Abstract: A device and method for determining whether or not an image is blurred. The device and method comprises an input part for receiving an image; a block classification part for dividing the received image into blocks and classifying the divided blocks into character blocks and background blocks; a character block energy calculation part for calculating an average energy ratio of the character blocks; and a blurring detection part for calculating an average energy ratio of the character blocks and determining whether or not the image is blurred based on a comparison of the average energy ratio with a predetermined threshold.

Abstract: A device and method to make the identification signal of the image feature with a decreased volume of database for the image by using DCT sign characteristic of an arbitrary signal including the image, which can be applied to a new type of passport, credit card, driver's license, ID card, etc that are hard to forge by displaying the face photo together with the corresponding bar code. The device and method to make the identification signal of the image feature can contribute to the overall security system greatly.

Abstract: The present invention relates to a method and system for foreground segmentation in which frames of a video sequence are analyzed in the transform domain to determine one or more features. The features are used to model the background. The background can be modeled as a single Gaussian model with a mean and variance of the features. A current frame is segmented by determining if one or more features of the current frame analyzed in the foreground domain satisfy a threshold between the background model. The threshold value can be based on the mean and/or variance of features. During the segmentation, the mean and variance can be updated based on previous corresponding values and current features to adaptively update the background model. In one embodiment, the frames are divided into a plurality of blocks. A transform is used to analyze the blocks in the transform domain. For example, the transform can be a discrete cosine transform (DCT).

Abstract: A method for determining magnitude and direction of spectral channel drift for several consecutive spectral regions over a wide spectral range. According to the method of the present invention, in-field testing of a spectral filter sequentially irradiated by two blackbody sources is performed to generate a response function of the spectral filter. The response function is ensemble averaged to reduce any noise. Background radiance is then removed to produce a smoothed spectral transmittance function of the spectral filter. The first derivative function of the smoothed spectral transmittance function is determined. The first derivative function is separated into spectral band regions having +/− N pixels on either side of the function minima. The value of N is selected to optimize the detection algorithm sensitivity to change while extending the limit of spectral shift magnitude.

Abstract: An image matching system, method, and program for matching two images even if there is a difference of parallel movement, rotation angle, and scale between two images. A Fourier-Mellin transform is a Fourier transform and a log-polar coordinate transform to a registered image and a matching image. A phase only correlation unit and scalar information-rotation information generation unit generate correction information including scalar information and rotation information based on correlation strength of the phase information based on the transform result, a correction unit corrects the matching image RIM in accordance with the correction information, a parallel movement unit performs phase only correlation based on the image resulting from the correction processing and the registered image, a correlation value generation unit generates a correlation value based on the correlation image data, and judgment unit performs judgment concerning the matching based on the correlation value.

Abstract: In a target detection system two images are obtained of a known target, using two different wavelength filters constituting a hyperspectral line pair. The images are subtracted and the resulting image is analyzed by creating a Y profile of pixel values along a vertical line through the target on the image, and creating an X profile of pixel values along a horizontal line through the target on the image. Values of peak signal, peak noise and mean noise are obtained for each profile. These values are used to test certain criteria, which if not met, results in the selection of a new hyperspectral line pair for analysis. If the criteria are met for a first tested profile, then the tests are applied to the second profile. If the analyses of both profiles meet the criteria, then that hyperspectral line pair being tested is stored as a candidate for future use in target detection.

Abstract: A method and an apparatus are disclosed for generating a model of an object from an image of the object. First, an orientation of the object in the image is determined through the generation of, and subsequent evaluation of, at least a portion of a frequency response of the image. Thereafter, the orientation is used to gauge the object. The gauging provides the necessary dimensional information that becomes a part of the geometrical model of the object. An embodiment is disclosed that generates a geometrical model of a leaded object from the image of the leaded object.

Abstract: Disclosed here is a system for creating maps using multispectral landscape photographed images. The system comprises surface substance analyzing means for analyzing a multispectral landscape photographed image using a spectral information database, on-ground object identifying/analyzing means for identifying an on-ground object using the surface substance analytical result and the on-ground object information database; and outputting means for outputting map information according to the on-ground object identification/analytical result and output setting.

Abstract: Video cameras capture surrounding images, and time code generated by a time code generator is attached to the images. Likewise, when the respective images are captured, the position and inclination of the car are measured by a GPS, a three-axis angle sensor, and a geomagnetic angle sensor, and attached to the respective images. A panoramic image can be produced by connecting together images having the same time code. Performing the aforementioned signal processing for a plurality of routes provides a series of panoramic images. When presenting a panoramic image to a viewer, a panoramic image that is captured at a point closest to a viewpoint of the viewer is identified so that images can be presented to the viewer according to a view direction of the viewer.

Abstract: An image capture apparatus is placed on a desk, etc., and an object to be captured is presented above the apparatus. An illumination device can emit light of a plurality of wavelengths, and a camera captures an image of an object to be captured using different wavelengths. By processing an image using different wavelengths, the material of the object to be captured can be obtained. The captured image is compared with a recorded image stored in the image capture apparatus, etc., and used in image determination.

Abstract: Described herein is a process for objectively and automatically determining spectral endmembers and transforming Spectral Mixture Analysis (SMA) from a widely used research technique into a user-friendly tool that can support the needs of all types of remote sensing. The process extracts endmembers from a spectral dataset using a knowledge-based approach. The process identifies a series of starting spectra that are consistent with a scene and its environment. The process then finds endmembers iteratively, selecting each new endmember based on a combination of physically and statistically-based tests. The tests combine spectral and spatial criteria and decision trees to ensure that the resulting endmembers are physically representative of the scene.

Abstract: A method for improved forensic analysis using multi-view digital imaging of forensic specimens at a plurality of reflected, scattered, emitted, transmitted or absorbed wavelengths to provide new detailed information to distinguish and differentiate forensic materials and samples.

Abstract: A system for automatically classifying and counting people, such as supermarket customers, and associated objects such as shopping trolleys. One or more video cameras view an area traversed by the customers and the video data is processed, in real time, to allocate each customer to one or more of a set of predetermined categories in dependence upon recognition criteria developed to permit reliable classification of customers in relation to the various categories.

Abstract: An apparatus and method of analysis for three-dimensional (3D) physical phenomena. The physical phenomena may include any varying 3D phenomena such as time varying polar ice flows. A repesentation of the 3D phenomena is passed through a Hilbert transform to convert the data into complex form. A spatial variable is separated from the complex representation by producing a time based covariance matrix. The temporal parts of the principal components are produced by applying Singular Value Decomposition (SVD). Based on the rapidity with which the eigenvalues decay, the first 3-10 complex principal components (CPC) are selected for Empirical Mode Decomposition into intrinsic modes. The intrinsic modes produced are filtered in order to reconstruct the spatial part of the CPC. Finally, a filtered time series may be reconstructed from the first 3-10 filtered complex principal components.

Abstract: A method is disclosed herein for evaluating quality of an image. The disclosed method contemplates receiving a spectral image and extracting a plurality of pixels therefrom. The plurality of pixels are converted into a plurality of spectral vectors, wherein each element in each spectral vector represents a property of a respective one of N spectral bands. The plurality of spectral vectors are then categorized into a set of M classes. The method further includes the step of computing a mean vector for each of the M classes based upon the spectral vectors associated therewith. Next, spectral similarity values between pairs of the mean vectors are computed. The distribution of these spectral similarity values may then be analyzed in order to obtain information relevant to image quality.

Abstract: A method for defining targets in hyperspectral image data of a scene, has the steps: (1) identifying a target within the scene; (2) fitting a plurality of conjoined hyperplanes about the target in the scene; and (3) fitting a shape to the identified target by shrinkwrapping the hyperplanes about the target by translating and rotating the hyperplanes until a specified fit parameter is satisfied.

Abstract: A method is disclosed herein for measuring similarity between a first vector and a second vector wherein (i) each element of the first vector represents a first reflectance associated with a respective one of a plurality of spectral bands, and (ii) each element of the second vector represents a second reflectance associated with a respective one of such plurality of spectral bands. The method contemplates determining a magnitude difference and a shape difference between the first vector and the second vector. A similarity between the first vector and the second vector is computed on the basis of the magnitude difference and the shape difference. Further, an image processing method is disclosed herein in which a first input pixel is extracted from a received spectral image or other data source. The first input pixel is converted into a first vector, wherein each element in the first vector represents a reflectance of a respective one of a plurality of spectral bands.

Abstract: An image extraction method picks up an image of an object positioned in front of a background using wavelengths in a visible light region, picks up an image of the object positioned in front of the background using wavelengths in an infrared region, and extracts only the object based on the picked up images. At least a surface of the background is formed by an organic dye.

Abstract: A method and apparatus for improving the signal to noise ratio of an information carrying signal wherein a wavelet transform up to a predetermined level is computed, a frequency thresholded signal which is indicative of noise is derived from the wavelet transform, and the frequency thresholded signal is subtracted from the information carrying signal.

Abstract: Described herein is a process for objectively and automatically determining spectral endmembers and transforming Spectral Mixture Analysis (SMA) from a widely used research technique into a user-friendly tool that can support the needs of all types of remote sensing. The process extracts endmembers from a spectral dataset using a knowledge-based approach. The process identifies a series of starting spectra that are consistent with a scene and its environment. The process then finds endmembers iteratively, selecting each new endmember based on a combination of physically and statistically-based tests. The tests combine spectral and spatial criteria and decision trees to ensure that the resulting endmembers are physically representative of the scene.

Abstract: The present invention provides an instrument and methods for a multispectral optical technique that can simultaneously classify individual biological cells within mixed populations. This invention, known as Multispectral Taxonomic Identification (MTID), shows that microscopy can be combined with a software analysis program to measure and categorize the fluorescence and other spectroscopically identifiable signals from complex populations of cells in situ, without cultivation. The invention thus enables high-throughput screening of cells for taxonomic classification.

Abstract: A Thermal Luminescence Water Monitor system and method for real-time remote sensing and identification of chemical and biological materials (CBMs) in a liquid source, comprising an irradiation component having a microwave radiation source tuned to water's vibration-rotation exciting energy, a glass cell for holding a liquid sample contained within a sealed chamber for its irradiation and concomitant liberation of thermal luminescence, a spectrometer analysis component for collecting and processing thermal luminescence emissions, a neural network component for filtering thermal luminescence difference-spectra components and pattern recognition of predetermined CBMs to determine their presence in the liquid source.

Abstract: A gray scale image or a color image is entered for wavelet transformation. A layout feature is determined from a coefficient of the lowest frequency band after the wavelet transformation. A shape feature is determined from a coefficient of the second lowest frequency band after wavelet transformation. Furthermore, a texture feature is determined from the average and deviation of frequency bands excepting the lowest frequency band after wavelet transformation.

Abstract: A method for detecting anomalies in a digitized complex signal analyzed by a detection unit, including a machine learning and a diagnosis of the intensity and/or the rarity of an anomaly, the learning including the steps of: 1.1 selecting sequences of values of the signal; 1.2 transforming the signal to extract therefrom characteristics of a type easily extracted by a human eye; and 1.3 reducing number n of digital data by an automatic compression; the diagnosis including the steps of: 2.1 applying steps 1.1 to 1.3 to a polling window (Fk) likely to include an anomaly; 2.2 comparing the obtained vector with a reference defined according to the same transformation and compression structure.

Abstract: This invention relates to an improvement matching algorithm for analysing an X-ray images including an adaptive wavelet function as a linear combination of basic circular wavelet function which is an optimal wavelet function using dilations and shift of circular wavelets as building blocks. The resulting algorithm sequentially selects the most significant coefficient as one term on the linear combination that approximates the object. The matching results satisfy properties of rotation invariance, enabling match using only one angle view. The matched wavelet for other views can be quickly obtained by simply rotating the one matched result to the right angle.

Abstract: Apparatus and methods are provided for embedding or embedding digital data into an analog host or cover signal. A distributed signal feature of the cover signal in a particular domain (time, frequency or space) is calculated and compared with a set of predefined quantization values corresponding to an information symbol to be encoded. The amount of change required to modify the signal feature to the determined target quantization value is calculated and the cover signal is modified accordingly to so change the feature value over a predefined interval. Information symbols are extracted by the opposite process. In one embodiment, the predefined value is a short term autocorrelation value of the cover signal.

Abstract: A device for locating a lost target or for surveillance and monitoring of an area for a target having spectral and spatial profiles comprises a digital multi-spectral camera aimed at or scanning an area of interest, the camera generating spectral and spatial output; and a computer including a program for processing in real-time the output of the camera, triggering an alarm when the target is detected from the output.

Abstract: An acquisition is made of a base digital image containing the paddle, and the base image is subdivided into rows of N elementary pixels respectively assigned luminous intensity values, the rows of elementary pixels all being parallel to a general direction of graduation of the paddle. N autocorrelations of the vector of luminous intensity values associated with the row of elementary pixels are made for each row, with respectively the vector and the N−1 vectors successively shifted by 1 elementary pixel, so as to obtain for each row a vector of N autocorrelation values. A Fourier transform treatment is carried out on each autocorrelation vector, in order to obtain an energy frequency spectrum. The energy value at the frequency of the graduated marks is compared for each spectrum with a predetermined threshold value and the presence of the paddle is deduced therefrom.

Abstract: An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter.

Abstract: Image acquisition and analysis systems and methods are provided. A ray-based approach may be used to process images for cell-based assays. Such cell-based assays may be used to evaluate drugs or other compounds or to perform other biological studies. A scanning laser microscope or other equipment may be used to gather image data from fluorescently-marked cells or other suitable specimens. The rays are radially-oriented with respect to the cell nuclei. Seed points within the nuclei may be identified. The rays may extend outward from the seed points or other suitable ray origins until the rays are terminated according to ray termination criteria. The intensity of the image data that is associated with each of the rays may be analyzed to generate various parameters. For example, a peak intensity of the image data along each ray may be identified. Statistical calculations may be performed.

Abstract: The two-dimensional power spectrum of an input image, which is obtained by computing its two-dimensional Fourier transform, is segmented into a plurality of blocks (5×5) on the two-dimensional coordinate system, and the standard deviations of power spectrum components of blocks (5×3) of interest of those segmented blocks are computed. By masking the computed standard deviations in units of blocks (matrix of standard deviations) using predetermined mask patterns prepared in units of directions of interest, the sums of the standard deviations are computed as feature amounts in units of directions, and the directionality of the input image is determined based on the feature amounts. The feature amounts computed for the input image and the directionality determination result are stored in correspondence with each other, and a similar image search is made using the stored information.

Abstract: A method and system that include a first measurement signal and a second measurement signal that can be input to first and second filters. The filters can be subject to a first constraint to minimize the energy difference between the first and second measurement signals on a per frequency basis, and subject to a second constraint that includes a model frequency and phase response. By adapting the filters subject to the two constraints, coherent differences between the two measurement signals can be identified. In one embodiment, the system can be applied to Synthetic Aperture Radar (SAR) data.

Abstract: A method and apparatus for determining a shape of a shim that can be inserted between a first body, such as a strut torque box, and a second body, such as a torque box skin, is disclosed. The strut torque box is marked with a plurality of retro-reflective markers at the desired locations needing to be shimmed. The positions of the markers are measured using digital photogrammetry equipment yielding a plurality of measured points. The measured points define a surface of the first body. The locations of the measured points are transformed relative to a surface of the second body to yield a profile of the shape of the shim. The present method and apparatus have the advantage of considerably reducing the labor required for manual shim measurement using gauges by allowing multiple shim points to be measured simultaneously and without the pre-assembly of the strut torque box and torque box skin.

Abstract: An angularly multiplexed store contains filters derived from prior examination of input image reference samples, a spectrum analyzer produces spectral data representing the frequency spectrum of the input image under examination, a computer produces an encoded map of the spectral data representing the input image frequency spectrum. The encoded map is transformed, inputted into the store while close match spectral correlation light beams emerge from the multiplexed store, each having an emerging angle associated with that filter within the multiplexed store producing a close match with the first transform. An array of light beam detectors and a display present images having colors that indicate the nature of the input image such as a type of cancer. An associated memory-retro-reflector arrangement displays characters naming the materials making up the input image such as types of abnormal tissue.

Abstract: Described herein is a process for objectively and automatically determining spectral endmembers and transforming Spectral Mixture Analysis (SMA) from a widely used research technique into a user-friendly tool that can support the needs of all types of remote sensing. The process extracts endmembers from a spectral dataset using a knowledge-based approach. The process identifies a series of starting spectra that are consistent with a scene and its environment. The process then finds endmembers iteratively, selecting each new endmember based on a combination of physically and statistically-based tests. The tests combine spectral and spatial criteria and decision trees to ensure that the resulting endmembers are physically representative of the scene.

Abstract: Described herein is a process for objectively and automatically determining spectral endmembers and transforming Spectral Mixture Analysis (SMA) from a widely used research technique into a user-friendly tool that can support the needs of all types of remote sensing. The process extracts endmembers from a spectral dataset using a knowledge-based approach. The process identifies a series of starting spectra that are consistent with a scene and its environment. The process then finds endmembers iteratively, selecting each new endmember based on a combination of physically and statistically-based tests. The tests combine spectral and spatial criteria and decision trees to ensure that the resulting endmembers are physically representative of the scene.

Abstract: A method for detecting a synchronous signal contained in an input image signal is provided. In the method, horizontal and vertical periods are established during which horizontal and vertical synchronous signal pulses contained in the input image signal are counted, respectively. Then, minimum and maximum horizontal values which correspond to the horizontal synchronous signal pulses contained in the horizontal period are established, and minimum and maximum vertical values which correspond the vertical synchronous signal pulses contained in the vertical period are established. Afterwards, the horizontal and vertical synchronous signal pulses are counted during the horizontal and vertical periods to respectively obtain first and second counted values.

Abstract: A method of compressing an image frame composed of an array of pixels in the form of digital signals comprises a two stage codebook search. In the first stage the pixelated image frame and the pixelated codebook patches are transformed to frequency domain coefficients and a pattern comparison is made between the coefficients of the image patch and the codebook patches to identify a short list of possible match codebook patches by discarding incorrectly matching patterns. In the second stage the image frame is compared with the short list of codebook patches by any desired method, e.g. by pixel comparisons, to select the best matching codebook patch.

Abstract: The three-dimensional orientation of a given object is determined. The given object may comprise an object having surface characteristics which provide poor contrast in representative images of the given object. In a specific embodiment, the object may comprise a golf ball. A model representation is obtained of a reference object, and a run-time image is obtained of the given object. From the run-time image, shape information is obtained for certain identified shapes collectively forming a subset of the visible shapes. The shape information is matched to a number of incremental poses of the model representation varying along three degrees of freedom.

Abstract: A method and system for determining the similarity between an image and at least one training sample is disclosed. This invention is a novel Gabor Feature Classifier (GFC), a principal application of which may be for face recognition. The GFC applies the Enhanced FLD Model (EFM) to an augmented Gabor feature vector derived from the Gabor wavelet transformation of images.

Abstract: A process for determining the health of crops in a field and for correcting deficiencies in the health of the crops is disclosed. The process includes georeferencing aerial photographs of at least a portion of the field, the aerial photographs having a particular spatial resolution; determining the green plane in the aerial photographs thus taken; preparing a relative greenness map of the field based upon the nitrogen reference area, the relative greenness map providing crop status information having spatial resolution equivalent to the spatial resolution of the aerial photographs; converting the relative greenness map to a nitrogen recommendation map having spatial resolution equivalent to the spatial resolution of the photographs; and applying nitrogen to the field according to the nitrogen recommendation map, whereby the nitrogen is applied to the field without loss of spatial information. A process for treating crops is also disclosed.

Abstract: An image processing apparatus substantially performs image processing on an image including first gray-scale conversion processing using a first gray-scale conversion curve. Then, the image processing apparatus performs second gray-scale conversion processing on the processed image using a second gray-scale conversion curve, and displays a composite gray-scale conversion curve combining the first and second gray-scale conversion curves.

Abstract: A multispectral imaging system (1) and method utilize an optical processor (3) for simultaneously comparing an input wavelength spectrum observed in a single spatial pixel in a scene image from a multispectral imager (2) with a plurality of template wavelength spectra to find a correlation. The optical processor exploits the three-dimensional attributes of optical correlation to perform massively parallel correlation processing by modulating (4) respective ones of a plurality of spectral bands of the input wavelength spectrum of an incident light beam (6) with modulating elements (5) to alter at least one property of the incident light beam by a value corresponding to the observed intensity of the input spectrum in the respective spectral band. In a disclosed embodiment, the modulated beam is expanded and transited through a spatial light modulator (7) having a two-dimensional array of modulating elements.

Abstract: A method for converting a high resolution greyscale digital image to a color image using a low resolution digital color image of the same area or region. The low resolution color image is first registered to the high resolution greyscale image. For each pixel in the high resolution greyscale image, three color elements (red, green, blue or RGB) are calculated from the value of the pixel in the greyscale image and the color value (RGB) of the pixel at the same location in the registered color image. After this process, the high resolution greyscale image will have red, green and blue color elements (RGB) to be used and displayed as a color image.

Abstract: The present invention is a method and system of marking data media products by introducing a predetermined tracing substance constituting a security marking into a polycarbonate (or polystyrene) composition during the manufacturing stages of the polycarbonate material into a data media, such as a compact disc (CD) or digital versatile disc (DVD). This marking technique is useful in tracking pirated data and/or sources, such as CDs or DVDs, to thereby prevent future pirating of data. Using mass spectrometry, specific types and/or quantities of isotopes of each tracing substance, on a structural level, are used to indicate a specific marking and product identity characteristics, such as a specific lot number, batch number, manufacturer identity, shipping date and the like. The security marking is preferably invisible to the naked eye. The security marking technique is also useful for tracking, authenticating and quality control purposes.

Abstract: An improved method and apparatus for discriminating between currency bills of different denominations uses an optical sensing and correlation technique based on the sensing of bill reflectance characteristics obtained by illuminating and scanning a bill along its narrow dimension. A series of detected reflectance signals are obtained by sampling and digitally processing, under microprocessor control, the reflected light at a plurality of predefined sample points as a currency bill is moved across an illuminated strip with its narrow dimension parallel to the direction of transport of the bill. The sample data is subjected to digital processing, including a normalizing process, whereby the reflectance data represents a characteristic pattern that is unique for a given bill denomination and incorporates sufficient distinguishing features between characteristic patterns for discriminating between different currency denominations.

Abstract: A method of detecting halftones in the wavelet domain includes determining an energy value for the sub-bands in a wavelet decomposition. The calculated energy values are compared to a model of energy values that are expected when halftone data are not present. If the actual energy values do not conform to the model, halftone data are deemed to be present. In one embodiment, the model defines a pattern of decaying sub-band energy for each sub-band moving from a highest level of the wavelet decomposition to the lowest level of the decomposition. In another embodiment, the expected energy values in the model vary depending upon the bit-rate of compression of the wavelet-domain data.

Abstract: Apparatus and methods are provided for embedding or encoding auxiliary signals into an analog host or cover signal. A replica of the cover signal or a portion of the cover signal in a particular domain (time, frequency or space) is generated according to a stego key specifying modification values to specified parameters of the cover signal. The replica signal is then modified by an auxiliary signal corresponding to the information to be embedded, and inserted back into the cover signal. Embedded auxiliary signals are extracted by generating replicas of received signals and correlating the replicas with the received signals.

Abstract: A method and system for optically recognizing an object from a reference library of known products based on a spectrum of local radius of curvature of the object. A surface portion of an object is illuminated with a pattern of light that permits the extraction of three dimensional coordinates for a set of points on the surface portion of the object. An image data set of the surface portion of the object is then captured with a capture device that is positioned at an angular offset with respect to a source of the light. That is, the combination of the light pattern and the imaging device together generate a two dimensional captured image, from which it is possible to extract the three dimensional coordinates for the set of points on the surface portion of the object. A set of local radii of curvatures are then determined for selected data points in the image data set. A spectrum representing a distribution of the curvatures is then computed for the set of local radii of curvatures.

Abstract: An original image is sharpened by obtaining a first frequency-domain representation of the original image, selecting one or more elements from this first representation based on one more criteria such as element magnitude and frequency, scaling the selected elements according to one or more scale factors, and forming a second frequency-domain representation by combining the scaled selected elements with the unselected elements of the first representation. A sharpened reproduction of the original image may be generated by applying an inverse transform to the second frequency-domain representation. A technique for deriving the value of the one or more scale factors is also discussed.