Abstract: A data processor in an image coding apparatus includes a zero detecting circuit for determining if the quantized AC coefficients are zero or not; a counter, that is reset periodically, for counting the quantized AC coefficients that are not zero; a comparator for comparing the count of the counter and a first reference value, and outputting an AC coefficient eliminating signal when the count exceeds the first reference value; and a first logic circuit for forcibly replacing the quantized AC coefficients with zero based on the AC coefficient eliminating signal so that the volume of data of the quantized AC coefficients that are not zero is reduced. The image coding apparatus cuts off some portions for the images having a large volume of codings, and keeps the volume of data below a predetermined maximum.

Abstract: The present invention provides a method for compressing image data. The method first detects a pattern in a first subset of the image data, where the second subset being collocated to a second subset. If no pattern is detected, then a text mode context model is selected. If a pattern is detected, then the period of the pattern is detected and a pattern mode context model is selected. The pattern mode context model has a width directly related to the period of the pattern detected. An arithmetic compressor compresses the second subset using the selected context model.

Abstract: A gray edge component and RGB color components of each pixel in an original image are generated. Saturation of each pixel in the original image is evaluated, and a mixing ratio is determined according to the saturation. Mixed edge components are generated for each pixel by mixing the gray edge component and the respective RGB edge components in the mixing ratio determined. The mixed RGB edge components are added to the RGB components of each pixel in the original image, respectively, to output a sharpened image. Apart from the mixing ratio determined from saturation of each pixel, a common fixed mixing ratio may be designated by the operator for application to all pixels.

Abstract: A method or system for structuring an image which corresponds to an original array of pixels, as a forward discrete even cosine transform (DCT) pyramid having a predetermined number of levels where each level is associated with a different DCT frequency band, includes, respectively, the steps or functionality of: partitioning the original array into blocks of overlapped pixels; taking a DCT of each block of overlapped pixels to generate blocks of first level DCT coefficients forming a first level of the DCT pyramid; storing the first level of the DCT pyramid; selecting and storing at least one of the first level DCT coefficients of each block of first level DCT coefficients into a first temporary array; partitioning the first temporary array into blocks of overlapped coefficients; and taking a DCT of each block of overlapped coefficients of the first temporary array to generate blocks of second level DCT coefficients forming a second level of the DCT pyramid.

Abstract: A method is disclosed for encoding and decoding an input signal representative of video or audio information. A form of the encoding includes the following steps: processing the input signal to produce a sequence of vectors representative of the input signal; implementing a lattice vector quantization procedure on individual vectors of the sequence to identify a lattice point of a lattice that is closest to the individual vector and to obtain an index value representative of a labelling of the identified lattice point, the lattice vector quantization procedure including a multi-level allocation of groups of reserved indices, and selection of the index value for the individual vector within a group of reserved indices. The index signals representative of the index values are stored and then recovered for decoding, or transmitted before decoding. The decoding is operative to obtain a recovered sequence of vectors, and the sequence of vectors can be processed to produce an output signal.

Abstract: In image compression utilizing wavelet conversion for dividing an image of one screen into subbands through multiple steps, subband data of a higher frequency is predicted from subband data of a lower frequency, subtraction is carried out between data obtained by the prediction and an actual higher-frequency subband coefficient at the same position as that for the predicted data to provide a difference, and only the difference is coded. By coding only the difference in this manner, a high compression ratio can be realized.

Abstract: A system and method generates a histogram of a scanned image by determining a number of pixels of the image to be scanned to generate the histogram. It is then determined whether the determined number of pixels is less than or equal to a capacity of a histogram buffer. The image is scanned to generate pixels having grey values associated therewith and a portion of the generated pixels is stored in the histogram buffer if it is determined that the number of pixels exceeds the capacity of the histogram buffer, thereby generating a histogram of the image.

Abstract: The present invention is a method and apparatus for the processing of images that have been compressed using a discrete cosine transform operation, and particularly JPEG compressed images. In a preferred embodiment, the rotation of image blocks is accomplished by sign inversion and transposition operations to accomplish intrablock operations. Subsequently, one of a number of alternative methods is employed to accomplish the same image processing on an interblock level, thereby enabling the rotation or mirroring of compressed images. The two stage process allows the use of either a standardized JPEG system with enhancements or a hybrid processing method, thereby accomplishing the image processing in conjunction with compression or decompression operations and minimizing the need for large memory buffers to accomplish the image processing.

Abstract: The present invention looks for large regions of white or black pixels. In those regions, it is very likely the next few pixels will continue to be the same all white/black value. The present invention replaces the actual encoding of those pixels with whether or not the multi-bit jump was a success. If the jump was unsuccessful then each of the bits unsuccessfully jumped over is encoded using a predefined location in the probability table.

Abstract: A method and apparatus for segmenting image data into windows and for classifying the windows as typical image types includes making two passes through the image data. The method includes a step of making a first pass through the image data to identify windows and to record the beginning points and image types of each of the windows, and a step of making a second pass through the image data to label each of the pixels as a particular image type. The invention also includes a macro-detection method and apparatus for separating a scanline of image data into edges and image runs and for classifying each of the edges and image runs as standard image types. In the macro-detection method, image runs and edges are classified based on micro-detection results and based on image types of adjacent image runs.

Abstract: A system generates image background and black threshold grey values associated with an image. The system includes a histogram buffer and a peak and valley detection circuit, operatively connected to the histogram buffer, to determine a first grey value having a peak frequency associated with a background, a second grey value having a peak frequency associated with a black threshold, and a third grey value having a minimum frequency associated with a histogram of the image. A quarter peak detection circuit, operatively connected to the histogram buffer, determines a fourth grey value having a frequency equal to one quarter of the peak frequency associated with the first grey value and a fifth grey value having a frequency equal to one quarter of the peak frequency associated with the second grey value.

Abstract: A circuit it for deciding classes resulting from 8.times.8 DCT or 2.times.4.times.8 DCT blocks includes a block forming circuit for converting a digital video signal into a predetermined block structure, a mode deciding section for detecting still/motion of the digital video signal block to generate a mode signal, a DCT section for selectively performing the 8.times.8 DCT or 2.times.4.times.8 DCT upon the block supplied from the block forming circuit according to the mode signal of the mode deciding section, a controlling section for controlling DCT data coefficients output according to the mode signal from mode deciding section, a scanning section for zig-zag scanning data in an 8.times.8 activity detecting pattern upon the output of the 8.times.8 DCT block from the DCT section and zig-zag scanning data in a 2.times.4.times.8 activity detecting pattern upon the output of the 2.times.4.times.

Abstract: A specific color field recognition apparatus and method are disclosed. A mechanism fetches a first image including a specific color and a second image with the specific color eliminated therefrom by picking up an image of an object having a specific color field to be recognized. A device produces a first density histogram and a second density histogram representing the number of pixels for each tone with respect to the first image and the second image, respectively.

Abstract: A method for controlling inking during the printing process, in particular during the production run, in a printing press, the printing press having an imaging device coupled to a computing device operative for collecting image color measurement data from the imaging device, and numerically processing the image data, and in which color measurement data are obtained from printed images produced on an continuous basis, these data being used for control or regulation to influence image inking if a predetermined image color tolerance is exceeded, the method which comprises the steps of collecting the image color measurement data, over time using the image color measurement data for computing a color trend estimate; evaluating the color trend estimate and performing a corrective control of the inking if the color trend estimate data indicate that image coloring will move outside the allowable image color tolerance.

Abstract: A method and system generates a histogram from a scanned image by creating a sample window defined by a number of scanlines to be sampled, a number of leading scanlines to be skipped in a slowscan direction before sampling, a number of leading pixels to skip in a fastscan direction before sampling begins, and a number of pixels within a scantine to be sampled. It is then determined if a number of pixels in the sample window is greater than a capacity of a histogram buffer. If it is determined that the number of pixels in the sample window is greater than the capacity of the histogram buffer subsample windows are created within the sample window.

Abstract: A method of extracting the contour of an object having two lateral edges, for example a road, from a digitized photographic image using an automatic active contour propagation process, comprises the steps of entering first and second initial contours near respective lateral edges of the object in the image. The first initial contour is propagated by means of a first automatic active contour propagation process and the second initial contour is propagated by means of a second active contour propagation process. Each propagation process uses, firstly, an energy model including a term relating to elastic coupling forces between paired points of the first and the second initial contours and, secondly, a direction of prolongation of the active contour defined as an average of two prolongation directions determined for the first and the second active contours, respectively.

Abstract: Upon gradation converting input m-bit image information into n-bit image information (m and n are integers; m>n), random numbers, the maximum values of which are changed in accordance with the input values of the m-bit image information, are generated at periods of two or more pixels, and the random numbers are selectively output while switching their signs to positive/negative within the period of two or more pixels. The output signal values and the input values of the m-bit image information are added to each other, and the sum signal values are converted into n-values by a density preservation type quantization method. With this control, the problems of sweeping, texture, and the like of the conventional density preservation type quantization method can be solved without emphasizing the granularity of an image.

Abstract: A method and apparatus for recognition of objects such as faces in images using signal compression techniques (i.e., coding techniques) in which a portion of the image which includes the object to be recognized (e.g., the face) is coded, and the resultant coded data is matched against previously coded and stored training data which makes up a known object database. A given object in an input image signal is matched to one of a plurality of known objects stored in a database, wherein the stored representation of each of the known objects comprises a codebook generated based on training image signals comprising the known object. A first illustrative embodiment comprises the steps of decomposing the given object into blocks; performing a plurality of encodings of the given object, each encoding comprising coding the object with use of one of the codebooks; determining a coding error for each encoding; and matching the given object to one of the known objects based on the coding errors.

Abstract: A method and system for detecting transitional markers such as uniform images in a digital video signal made up of a series of video images is disclosed. One aspect of the invention is a method for detecting uniform fields. The method comprises segmenting a plurality of the video images into a number of cells, each cell comprising a number of pixels, each pixel associated with an intensity value representing the intensity of the pixel. Then, a plurality of cell contrast vectors each associated with one of the segmented video images is generated. Each element of the cell contrast vector is associated with one of the cells of the video image and comprises the standard deviation of the pixel intensity values for the pixels in that cell. A uniform image is detected for a video image in response to the cell contrast vector for that image.

Abstract: Blocking means subjects pixel information of an original sample surface to blocking, a DCT circuit transforms the blocks of input data, a quantizer quantizes the DCT-treated data, a VLC circuit subjects the quantized data to variable-length coding, and a measuring circuit measures the code length based on the quantized data. Variable-length coded data or input sample data is selected in accordance with an output from the measuring circuit so that when the variable-length code content after entropy coding is greater than the data content of unit input sample surface, the input sample data itself, instead of the variable-length coded data, may used as data to be compressed, whereby the average code content is reduced.