4  shows a schematic block diagram representation of another embodiment of the analysis component of an embodiment of the system of these teachings; 
       FIG. 5  is a graphical schematic representation of yet another embodiment of the system of these teachings; 
       FIG. 6  is a graphical schematic representation of an exemplary embodiment of the system of these teachings; 
       FIGS. 7   a - 7   g  are pictorial representations of results from an exemplary embodiment of the system of these teachings; 
       FIGS. 8   a - 8   f  are pictorial representations of other results from an exemplary embodiment of the system of these teachings; 
       FIG. 9A  depicts a schematic drawing of one embodiment of the temperature modifying component of these teachings; 
       FIG. 9B  depicts a schematic drawing of another embodiment of the temperature modifying component of these teachings; 
       FIG. 10A  depicts a schematic drawing of a subcomponent of an embodiment of the temperature modifying component of these teachings; 
       FIG. 10B  depicts a schematic drawing of another instance of a subcomponent of an embodiment of the temperature modifying component of these teachings; 
       FIG. 11  depicts a schematic representation of a detailed embodiment of the system of these teachings; 
       FIG. 12  depicts a schematic representation of another detail embodiment of the system of these teachings; 
       FIG. 13  depicts a schematic representation of embodiment of the scanning device according to present teachings; 
       FIG. 14  depicts a schematic representation of another embodiment of the system of these teachings; 
       FIG. 15  depicts one embodiment of the component for reducing the thickness of the air layer according to these teachings; 
       FIGS. 16   a - 16   c  depict views of embodiments of the component for reducing the thickness of the air layer according to these teachings; 
       FIG. 17  depicts another embodiment of the component for reducing the thickness of the air layer according to these teachings; 
       FIG. 18  depicts a schematic representation of yet another embodiment of the system of these teachings; and 
       FIG. 19  depicts a schematic representation of a further embodiment of the system of these teachings. 
   


   DETAILED DESCRIPTION 
   In one instance, an embodiment of the system of these teachings includes one or more temperature modifying components capable of modifying the temperature distribution of an emitting body, one or more image acquisition devices capable of receiving electromagnetic radiation from the emitting body and of acquiring an image of the emitting body from the received electromagnetic radiation. 
   In another instance, an embodiment of the system of these teachings also includes an analysis component capable of identifying one or more regions in the image, the analysis component being capable of receiving one or more images from the one or more image acquisition devices. 
   In one embodiment of these teachings, a thermal balance is disturbed by preheating or precooling. The image contrast for a concealed object is increased and the concealed object can be detected. In one embodiment, detection is by an operator; in another embodiment, detection is by an automatic device. 
   One embodiment of the system of these teachings is shown in  FIG. 1 . Referring to  FIG. 1 , the one or more temperature modifying components  20  modifies the temperature distribution of a body  10 . The body  10  emits electromagnetic radiation that is received by one or more acquisition devices  25 . The one or more acquisition devices  25  acquire one or more images obtained from the received electromagnetic radiation. In one embodiment, the body  10  emits infrared electromagnetic radiation having a wavelength between about 0.75μ to about 1000μ. (The infrared range of electromagnetic radiation is typically divided into a near infrared range, from about 0.75μto about 1.4μ, a short wavelength infrared range, from about 1.4μ to about 3μ, a mid wavelength infrared range, from about 3μ to about 8μ, a long wavelength infrared range, from about 8μ to 15μ, and a far infrared range from about 15μto about 1000μ. It should be noted that the systems of these teachings can be utilized in any of these ranges or in any combination of this ranges.) In one instance, the acquisition device  25  is an infrared camera. In the embodiment shown in  FIG. 1 , the one or more images obtained by the one or more acquisition devices  25  are provided to one or more displays  30 . 
   Modifying the temperature distribution of a body having a concealed object (such as, but not limited to, and object concealed under clothing covering the body) allows detection of the concealed object from an image obtained from the electromagnetic radiation emitted by the body. 
   The modification of the temperature distribution of the body  10  can be obtained by heating the body  10  by means of the one or more temperature modifying components  20 , cooling the body  10  by means of the one or more temperature modifying components  20 , or a combination of cooling and heating. In one instance, the temperature modification is obtained by convection or by convection with forced air (such as, but not limited to, providing a stream of air at a different temperature, the stream being directed at the body  10 ). In one embodiment the stream of air (gas) is produced by a forced flow component (a fan in one embodiment). It should be noted that, while in some embodiments a single temperature modifying component, other embodiments have a number of temperature modifying components. Embodiments in which the temperature modifying components are placed at different locations of the body (around the periphery) in order to obtain temperature modification over the entire body are within the scope of these teachings. 
   Another embodiment of the system of these teachings is shown in  FIG. 2 . Referring to  FIG. 2 , the system shown therein also includes an analysis component  35  receiving the one or more images from the one or more image acquisition devices  25 . The analysis component  35  is capable of identifying one or more regions in the one or more images. The one or more images having the one or more regions identified are then provided to the display  30 . 
   In one instance, the analysis component  35  is also capable of enhancing an image attribute in the one or more regions. Exemplary embodiments of the image attribute are, but these teachings is not limited only to this embodiments, contrast or color. The one or more images having the enhanced image attribute in the one or more regions are then provided to the display  30 . 
   A block diagram representation of an embodiment of the analysis component  35  is shown in  FIG. 3 . Referring to  FIG. 3 , the embodiment shown therein includes a pre-processing component  42  capable of enhancing detectability of the one or more regions in the one or more images received from the acquisition device  25 . The embodiment shown in  FIG. 3  also includes a region detecting component  55  capable of identifying the one or more regions in the one or more preprocessed images and a region analysis component  50  capable of determining characteristics of the one or more regions. In one instance, but these teachings is not limited to only this embodiment, the characteristics include moment invariants. 
   In the embodiment shown in  FIG. 3 , the preprocessing component  42  includes a noise reduction component  37  capable of increasing a signal to noise ratio in the one or more images and a contrast enhancing component. The contrast enhancing component, in the embodiment shown in  FIG. 3 , includes a histogram equalization component  40  (see, for example, W. K. Pratt, Digital image Processing, ISBN0-471-01888-0, pp. 311-318, which is incorporated by reference herein) and an adaptive thresholding component  45  capable of binarizing an output of the histogram equalization component  40 . (For adaptive thresholding, see, for example, but not limited to, Ø. D. Trier and T. Taxt, Evaluation of binarization methods for document images, available at http://citeseer.nj.nec.com/trier95evaluation.html, also a short version published in IEEE Transaction on Pattern Analysis and Machine Intelligence, 17, pp. 312-315, 1995, both of which are incorporated by reference herein.) In one embodiment, the binary output of the histogram equalization component is downsampled to obtain a downsampled image (in order to save processing time of the region detecting component  55 ). In one instance, the noise reduction component  37  is an adaptive noise reduction filter such as, but not limited to, a wavelet based noise reduction filter (see, for example, Mukesh Motwani, Mukesh Gadiya, Rakhi Motwani, and Frederick C, Harris, Jr., “A Survey of Image Denoising Techniques,” in Proceedings of GSPx 2004, Sep. 27-30, 2004, Santa Clara Convention Center, Santa Clara, Calif., and Scheunders P. Denoising of multispectral images using wavelet thresholding.—Proceedings of the SPIE Image and Signal Processing for Remote Sensing IX, 2003, p. 28-35, both of which are incorporated by reference herein). 
   In one instance of the embodiment shown in  FIG. 3 , the region detecting component  55  includes segmentation to identify the one or more regions. (See for example, but not limited to, Ch.  9 , Image Segmentation, in Handbook of Pattern Recognition and Image Processing, ISBN 0-121-774560-2, which is incorporated by reference herein, C. Kervrann and F. Heitz, “A Markov random field model based approach to unsupervised texture segmentation using local and global spatial statistics,” IEEE Transactions on Image Processing, vol. 4, no. 6, 1995, 856-862. http://citeseer.ist.psu.edu/kervrann93markov.html, which is incorporated by reference herein, and S. Liapis and E. Sifakis and G. Tziritas, “Colour and Texture Segmentation Using Wavelet Frame Analysis, Deterministic Relaxation, and Fast Marching Algorithms,” http://citeseer.ist.psu.edu/liapis04colour.html, which is incorporated by reference herein.) In one embodiment, the region detecting component  55  labels each connective area (region) by unique label. Each region labeled is processed by the region analysis component  50  in order to determine shape characteristics (moment invariants, in one embodiment). 
   In one instance of the embodiment shown in  FIG. 3 , the region analysis component  50  characteristics include moment invariants (see for example, Keyes, Laura and Winstanley, Adam C. (2001) USING MOMENT INVARIANTS FOR CLASSIFYING SHAPES ON LARGE_SCALE MAPS.  Computers, Environment and Urban Systems  25. available at http://eprints.may.ie/archive/00000064/, which is incorporated by reference herein). In the embodiment in which shape characteristics are important for object detection, the moments will identify concealed objects. (For example, circled objects have all moments starting from the second equal zero. Symmetrical objects have specific moments, etc.) Other embodiments of the characteristics obtained from the region analysis component  50  include, but are not limited to, multiscale fractal dimension and contour saliences, obtained using the image foresting transform, fractal dimension and Fourier descriptors (see for example, R. Torres, A. Falcao, and L. Costa. A graph-based approach for multiscale shape analysis. Pattern Recognition, 37(6):1163--1174, 2004, available at http://citeseer.ist.psu.edu/torres03graphbased.html, which is incorporated by reference herein). 
   In one instance, if a region with given characteristics (a given moment) values is detected, the region provided to the one or more displays  30  is enhanced by contrast, or by color. 
   In one instance, in the embodiments described above, some of the elements of the analysis component  35 , such as, but not limited to, the noise reduction filter  37 , histogram equalization component  40 , the adaptive thresholding component  45 , or/and the unsupervised segmentation component  55 , are adaptive. Adaptation can be accomplished or enhanced by means of an adaptation component  62 . In one embodiment, the adaptation component  62  includes a database  60  (in one instance, a computer usable medium for storing data for access by a computer readable code, the computer usable medium including a data structure stored in the computer usable medium, the data structure including information resident in a database, referred to as “a database”) and a neural network component  65 . It should be noted that although the embodiment shown in  FIG. 3  utilizes a neural network for the adaptation (including optimizing of parameters), other methods of optimization are also within the scope of these teachings. The adaptation component  62  can, in one embodiment, include a component utilizing artificial intelligence or decision logic (including fuzzy decision logic). In one embodiment, substantially optimal parameters of some of the elements of the analysis component  35 , such as, but not limited to, the noise reduction filter  37 , histogram equalization component  40 , the adaptive thresholding component  45 , or/and the unsupervised segmentation component  55 , are determined (within a training procedure) by means of the neural network  65  and the database  60 . 
     FIG. 4  shows another block diagram representation of an embodiment of the analysis component  35 . Referring to  FIG. 4 , the output of the region processing component  55  including the shape characteristics (moment invariants) and input from an optimizing component (the neural network) and the database are provided to a decision component  70 . The decision component  70  can be, but is not limited to, a component utilizing artificial intelligence or another neural network or decision logic (including fuzzy decision logic) (see for example, O. D. Trier, A. K. Jain and T. Taxt, “Feature extraction methods for character recognition—A survey,” Pattern Recognition 29, pp. 641-662, 1996, available at http://citeseer.ist.psu.edu/trier95feature.html, which is incorporated by reference herein, Fernando Cesar C. De Castro et al, “Invariant Pattern Recognition of 2D Images Using Neural Networks and Frequency-Domain Representation,” available at http://citeseer.ist.psu.edu/29898.html, which is also incorporated by reference herein). The decision component  70 , in one embodiment, can supplement or replace the display  30  or, in another embodiment, can provide an alarm. 
   During application of an embodiment of the system of these teachings, the presence of concealed objects is detected by modifying a temperature distribution of an emitting body (where the emitting body may contain concealed objects), acquiring one or more images produced by the electromagnetic radiation emanating from the emitting body after the temperature distribution has been modified, and providing the one of more images for detection of the presence of concealed objects. In one embodiment, the method of detecting the presence of concealed objects can include enhancing the detectability of one or more regions in the one or more acquired images before providing the one or more images for detection of the presence of concealed objects, In another instance, the method can also include identifying the one or more regions in the one or more images and determining characteristics of the one or more regions. In yet another instance, the method includes enhancing an image attribute in the one or more regions and displaying the one or more images. In another embodiment, the method of these teachings also includes detecting the presence of concealed objects from the identified one or more regions and the characteristics (such as, but not limited to, moment invariants) of the one or more regions. 
   In a further instance of the method of these teachings, at least one step from the steps of enhancing detectability of one or more regions, identifying the at least one region or determining characteristics of the at least one region is performed adaptively and the method also includes the step of enabling substantially optimal performance of the at least one adaptive step. 
   In one embodiment, the step of enhancing detectability of one or more regions includes increasing a signal to noise ratio in the one or more images. In another embodiment, the detectability is enhanced by enhancing contrast of the one or more images. 
     FIG. 5  is a graphical schematic representation of yet another embodiment of the system of these teachings. Referring to  FIG. 5 , the embodiment shown therein includes the one or more temperature modifying components  20  capable of modifying the temperature distribution of the emitting body  10 , the one or more image acquisition devices  25  capable of receiving the electromagnetic radiation emanating from the emitting body  10  and of acquiring one or more images of the emitting body  10  from the received electromagnetic radiation. In the embodiment shown in  FIG. 5 , the one or more acquisition devices  25  are operatively connected to one or more processors  75  and to one or more computer usable media  80 . The one or more computer usable media  80  has computer readable code embodied therein, the computer readable code being capable of causing the one or more processors to execute the methods of these teachings. In one embodiment, the computer readable code is capable of causing the one or more processors  70  to receive the one or more images from the one or more image acquisition devices  25 , to enhance the detectability of one of more regions in the one or more images and to provide the one or more images to a detection component. 
   In one instance, the detection component is the display  30 , which is also operatively connected to the one or more processors  70 . In another instance, the detection component includes computer readable code embodied in the one or more computer usable media  80  and another computer usable medium  85  for storing data for access by the computer readable code, the other computer usable medium comprising a data structure stored in the other computer usable medium  85 , the data structure including information resident in a database used by the computer readable code in detecting the presence of objects. It should be noted that embodiments in which the one or more computer usable media  80  and the other computer usable medium  85  are the same computer usable medium are within the scope of these teachings. 
   The display element  30 , the one or more acquisition devices  25 , the one or more processors  70 , the computer usable medium  80 , and the other computer usable medium  85  are operatively connected by means of a connection component  77  (the connection component may be, for example, a computer bus, or a carrier wave). 
   The block diagram representation of an embodiment of the analysis component  35  shown in  FIG. 3  or  4  can be implemented, in one embodiment, by means of the computer readable code embodied in the one or more computer usable media  80  and, in some instances, by means of the data structure, including information resident in the database, comprised in the other computer usable medium  85 . In those embodiment, the computer readable code is also capable of causing there one or more processors  72  identify one or more regions in the one or more images and to determine characteristics of the one or more regions, or/and increase a signal to noise ratio in the one or more images, or/and enhance contrast into one or more images. In one instance, the computer readable code is capable of causing the one or more processors  70  to utilize wavelet based noise reduction methods. In another instance, the computer readable code is capable of causing the one or more processors  70  to enhance contrast by applying histogram equalization to the one or more images and by binarizing, using adaptive thresholding, the one or more images. In yet another instance, the computer readable code is capable of causing the one or more processors  72  applied adaptive techniques in implementing the analysis component  35  and to obtain substantially optimal performance of the adaptive analysis component  35 . 
   In a further instance, in obtaining the substantially optimal performance of the adaptive analysis component  35  or in implementing the detection component, the computer readable code is capable of causing the one or more processors  70  to apply neural network techniques. 
   In order to better describe the methods and systems of these teachings, the following exemplary embodiment is described herein below. One exemplary embodiment of the methods and systems of these teachings is described hereinbelow in which the body  10  is a human body and the object is concealed under cloth. It should be noted that other embodiments are within the scope of these teachings. 
   Referring to  FIG. 6 , thermal body radiation (heat)  245  emanates from an investigated person  180  and is received by an infrared camera  100 . The infrared camera  100  can be stationary, remotely controlled or controlled by operator  120 . The infrared Camera  100  generates an image, which is displayed at display  140 . In one instance, the operator  120  watching the image is a decision maker about concealed object under cloth of the investigated person  180 . The Infrared camera  100  provides an image signal to the computer  160 . The image signal is analyzed, by means of computer readable code (software)  220  embodied in a computer usable medium in the computer  160 , in order to detect the presence of objects concealed under cloth on the investigated person  180 . The computer  160  and the computer readable code  220  represent an embodiment of the analysis component  35 , such as the embodiment shown in  FIG. 3 . In one embodiment, the investigated person  180  is located on a platform  200 . A motion component  215  is operatively connected to the platform  200  and capable of causing rotation of the platform  200 . The motion component  215  is controlled by means of the Computer  160 . The rotation of the platform  200  allows the camera  100  to observe the investigated person  180  from different angles. (In another embodiment, a number of cameras  100  located around the periphery of the location of the person  180  allow observation from different angles. In such an embodiment the platform  200  is replaced by a number of cameras  100  at different positions.) A temperature modifying device  240 , a heating device in the embodiment shown, creates a forced heat stream  260  changing the temperature distribution (heating in this embodiment) of the investigated person  180  to create heat misbalance between the objects under cloth and human body temperature. 
     FIGS. 7   a - 7   g  show results obtained for the exemplary embodiment of  FIG. 6  for different temperature modifying components  240 .  FIG. 7   a  shows an image obtained from the camera  100  without any temperature modification.  FIG. 7   b  shows the image obtained after preheating by forced air.  FIG. 7   c  shows the image obtained after preheating and then cooling, both by forced air.  FIG. 7   d  shows another image obtained from the camera  100  without any temperature modification.  FIG. 7   e  shows the image, corresponding to  FIG. 7   d , obtain after cooling with forced air.  FIG. 7   f  shows yet another image obtained from the camera  100  without any temperature modification in which the object, concealed under a shirt and two sweaters, is almost invisible.  FIG. 7   g  shows an image, obtained from the camera  100 , of the same object as in  FIG. 7   f  after the investigated person has been heated by a forced stream  260  from the radiator  240 . 
     FIGS. 8   a - 8   f  show representations of images obtained utilizing the exemplary embodiment of  FIG. 6  in which the analysis component  35  is an embodiment as shown in  FIG. 3 .  FIG. 8   a  shows an image, obtained from camera  100 , produced by thermal radiation from the body  180  after temperature modification (preheating).  FIG. 8   b  shows a contrasted image created from the image of  FIG. 8   a  by histogram equalization.  FIG. 8   c  is a Binary image that is the output of the adaptive thresholding component. The binary image of  FIG. 8   c  is downsampled (in order to save processing time of the region detecting component  55 ) to obtain a downsampled image shown in  FIG. 8   d . The region detecting component  55 , with input (moment invariants) from the region analysis component  50 , extracts an image including a given symmetrical region (concealed object), shown in  FIG. 8   e . An image (upsampled), shown in  FIG. 8   f , showing the enhanced region (concealed object), is displayed at the display  140 . 
   One embodiment of the temperature modifying method and system of these teachings is described hereinbelow. In one embodiment, the method for modifying temperature includes providing a device according to the current invention that provides a controlled gust (a “gust” as used herein refers both to the pulsed stream of heated gas and a continuous stream of heated gas) of heated gas (hereinafter referred to as air). In one embodiment of the temperature modifying system (shown in  FIG. 9A ), these teachings is not being limited to only this embodiment, the system includes a gust generator  310  comprised of a compressed air line  320  with a pressure switch  330 , a pressure regulator  340 , and a solenoid valve  350 . A heater  360  with a thermocouple  370  and a temperature controller  380  is connected to the line  320  and disposed substantially coaxially in an ejector  390 . The ejector  390 , in one embodiment, comprises an inductor  395  and diffuser  397 . The temperature controller  380  maintains predetermined standby temperature that, corresponding to a construction and thermal mass of the heater  360 , sufficient to heat the intermittent pulses of the compressed air to a predetermined temperature. The air released by the valve  350  through the heater  360 , draws surrounding air through the inductor  395 . Both airflows mix in the diffuser  397  creating single stream with approximately uniform temperature and velocity distribution. Directed appreciably normal to the surface of the clothing covering the body, the resulting gust transfers thermal and kinetic energies that both raises a temperature of the clothing and, by thermal conduction, the underlying body. 
   In another embodiment of the temperature modifying system (shown in  FIG. 9B ), a gust generator  420  comprised of a fan  421  with a deflector  422 . A heater  423  with a thermocouple  424  and a temperature controller  425  disposed in downstream of deflector  422 . The temperature controller  425  maintains predetermined standby temperature that, corresponding to a construction and thermal mass of the heater  423 , ensure heating of gusts of the air from the fan  421  (intermittent gusts, in one embodiment) to a required temperature. Withdrawing the deflector  422  from air path between the fan  421  and the heater  423  opens the airflow through the heater  423  that, directed appreciably normal to the clothes surface, transfers thermal and kinetic energies that both raises a temperature of the clothes and presses them against the underlying body. 
   In another instance of the temperature modifying system ( FIG. 10A  and  FIG. 10B ), the airflow from a gust generator  530 / 540  is divided by a duct branching in two streams from outlets accordingly  531 / 541  and  532 / 542  directed with an account of general shape of the body  533 / 543  accordingly and a distance from the outlets  531 / 541  and  532 / 542  to the body  533 / 543  surface. 
   In yet another embodiment of the temperature modifying system (shown in  FIG. 11 ), the system includes multiple gust generators arranged in line vertically and divided in three zones controlled separately. The generators  550  form a lower zone that covers height, up to which the body is substantially covered by clothing. Middle and top zones comprise respectively generators  551  and  552 . The generators  551  and  552  are activated together with the generators  550  if clothed parts of the body  557  are detected at their corresponding levels. In case shown, generators  550  and  551  would be activated. Automatic detection of the body presence and its height as well as various methods and devices for limiting and directing airflow away from unclothed (or sensitive) body parts are utilized to ensure that the entire body is not exposed to the gust and that the temperature of only a portion of the entire body is modified. (In one instance, the portion of the body receiving the gust of heated fluid is substantially that portion of the body cover by clothing. Sensing techniques include, but not limited to, photodetecting methods, image sensing/machine vision methods, ultrasound methods, capacitive methods and others. Sensing components (not shown) are located at appropriate position (s) in order to allow detection of the body presence, height or/and discriminate between clothed and unclothed sections of the body.) The gust generators  550 ,  551 , and  552  are connected by a manifold  553  to the common fluid (air) line  556  with pressure regulator  554  and pressure switch  555 . This arrangement requires just one temperature controller with the corresponding sensor per zone. In some instances, multiple gusts are applied to the body  557  that cover entire clothed body surface, while the body is being rotated. 
   In another embodiment ( FIG. 12 ), the device comprises multiple gust generators  560  and  561  arranged approximately radially in relation to the body  566 . The gust generator  561  is branched so the airflow from it directed to inner leg surfaces. The gust generators  560  and  561  connected by a manifold  562  to the common air line  565  with pressure regulator  563  and pressure switch  564 . This arrangement requires just one temperature controller with the corresponding sensor. The device travels vertically while the gust is applied that provides for a half body scan. 
   In yet another embodiment ( FIG. 13 ), an exemplary embodiment of a vertical transport mechanism capable of enabling vertical displacement of one or more temperature modifying components, the device comprises the gust generator  570  attached to a carriage  571  (an exemplary embodiment of a supporting member) that also holds an infrared camera  572  (in the embodiment shown, although it should be noted that embodiments in which infrared cameras or other image acquisition devices are stationary are also within the scope of these teachings) and placed slideably on a vertical slide  573  (an exemplary embodiment of a substantially vertical structural member), which affixed to a horizontal member  576  that rotateably connected to a frame  577  (it should be noted that embodiments in which the vertical transport mechanism is stationary are also within the scope of these teachings). A counterweight  575  placed slideably on a vertical slide  574  that affixed to the member  576  opposite to the slide  73 . (Embodiments in which the counterweight includes another gust generator are also within the scope of these teachings. See Figure) Generally the carriage  571  and the counterweight  575  are linked a mechanism (two sheaves and are substantially fixed length connector, one of which is attached to the carriage  571  and the other end attached to the counterweight to  575 , the connector adapted to run on both sheaves) that balances both the carriage  571  and the member  576 , an exemplary embodiment of a transport component. The body  578  is positioned approximately at rotational axis of the member  576 . The carriage  571  with the generator  570  and the camera  572  scans the body  578  in, for example, a spiral pattern. (Sensing components (not shown) are located at appropriate position (s) in order to allow detection of the body presence, height or/and discriminate between clothed and unclothed sections of the body and provide information to a temperature modifying system controller.) 
   The temperature modifying method, in one embodiment, also includes positioning the body at predetermined location (or determining parameters and characteristics of the body) so, that airflow from the gust generator(s) would be directed appreciably normal (perpendicular) to the surface of the clothes (and would not be directed to unclothed portions of the body so that the entire body is not subjected to the airflow). (In other instances, the flow is guided at the emitting body in a predetermined direction.) In this embodiment, data of body parameters is sensed by sensors (not shown) (such as, but not limited to, photodetectors, ultrasound sensors and other location or distance sensors) and is transmitted to a gust generator controller. 
   The temperature modifying method, in one embodiment, also includes applying the gust of heated air to the surface of the clothes resulting in the transmission of thermal and kinetic energies that raises a temperature of the clothes and, by thermal conduction and by pressing the clothing against the body, of the underlying body. Depending on the embodiment of the device used, the application differs in duration and may differ in the air temperature. Commonly for most of the embodiments, according to present invention, the gust controller takes control of the heaters from the temperature controller after the body positioned and turns on full power to the heaters. After a predetermined time delay, a gust is generated that produces a pulse of the heated air. At the end of the gust the gust controller turns the heater control back to the temperature controller. This counteracts thermal inertia of the heaters that leads to both decreasing energy consumption and decreasing size of the heaters. 
   As described herein above, in one embodiment, the method of these teachings also includes capturing the infrared radiation from the clothed body (an object covered by one or more garments) on camera. In one instance, object visibility initially increases. In one instance, object visibility begin to diminish after about 1 to about 3 minutes. 
   In the embodiment in which the gust is a pulsed stream of heated air, the temperature of the pulse is selected to be sufficient to increase the temperature of the clothing that cover in the body (and of the body) by about 20 to about 40 degrees C., producing temperatures of the clothing that cover in the body (and of the body), when the body is located about 30 cm away from the gust generator, of about 45 to about 60 C. In one embodiment, the velocity of the air stream at the body is about 800 to 1100 feet per minute. In another embodiment, the velocity of the air stream at the body is about 800 to 2400 feet per minute (from about 4 to about 12.3 m/sec). In one instance, the distance between the temperature modifying system and the body is about 30 cm to about 1 m. 
   In the embodiment in which the gust of heated air is a substantially continuous stream of heated air or a pulse of heated air of a substantially long-duration, the air stream can be directed substantially perpendicular to the body and can be distributed substantially homogeneously along the body in any direction. In one instance, the air stream can be directed (in a predetermined direction) at the emitting body by means of guiding components, such as, but not limited to, slats or louvers. (The slats or louvers being placed to obtain the predetermined direction.) In one embodiment, the temperature of the stream is selected to be sufficient to increase the temperature of the clothing that cover in the body (and of the body) by about 20 to about 40 degrees C., producing temperatures of the clothing that cover in the body (and of the body), when the body is located about 30 cm away from the gust generator, of about 45 to about 60 C. In one embodiment, the velocity of the air stream at the body is about 800 to 1100 feet per minute. In another embodiment, the velocity of the air stream at the body is about 800 to 2400 feet per minute (from about 4 to about 12.3 m/sec). In one instance, the distance between the temperature modifying system and the body can be about 30 to about 50 cm. 
   It should be noted that embodiments in which the substantially vertical structural member  574  of  FIG. 13  and a counterweight  575  of  FIG. 13  are located to the left of the other vertical member  573  in  FIG. 13  and in which the vertical transport is stationary and means are provided for rotating the emitting body  578  ( FIG. 13 ) are also within the scope of these teachings. One exemplary embodiment shown in  FIG. 14 , where the vertical members are housed in an enclosure  580 . 
   In embodiments in which the emitting body is partially covered by one or more garments, the system of these teachings can also include a component capable of reducing the thickness of a fluid layer between a portion of one or more of the garments and the portion of the emitting body covered by that portion of the one or more garments. (Thickness of the fluid layer, as used herein, is determined in a direction substantially perpendicular to the emitting body.) The fluid (such as, but not limited to, air) between the garments and the emitting body can decrease the contrast of the acquired image, which can be detrimental to recognizing concealed objects. 
   In one instance, the component capable of reducing the thickness of a fluid layer between a portion of one or more of the garments and the portion of the emitting body covered by that portion of the one or more garments includes a material (in one embodiment a flexible material) capable of substantially conforming to the one or more portions of the garments and to the one or more portions of the emitting body covered by the one or more portions of the garments. Exemplary embodiments of the material include, but not limited to, cloth, a net or mesh or a combination of cloth and net or mesh (referred to as an intermeshed material). In the above instance, the component may also include a subcomponent capable of positioning the material in contact with the garments and the emitting body. (Embodiments in which the emitting body is placed in contact with the material are also within the scope of these teachings.) Such a subcomponent can be, but is not limited to, a mechanical device including a holder for an area of the material, a displacement component for moving the material from one position in which it is away from the garments and the emitting body to another position where it is substantially in contact with one or more portions of the garments in the emitting body (exemplary embodiments of displacement components include mobile linkages, slides and other mechanical transport components) and displacement means (such as, but not limited to, motors, x-y displacement systems, etc.). 
     FIG. 15  shows an exemplary embodiment of an intermeshed material  610  mounted on a holding assembly  620  and portions of a displacement component  625 . 
     FIG. 16   a  shows a cross-sectional view of the intermeshed material  610  being displaced towards the emitting body (and the footprints  630  of the lower part of the emitting body-their footprints being wider than the emitting body to indicate a base or a foot). Although in the embodiment shown in  FIG. 16   a  the intermeshed material  610  is being displayed directly in the direction of the emitting body, other embodiments also possible. 
     FIG. 16   b  shows an embodiment in which the intermeshed material is being displaced at an angle (approximately 45° in the embodiment shown) with respect to a normal  635  to a mid-plane  640  of the body. In this embodiment, the intermeshed material can substantially conform to the front and the side of the garment and emitting body and can substantially reduce the depth of the air layer between the garment and the emitting body in both the front and the side of the emitting body.  FIG. 16   c  shows another embodiment in with the intermeshed material forms a W-like shape by having one support  645  located at a position between the two supports  650  of the emitting body. In the embodiment shown in  FIG. 16   c , the holding assembly  620  also includes the support  645  located such that, as the intermeshed material becomes contiguous with the garment and the emitting body, the support  645  is located in a position between the two supports  650  of the emitting body. 
   In another instance, the component capable of reducing the thickness of a fluid layer between a portion of one or more of the garments and the portion of the emitting body covered by that portion of the one or more garments includes a suction component capable of exerting suction on the garment and one or more locations. The exerted suction causes the garment to substantially conform to one or more other portions of the emitting body at a region including at least one more locations substantially opposite to the location at which the suction is applied.  FIG. 17  shows an embodiment of the system of these teachings in which a vacuum suction component  670  is applied to a portion of a garment covered emitting body  675  causing the garment to substantially conform to the body in a region  680  substantially centered at about a location  685  substantially opposite to the location at which the suction is applied. 
   Although the embodiments of the system with these teachings shown in  FIGS. 13 and 14  include one temperature modifying component and one camera being substantially vertically transported, other embodiments are within the scope of these teachings.  FIG. 18  shows an embodiment of the system of these teachings with two temperature modifying components and cameras capable of obtaining an image of the front and on one side of an emitting body. In the embodiment shown in  FIG. 18 , the emitting body only needed to rotate once by substantially 180° in order to obtain a substantially complete image. Another embodiment is shown in  FIG. 19 . In the embodiment shown in  FIG. 19 , the counterweight  575  of  FIG. 13  is replaced by another temperature modifying component  690  (gust generator) and another image acquisition device (camera)  695 . 
   It should be noted that embodiments in which parameters of interest, such as, but not limited to, the temperature at the exit of the temperature modifying component, the displacement speed of the carriage  571 , the operation of the component for reducing the thickness of the fluid layer (whether a material or a suction device) and interaction between the sensing components capable of sensing body presence and the temperature modifying component, can be controlled by a controller components such as a PLC or a computer are within the scope of these teachings. 
   It should be noted that other embodiments, besides the above described exemplary embodiments, are also within the scope of these teachings. 
   The techniques described above may be implemented in one or more computer programs executing on a programmable computer including a processor, a storage medium readable by the processor (including, for example, volatile and non-volatile memory and/or storage elements), and, in some embodiments, also including at least one input device, and/or at least one output device. Program code may be applied to data entered using the input device (or user interface) to perform the functions described and to generate output information, The output information may be applied to one or more output devices. 
   Elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions. 
   Each computer program (computer readable code) may be implemented in any programming language, such as assembly language, machine language, a high-level procedural programming language, an object-oriented programming language, or a combination thereof. The programming language may be a compiled or interpreted programming language. 
   Each computer program may be implemented in a computer program product tangibly embodied in a computer-readable storage device for execution by a computer processor. Method steps of the invention may be performed by a computer processor executing a program tangibly embodied on a computer-readable medium to perform functions of the invention by operating on input and generating output. 
   Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CDROM, any other optical medium, punched cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, or any other medium from which a computer can read. From a technological standpoint, a signal or carrier wave (such as used for Internet distribution of software) encoded with functional descriptive material is similar to a computer-readable medium encoded with functional descriptive material, in that they both create a functional interrelationship with a computer. In other words, a computer is able to execute the encoded functions, regardless of whether the format is a disk or a signal. 
   Although the invention has been described with respect to various embodiments, it should be realized these teachings are also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims.
Methods and systems for detecting the presence of concealed objects. One embodiment of the method of these teachings for detecting the presence of concealed objects is passive, does not require any external radiation source, uses thermal radiation of a body as a source of radiation. Other embodiments include unique systems, devices, methods, and apparatus to determine the presence of a concealed object.