Abstract: The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape size, and/or position) as needed to best fit the data.

Abstract: A method and system for reducing correlated noise in imagers is disclosed. Methods are described for determining a pixel correction value. Correlated noise in data generated by imagers can be reduced by applying the pixel correction value to adjust image data before being displayed.

Abstract: The invention relates to an image processing method for preserving the edges of objects reproduced in an intensity image and for reducing the noise, including the steps of acquisition of the intensity image in the form of a multidimensional matrix of points (2-D, 3-D), determination of the intensity gradient at each point, defined by its direction ((&thgr;p) and its modulus (∥{right arrow over (G)}p∥), and the passage at each point of a recursive spatial filter having an anisotropic kernel and providing a degree of smoothing which is greater in the direction perpendicular to the direction of the gradient than in the direction of the intensity gradient. The kernel is spherical on the scanning lines which are not normal to the intensity gradient and it is shaped as a flattened sphere whose major dimension extends in the direction of lines normal to the intensity gradient in a scanned point. The invention also relates to a medical X-ray imagine apparatus for carrying out this method.

Abstract: A method an apparatus for detecting lines in medical images is disclosed, wherein a direction image array and a line image array are formed by filtering a digital image with a single-peaked filter, convolving the resultant array with second order difference operators oriented along the horizontal, vertical, and diagonal axes, and computing the direction image arrays and line image arrays as direct scalar functions of the results of the second order difference operations. Advantageously, line detection based on the use of four line operator functions along the horizontal, vertical, and diagonal directions in accordance with the preferred embodiments actually results in fewer computations than line detection based on the use of three line operator functions. In particular, because of the special symmetries involved, 3×3 second order difference operators may be effectively used.

Abstract: An image processing method using memory management and pre-computed look up tables to speed up computations. Application of filters along directions other than image rows is simplified using several structured processing approaches that improve image data cache-ability. Time consuming or repeated computations are pre-computed and stored as look up tables to reduce the time required for image processing and to remove or reduce the need for special purpose image processing hardware.

Abstract: A letter-box filtering circuit and a method of using the same that includes a preprocessing filter circuit and a filtering circuit to reduce or correct the round-off errors generated when displaying an image of 16:9 on a screen of 4:3 in a digital image processing. The letter-box filtering circuit can display the down sampled image based on the 16:9 image without any distortion or reduced distortion.

Abstract: The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape, size, and/or position) as needed to best fit the data.

Abstract: The method identifies a Pixon element, which is a fundamental and indivisible unit of information, and a Pixon basis, which is the set of possible functions from which the Pixon elements are selected. The actual Pixon elements selected from this basis during the reconstruction process represents the smallest number of such units required to fit the data and representing the minimum number of parameters necessary to specify the image. The Pixon kernels can have arbitrary properties (e.g., shape, size, and/or position) as needed to best fit the data.

Abstract: To realize image conversion processing by means of filtering using a multi-tap structure without requiring that a memory to use has a high-speed capability, a merge circuit 102 merges sampled input image signals for every plurality pieces of continuous pixel data and outputs signals, and a memory element 103 stores approximately one frame of output data from the merge circuit 102. The memory element 103 outputs signals to a memory element 104 in accordance with outputs from a memory element 107 which stores control data which are calculated in advance. The memory element 104 stores a larger number of input signals received from the memory element 103 than the number of taps of a filtering circuit 106, and outputs signals to a selection circuit 105. The selection circuit 105 selects signals required by the filtering circuit 106 from input signals received from the memory element 104 and outputs signals to the filtering circuit 106.

Abstract: A system and method for reducing noise using recursive noise level estimation. The system and method for noise reduction substitute a target pixel in a processing window with a weighted average of a plurality of neighboring pixels according to the degree of similarity between the target pixel and the neighboring pixels. The similarity is based on the noise level affecting the image and the local brightness of the processing window. The filter is based on fuzzy logic and filters out noise without smoothing the image's fine details. The filter uses a human visual system (HVS) response to adjust brightness.

Abstract: A filter that filters in the spatial and temporal domain in a single step with filtering coefficients that can be varied depending upon the complexity of the video and the motion between the adjacent frames comprises: a IIR filter, a threshold unit, and a coefficient register. The IIR filter and threshold unit are coupled to receive video data. The IIR filter is also coupled to the coefficient register and the threshold unit. The IIR filter receives coefficients, a, from the coefficient register and uses them to filter the video data received. The IIR filter filters the data in the vertical, horizontal and temporal dimensions in a single step. The filtered data output by the IIR filter is sent to the threshold unit. The threshold unit compares the absolute value of the difference between the filtered data and the raw video data to a threshold value from the coefficient register, and then outputs either the raw video data or the filtered data.

Abstract: A digital de-emphasis filter for a SECAM decoder for converting a sequence of input image data into filtered image data includes at least one recursion register for storing an auxiliary value that is obtained using an input image data value. An arithmetic circuit uses the auxiliary value and a newly input image data value to generate a new auxiliary value, which replaces the contents of the recursion register, and a filtered image data value. To determine the achromatic value in addition to performing de-emphasis filtering, the filter is provided with a device for storing and outputting a value representative of an estimated value of the achromatic value of the SECAM signal, and a first switch for applying and registering the output estimated value into the recursion register at the beginning of each burst gate period of the SECAM signal.

Abstract: An efficient and reliable method that identifies possible reference sites in an image is disclosed. The method emphasizes customizing the identification of reference sites for each application by providing for initialization of various parameters, such as the size of the reference site. The method then uses a series of measurable parameters to filter possible reference sites in the image and produces and ordered set of possible reference sites. The highest-ranking site of the ordered set is expected to be chosen as the reference site for production. A preferred implementation is disclosed that uses multi-resolution images to enhance efficiency of the identification and that specifically measures the symmetry, orthogonality and uniqueness of the windows.

Abstract: A method of processing a sampled input image having pixels which can have missing information at pixel locations to reconstruct an output image therefrom, including providing a mask for the sampled image to identify valid pixel locations; interpolating by convolution with at least one finite impulse response (FIR) filter(s) applied to the information at valid pixel locations to produce reconstructed information for non-valid pixel locations; and adaptively normalizing the reconstructed information for the non-valid pixel locations produced by applying the FIR filter(s) to the mask so that the valid pixels and the reconstructed information at non-valid pixel locations provide a reconstructed image.

Abstract: The invention relates to a system for the processing of a noisy image in a sequence of noisy images which includes means for extracting a noisy temporal sample at a given location in the noisy image and for supplying a corresponding temporally filtered sample in order to form a noise-filtered image. The system includes recursive temporal filtering means which include means for forming a sum of a corresponding sample (Y.sub.t-1) of an already filtered preceding image of the sequence and a corresponding sample [.DELTA..sub.t (x,y)] of a difference image (S.sub.t -Y.sub.t-1) formed between the noisy image and the filtered preceding image and weighted by a recursion factor (K.sub.t); they also include two-dimensional spatial filtering means (F.sub.2D) which are applied to said difference image in order to enhance spatially coherent samples and to supply a measure of probability of motion (.beta..sub.t) which is linked to said spatially coherent samples, and means for applying a scalar function (f.sub.

Abstract: An optical system is provided with an adaptable window element at a Fourier plane for spatial filtering. Having a window element made up of individually addressable pixels provides a substantial improvement in the spatial filtering adaptability and precision. When combined with a computer and sensor, the window may become part of a negative feedback loop, thereby providing the optical system with more consistent reproducibility, higher reliability with graceful degradation, and more precise control over final results.

Abstract: A method for the temporal filtering of a sequence of digitized noisy images includes the evaluation of an anti-causal filtered sample (P.sub.t.sup.A) in order to reconstruct a present noisy sample (I.sub.t.sup.P) of a given pixel in a present image by an anti-causal linear combination of a causal filtered sample (P.sub.t.sup.C) obtained by preliminary causal linear temporal filtering in association with coefficients (b.sub.j.sup.C) and an anti-causal noisy sample (I.sub.t+1.sup.A). To the samples (P.sub.t.sup.C, I.sub.t+1.sup.A) there are assigned weights calculated as functions of a causal gain factor (K.sub.t.sup.C), equal to the inverse of the sum of the coefficients of the causal linear filtering, and an anti-causal continuity coefficient (.alpha..sub.t.sup.A), the weight of the anti-causal sample (I.sub.t+1.sup.A) being equal to the probability of intensity continuity between the anti-causal sample (I.sub.t+1.sup.A) and a previous filtered sample (P.sub.t.sup.C, P.sub.t-1.sup.C) in the sequence.

Abstract: An image data recursive noise filter wherein relatively high spatial frequency components of the image data are either not filtered at all or are filtered to a lesser degree than relatively low spatial frequency components of the image data. This minimizes blurring of fine low-contrast detail and also avoids "freezing" of noise in undetailed moving areas of the image.

Abstract: Digital maps digitized by scanning paper maps are smoothed by identifying regions which should be of a uniform color, empirically selecting sets of colors which the pixels of a given region might have in the raw map, empirically determining the statistical probability of occurrence of pixels of each color of the selected set in the region, defining groups of connected pixels having colors within the selected set, and resetting the color of all the pixels in a group to a predetermined region color if, and only if, the pixels of the group satisfy the determined statistical probability of occurrence. The inventive method provides uniform coloring of the map where desired, without affecting the sharpness of small-print map annotations.

Abstract: Apparatus for frequency-separating input image data, the apparatus comprises a data buffer; a multi-stage filter for performing successive spatial filtering operations on input image data, the multi-stage filter having:(i) a first filtering stage for frequency-separating the input image data into image data representing at least two spatial frequency bands; and(ii) one or more subsequent filtering stages for receiving a subset of image data output by the preceding stage and frequency-separating that image data into image data representing two or more spatial frequency bands;in which data output by each stage which is not part of the subset of the image data to be filtered by a subsequent filtering stage is supplied to the data buffer; and means for combining image data output by the last of the filtering stages and image data buffered in the data buffer.

Abstract: The present invention comprises an apparatus and method for automatically controlling the degree of temporal integration in a real time video image processor. The degree of integration may be determined by a combination of image brightness detected over a specific area of an image and motion detected within specific locations within the image. The apparatus comprises two main components, an integrating processor and integrating controller. The integrating processor receives an incoming analog video signal and converts it in an A/D converter into a series of digital pixel values. These digital pixel values may then be passed through an arithmetic processing unit where each pixel value may be fractionalized and summed with a fractionalized value of a geometrically corresponding pixel or pixels stored in a memory (i.e., temporal or recursive filtration). The sum of these fractionalized pixel values may then in turn be stored in memory as a new pixel values.

Abstract: A method is described for filtering compressed images represented in the discrete-cosine-transform (DCT) domain. The filter includes three sparse, vertical submatrices which are sparse versions of the vertical filter components (VFCs) of a desired filter function that have been combined in such a way as to eliminate many of the non-zero elements. The filter also includes three sparse, horizontal transpose submatrices, which, like the vertical submatrices, are sparse versions of the horizontal filter components of the filter function. The sparseness of these sparse submatrices yields a significant reduction in the number of computations required to filter the image in the DCT domain. To take advantage of this discovery, the input DCT data blocks are "butterflied" to retain the relationship between the input data blocks and the filtered output data blocks as a function of these sparse submatrices.

Abstract: A system and method for filtering edge points in an edge image represented by an array of edge image coordinates each having an edge point magnitude. An edge map array is formed of edge map coordinates each assigned one of three edge indicator values indicative of the relationship between the corresponding edge image coordinate edge point magnitude and two preselected edge magnitude thresholds. An output edge point array is formed of output edge point coordinates to indicate those edge image coordinates and corresponding object image pixels that are validated by the system as being associated with likely object edge points. This is accomplished by constructing a first address stack to track memory addresses at which edge map coordinate values are stored and constructing a second address stack to track memory addresses at which output edge point coordinate values are stored as the output edge point array is constructed.

Abstract: In an image segmentation system that processes image objects by digital filtration, a digital filter is defined. The digital filter includes a neighborhood operator for processing intensity values of neighborhoods of pixels in a pixel array. A first pixel array is received defining a pixelated image including one or more objects and a background and a second pixel array is received that defines a reference image. The reference image includes at least one object included in the pixelated image in a background. In the reference image, pixels included in the at least one object are distinguished from pixels included in the background by a predetermined amount of contrast. Pixels of the first and second images are compared to determine a merit value; the merit value is used to compute neighborhood operator values; and, the neighborhood operator is applied to images in order to create or enhance contrast between objects and background in the images.

Abstract: Digital image processing method for local determination of the center and the width of objects in the form of contrasting bands on a background. A digital image processing method, for representation of objects in the form of contrasting bands of substantially uniform intensity on a substantially uniform background, includes a step for the identification of pixels situated on the central lines of the objects, which step is referred to as a "tracking" step. This method is characterized in that the step includes a first filtering operation which is executed by applying, to each image, a series of N lozenge-type-bidimensional, selective, recursive low-pass filters having respective ones of the principal directions angulary spaced apart 180.degree./N in order to determine the direction of each band-shaped object segment as that in which the response of one of the filters is maximum.

Abstract: There is provided a digital processor that includes a recursive filter having means for using fixed point arithmetic for performing division. The recursive filter includes means for saving a remainder after each division and multiplication operation and for adding the remainder to a dividend in the subsequent division operation.

Abstract: A method of generating a threshold array made up of a plurality of dot profiles, each of which is made up of a plurality of black or white pixels, certain of the pixels in certain of the dot profiles being constrained to be either black or white.

Abstract: In a noise reduction filter having a filter coupled to receive a plurality of input signal samples (.smallcircle.,.sym.) and furnishing noise-reduced signal samples, and a delay circuit coupled to the output of the filter and which furnishes a plurality of delayed noise reduced signal samples (X) to a further input of the filter, the samples (Pn.sub.1 . . . Pn.sub.n) applied to the filter are not directly neighboring samples.

Abstract: The present invention is directed to an apparatus and method for converting a noncausal, two dimensional signal representative of a digitized image into an equivalent data format that can be filtered by recursive filters. The first step is to estimate an optimal set of parameters by: generating data representative of a potential matrix which represents the signal for a given set of parameters; filtering the potential matrix to arrive at a statistically equivalent recursive data format; inputting white noise to the recursive data format to generate k samples of the signal; obtaining an average value for the correlation {.chi..sub..tau. }; generating data representative of a gradient of a likelihood function; using that data to minimize the likelihood function; comparing the arrived at set of parameters to a previously arrived at set of parameters to determine whether the difference therebetween is within a desired tolerance; and repeating the previous steps until an optimal set of parameters is estimated.

Abstract: A system for digitally trapping color images on a pixel-by-pixel is employed, whereby for each cyan, yellow, magenta and black color separation, an object-oriented trapping process is carried out. After each object is categorized, the original image is separated into a first copy and a second copy. Edge blurring is performed on the edges of the first copy of the original image; masking of a border region is completed on the second copy of the original image according to a laplacian filter, a difference recursive filter or other method. A merged image is created by combining the blurred edge first copy of the image with the mask bordered second copy of the original image; the mask is thereafter removed from the merged image.