Abstract: An arithmetic decoding apparatus is provided that carries out complete pipeline processing. Fluctuations in the pipeline caused by occurrence of the normalization are resolved by using a future-predicted Qe memory. In coding multi-valued images, common contexts are generated without distinguishing between AC and DC components of DCT coefficients.

Abstract: A method and apparatus for decoding information using late contexts is described.

Abstract: A method and system for image coding, wherein an image is divided into a plurality of blocks for scanning. The pixels values in the scanned block are represented by a plurality of level-run value pairs, wherein the level value is indicative of a non-zero pixel value and the run value is indicative of the number of consecutive zero pixel values preceding the non-zero pixel value. A plurality of contexts indicative of the level-run value pairs are conveyed to a decoder for allowing the decoder to reconstruct the image based on the contexts. The assignment of the contexts is also based on the level value of a preceding level-run pair. Additionally, instead of an end-of-block symbol, the number of non-zero coefficients is provided to the decoder prior to conveying the contexts thereto.

Abstract: This invention has as its object to attain efficient encoding/decoding even when the processing time, memory, arithmetic cost, and the like of an apparatus are limited. Encoded image data is input to an image processing apparatus (1) to obtain transform coefficients of subbands. The transform coefficients required to decode an image from its head position line by line are encoded by Golomb coding using one line of a subband as a unit to generate a code sequence, which is output to an image output apparatus (2). The image output apparatus (2) reconstructs an image by decoding the Golomb encoded data, dequantizing the coefficients, and computing the inverse discrete wavelet transforms of the coefficients, and outputs the reconstructed image.

Abstract: A method of compressing a stream of pixel data relative a two-dimensional object, pixels of which are scanned by rows from a source device to a receiver device, includes defining an extended context window to include a pair of pixels following a last encoded pixel on the row being scanned and the respective triplets of neighboring pixels belonging to the preceding row. The method includes defining a first distinct context array of pixels of the extended context window for the pixel of the pair immediately following the last encoded pixel, and a second context array of pixels of the extended context window for the other pixel of the pair. An extended context value relative to each pixel of the pair is calculated, and the extended context value relative to a first pixel immediately following the last encoded pixel is compared with an extended threshold.

Abstract: An arithmetic encoder is provided for converting an event sequence comprised of a plurality of events to an information sequence comprised of at least one information piece, and includes a core engine for receiving an event of the event sequence, and a probability estimate from a probability estimator, and generating zero or more pieces of the information sequence responsive to the received event and the probability estimate by bounding the ratio of events to information pieces. An arithmetic encoder is provided that is capable of constraining a number of events in at least one event sequence as a function of the number of generated information pieces in at least one information sequence.

Abstract: Images are to be efficiently and easily encoded while suppressing block distortion and pseudo-contour generation. A quantization characteristics determining unit receives pixel values from a pixel value input unit, measures the length S of the consecutive occurrence of the same pixel values in connection with a pixel to be encoded and the pixel value differences D, and determines quantization characteristics n with reference to the result of sensory evaluation. A quantization/inverse quantization unit quantizes pixel values to be inputted with the quantization characteristics n, and further inverse quantizes them to reduce the number of gray-scale levels. The output pixel values of the quantization/inverse quantization unit are encoded and outputted by an entropy encoding unit.

Abstract: A Simple Inter Color Lossless Image Coder (SICLIC) for the compression of colored images is provided. The color image is treated as several interlaced gray level images that correspond to respective distinct color planes. The compression scenario utilizes three main steps, such as selection of the predictor, context forming with bias cancellation and coding. SICLIC implements predictors, context forming and encoder techniques that exploit the intra- and inter-color plane correlations in an effective and relatively computationally inexpensive manner. The predictor is selected on the basis of the right selection of the contribution of each color plane between the intra- and inter-plane predictors obtained as a weight average of contribution from different color planes. SICLIC processes the image in two modes—regular mode and run mode. A special care is taken to ensure a proper treatment of joint runs, which occur simultaneously in all color planes.

Abstract: In a renormalization processing device of MQ-CODER, the value of an augend register A is calculated by a shift quantity calculating unit without performing loop processing, and the number of left shifts SHIFT_A of A up to the end of renormalization processing is calculated. The renormalization processing device judges whether byteout processing or bytein processing occurs or not, on the basis of the positive or negative sign of (SHIFT_A-CT) and the value of CT. When byteout/bytein processing occurs, the values of a code register C and a free byte counter CT that are immediately before the occurrence of processing are found. When byteout/bytein processing does not occur, the values of C and CT that are after the end of normalization processing are found. If the value of (SHIFT_A-CT) is a positive value after byteout/bytein processing, this value is substituted in SHIFT_A and renormalization processing is performed again.

Abstract: An orthogonal transform such as a DCT is carried out for image data D5 of an image in blocks obtained by dividing a frame image, the image data D5 being represented by spatial coordinates (Step S102), and a plurality of orthogonal transform coefficients D6 as image data represented by spatial frequencies are generated. Then, the orthogonal transform coefficients D6 undergo arithmetic coding, and thus coded data D7 is generated (S103). Subsequently, in the arithmetic coding of the orthogonal transform coefficients, data characteristics of the orthogonal transform coefficients to be coded, which depend on the spatial frequencies, are considered, and a probability table is switched for a predetermined orthogonal transform coefficient, and thus the arithmetic coding is carried out.

Abstract: Orthogonal transform coefficients D6, which are image data of a coded object, are generated by performing predetermined data transform operations on frame image D1 (Step S100), and coded data D7 is generated (S103) by subjecting the orthogonal transform coefficients D6 to arithmetic coding using a predetermined probability table. Then, in variable-length coding for generating the coded data D7, it is set whether or not a probability table is initialized at the slice layer, and a flag indicating the presence of the initialization is added to a header of a predetermined layer. Thus, the image coding method, image decoding method, image coding apparatus, image decoding apparatus, program, computer data signal, and image transmission system, which are capable of enhancing data compression efficiency by coded data in a manner that a probability table is suitably set over the entire coded data, are realized.

Abstract: A method and apparatus for compressing facsimile documents based on arithmetic coding. A combination of one-dimensional and two-dimensional arithmetic coding is employed to ensure that the effect of a transmission error is not propagated to the whole document. Appropriate contexts for the probabilistic models associated with arithmetic coding for one and two dimensional cases are presented. An error detection scheme to identify the presence of transmission errors is also presented.

Abstract: The invention provides a plurality of compression schemes that provide improved compression ratios. An exemplary embodiment compresses each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. Another exemplary embodiment compresses each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding.

Abstract: The invention provides for the application of a plurality of compression schemes to data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.

Abstract: JPEG (Joint Photographic Experts Group) images are encoded and decoded as fast as possible for a variety of disparate applications. A novel structure stores the 8×8 Discrete Cosine Transform (DCT) blocks after entropy decoding in a JPEG decoder or after the Forward Discrete Cosine Transform (FDCT) in the JPEG encoder to use as an intermediate format between transform processes. The format was chosen to speed up the entropy decode and encode processes and is based on the information needed for the JPEG Huffman entropy coding, but lends itself to fast execution of other DCT based transforms, including arithmetic entropy coding.

Abstract: An image coding apparatus including a blocking unit for blocking an image signal having plural pixel values corresponding to a single image display region into blocks each comprising a number of pixels, and outputting, block by block, the number of pixel values constituting the image signal in each block; pixel value replacing device for replacing a pixel value of an uncoded pixel among peripheral pixels near a target pixel, with a pseudo pixel value that is obtained from a pixel value of a coded pixel among the peripheral pixels based on a rule; and an encoder for receiving the image signal comprising plural pixel values corresponding to each block, performing, for each block, a coding process in which the respective pixel values are successively coded based on the pixel value of the coded pixel and the pseudo pixel value of the uncoded pixel, and outputting an coded image signal.

Abstract: A data coding system is provided for coding an uncompressed data and decoding the coded data. The data coding system comprises a position coding system for defining a context based upon a position of a most significant bit in the uncompressed data and a context value, an encoder for encoding the context to generate an encoded context and compiling the uncompressed data based on the encoded context and remaining bits of the uncompressed data to generate a coded data, and a decoder for decoding the coded data to generate a decoded data.

Abstract: An arithmetic decoding apparatus is provided that carries out complete pipeline processing. Fluctuations in the pipeline caused by occurrence of the normalization are resolved by using a future-predicted Qe memory. In coding multi-valued images, common contexts are generated without distinguishing between AC and DC components of DCT coefficients.

Abstract: A shape information coder divides the pixels in the shape information into subsets representing different subsamplings of the shape information. Each pixel in each subset is coded with reference to a context which may be derived from reference pixels in more than one of the subsets. The context preferably includes reference pixels located on all sides of the pixel being coded, which leads to efficient coding. The shape information coder may have two or more cascaded stages, each operating as above, with one subset of pixels passed from each stage to be coded in the next stage. The resulting coded shape information is useful in, for example, wavelet coding of pictures.

Abstract: Embedded block entropy coding with optimized truncation is useful for image compression schemes in conjunction, for example, with a Wavelet transform, so as to form a bit-stream which can be stored or transmitted with increased efficiency. In the arithmetic coding phase, several opportunities exist for minimizing complexity and improving compression and computational performance as compared to existing systems. One method involves bypassing the arithmetic coding procedure for certain lower significance bit-planes of each code-block. Then, the raw binary digits from these bit-planes can be interleaved into the arithmetically coded bit-stream. As a result, both the average number of arithmetically coded symbols and the maximum number of coding passes per code-block can be significantly reduced.

Abstract: A decoding LSI adaptable to MPEG4 is provided with a padding means for performing padding on decoded texture data, an arithmetic decoding means for performing arithmetic decoding on coded shape data, and a composition means for compositing a plurality of texture data to generate composite image data. The padding means, the arithmetic decoding means, and the composition means are implemented by hardware circuits, i.e., a padding engine, an arithmetic decoding engine, and a composition engine, respectively. Therefore, the decoding LSI can perform high-speed decoding on a bitstream corresponding to plural objects, such as images, which are compressively coded by the MPEG4 coding method, with reduced cost of the hardware circuits performing the decoding process.

Abstract: An arithmetic coding apparatus for carrying out complete pipeline processing is provided. This arithmetic coding apparatus analyzes an input image, reads image information accurately and performs arithmetic coding at ultra-high speed. Using a future prediction type Qe memory removes disturbance in the pipeline caused by renormalization. The arithmetic coding apparatus also generates a common context when coding multi-valued images without distinguishing between an AC component and DC component of a DCT coefficient. The apparatus is also provided with a circuit for outputting an arithmetic code which is a variable-length code with the length fixed to facilitate editing of a reconstructed image.

Abstract: The present invention provides a high speed MMR compression processing method by reducing the number of times of repeating a process of finding the positions of changing pixels a1, a2, b1, and b2. According to this method, first, a bit string corresponding to pixel data is obtained from an image. Then, data are sequentially fetched from the bit string byte by byte. Subsequently, a search is made of a table that describes the number of consecutive bits that are arranged to the right of and have the same color as each of bits of each byte of all bit patterns represented by bits included in the fetched 1 byte. Then, the number of consecutive bits, which are arranged to the right of and have the same color as each of bits of each of the fetched bytes, is detected according to the bit patterns represented by bits of the fetched byte. Subsequently, a pixel placed at the position corresponding to the number obtained by adding 1 to the detected number of consecutive bits is determined as a color changing pixel.

Abstract: Embedded block entropy coding with optimized truncation is useful for image compression schemes in conjunction, for example, with a Wavelet transform, so as to form a bit-stream which can be stored or transmitted with increased efficiency. In the arithmetic coding phase, several opportunities exist for minimizing complexity and improving compression and computational performance as compared to existing systems. One method involves bypassing the arithmetic coding procedure for certain lower significance bit-planes of each code-block. Then, the raw binary digits from these bit-planes can be interleaved into the arithmetically coded bit-stream. As a result, both the average number of arithmetically coded symbols and the maximum number of coding passes per code-block can be significantly reduced.

Abstract: For the entropy coding of image data after subjected to orthogonal transforation and quantization, a plurality of entropy coding units are provided in parallel. The plurality of entropy coding units can be operated efficiently and the entropy coding can be executed at high speed.

Abstract: A method and apparatus for performing selective quantization by manipulation of refinement bits is described. In one embodiment, the method comprises performing a refinement coding pass to bit-planes of a code block to create refinement bits and setting refinement bits to the more probable symbol (MPS).

Abstract: A method and apparatus for decoding information using late contexts is described.

Abstract: Systems and methods for performing adaptive filtering are disclosed. The present invention generates probabilities that can be used in an encoder, such as an arithmetic encoder and generates those probabilities in a computationally efficient manner. Probabilities of previously encoded coefficients are employed, effectively, in generating probabilities of the coefficients without regard to directional information. Thus, a large amount of information is adaptively and efficiently used in generating the probabilities. For the coefficients, the probability is computed based at least partly on at least one probability of a previously computed probability of a neighboring coefficient. Then, the coefficients are encoded using those computed probabilities.

Abstract: A rate-distortion optimized embedding (RDE) coder optimizes rate-distortion performance by coding information bits in the order of their R-D slope. RDE allocates the available coding bits first to the information bit with the steepest R-D slope, which indicates the largest distortion decrease per coding bit. The resultant RDE bitstream can be truncated at any point and still maintain an optimal R-D performance. To avoid the overhead of coding order transmission, an expected R-D slope is calculated by both the encoder and the decoder from previous RDE coded bits. A probability estimation table from a QM arithmetic coder allows the R-D slope to be derived using a lookup table operation. The rate-distortion optimised embedding (RDE) coder significantly improves the coding efficiency over a wide range of bit rates.

Abstract: A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.

Abstract: A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.

Abstract: A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.

Abstract: A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.

Abstract: An adaptive difference computing element which consumes less power without any decrease in calculation accuracy includes: a first circuit receiving first and second data with the same bit lengths and each having bits at one and the other ends, determining if a prescribed relation is obtained between a bit string from each bit to the bit at one end of the first data and that of the second data for each bit of the first data and corresponding each bit of the second data, and replacing the each bit of the first data and the corresponding each bit of the second data with same predetermined bit values if the prescribed relation is obtained, and otherwise directly outputting the first and second data; and a subtracter having inputs connected to receive the first and second data from the first circuit, respectively.

Abstract: A compression and decompression system in which a reversible wavelet filter are used to generates coefficients from input data, such as image data. The reversible wavelet filter is an efficient transform implemented with integer arithmetic that has exact reconstruction. The present invention uses the reversible wavelet filter in a lossless system (or lossy system) in which an embedded codestream is generated from the coefficients produced by the filter. An entropy coder performs entropy coding on the embedded codestream to produce the compressed data stream.

Abstract: Embodiments of the present invention relate to deterministic prediction in an image processing system. One aspect relates to an image processing system having a deterministic prediction decode unit for predicting individual pixels of an image based on a predetermined deterministic prediction algorithm. The deterministic prediction decode unit includes a look-up table, organized into four spatial phases, for storing values to be used by the predetermined deterministic prediction algorithm when converting a relatively low resolution image to a relatively higher resolution image. A prediction is made for a target pixel by accessing at least two of the four spatial phases of the look-up table to read at least two possible values of the target pixel. In one embodiment, the value of two target pixels can be provided within a same clock period, thus allowing for the decoding of two spatial phases with each access to the look-up table.

Abstract: The present invention aims to increase an encoding efficiency when the occurrence probability of LPS (less probable symbol) is low. An encoding apparatus has a interval size (A), a interval limit value (C), divides a set interval which is set on a number line, selects a sub-interval corresponding to an occurring symbol, updates the interval size (A) and the interval limit value (C) with a limited precision based on the selected sub-interval size, and encodes a coordinate within the interval. Based on the probability (the occurrence probability of symbol) output from a learning memory, the sub-interval size (LSZ, dLSZ) and the sub-interval limit value are obtained.

Abstract: A quantified symbol stream is sampled, using the quantified symbols prior to the current symbol, to generate a modeling value that characterizes the stream. The modeling value is used to generate, or retrieve, a probability function that provides the probability that the current symbol will be the next symbol in the symbol stream. The probability given by the probability function is then used to select the used to represent the data. The encoded symbol is later decoded using the characteristics of the code, and an identical probability function, to determine the value of the original quantified symbol.

Abstract: An apparatus for pattern matching encoding includes a pattern extracting unit for extracting patterns in input binary or multi-level image data, an accumulating/match-checking unit for accumulating each extracted pattern and executing a match-check thereof with patterns that have been accumulated, a line segment checking unit for checking each pixel in the match pattern or the extracted pattern as to which line segment in directions the pixel is positioned on, and an encoding unit for encoding the extracted pattern by selecting a template having an optimum form according to the result of the line segment checking. The codes in pattern matching encoding are reduced, and the efficiency of code transmission and code accumulation is improved.

Abstract: An input image is divided into several tile blocks. Wavelet transform is applied to each tile block. At least one region of the wavelet-trans formed data is appointed as a region of interest. The region to be appointed as the region of interest is located in each tile block and in the vicinity of tile border lines. Coefficient-bit modeling is applied to the transformed data for which the region of interest has been set, thus a bit train being generated specific bits of the bit train are truncated and the truncated bit train is converted into byte codes. A bitstream is generated based on the truncated and byte-code-converted bit train. The region-of-interest appointment may be carried out only when a compression rate for the input image reaches a certain level or higher.

Abstract: A method and system for image coding, wherein an image is divided into a plurality of blocks for scanning. The pixels values in the scanned block are represented by a plurality of level-run value pairs, wherein the level value is indicative of a non-zero pixel value and the run value is indicative of the number of consecutive zero pixel values preceding the non-zero pixel value. A plurality of contexts indicative of the level-run value pairs are conveyed to a decoder for allowing the decoder to reconstruct the image based on the contexts. The assignment of the contexts is also based on the level value of a preceding level-run pair. Additionally, instead of an end-of-block symbol, the number of non-zero coefficients is provided to the decoder prior to conveying the contexts thereto.

Abstract: A method and apparatus for performing block sequential processing is described. In one embodiment, the apparatus comprises a determine pass logic, selection logic, next coefficient logic and control. The determine pass logic has inputs coupled to receive significance state information for a region, a pass bit for each coefficient in a subset of the region, and a current pass indication. In response to these inputs, the determine pass logic generates pass indications to indicate a pass for each coefficient in the subset of the region. The selection logic has inputs coupled to signals output from the determine pass logic and the current pass indication and, in response to these inputs, generates output indications associated with one pass of either the significance propagation, refinement, and cleanup passes. The next coefficient logic is coupled to the selection logic and indicates the next coefficient in the current pass in response to the output indications from selection logic.

Abstract: The invention provides a plurality of compression schemes that provide improved compression ratios. An exemplary embodiment compresses each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. Another exemplary embodiment compresses each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding.

Abstract: A coding method and a coding apparatus for bi-level document image which makes a high speed coding processing possible is provided. In the coding apparatus, an image reading processing section provides an image data reading means which reads bi-level image data from a RAM, a CX generating means which generates CX using image data in a line memory and a CX counting means which counts the number of appearance times of CX based on the CX generated by the CX generating means and the inputted bi-level image data. In the coding apparatus, a coding processing section provides a coding processing deciding means which decides to implement either of two kinds of coding processing, a normal coding means which implements a normal coding processing implementing a conventional JBIG algorithm and a high speed coding means which implements a high speed coding processing using the counted values.

Abstract: An image signal processing device enables renewal of probability presumption information to be processed in high speed using logical circuit. A transition state renewal part 101 implements maintenance/renewal of status (‘ST’) value corresponding to respective contexts (‘CX’) and more probability symbol (‘MPS’) value of the ‘CX’. An ‘A’-register operation part 102 implements subtraction between value of ‘A’-register and occurrence probability (‘LSZ’) of low probability symbol (‘LPS’), shift of the ‘A’-register. A probability transition table 103 outputs corresponding ‘LSZ’, next objective of transition (‘NMPS’) in the case of ‘MPS’, next objective of transition (‘NLPS’) when ‘PIX’ is ‘LPS’, and value of occurrence of inversion of ‘MPS’ value (‘SWTCH’) in answer to value of ‘ST’ inputted therein.

Abstract: A dictionary in which a character train serving as a processing unit upon compression has been registered is stored into a character train dictionary storing unit. In a character train comparing unit, the registration character train in the character train dictionary storing unit and a partial character train in non-compression data are compared, thereby detecting the coincident partial character train. A code output unit allocates a predetermined code every partial character train detected by the character train comparing unit and outputs. The character train dictionary storing unit allocates character train codes of a fixed length of 17 bits to about 130,000 words and substantially compresses a data amount to the half or less irrespective of an amount of document data.

Abstract: The invention improves the refresh rate and minimizes the memory for display when reproducing a color image. A color image encoding device has a creation device which counts the number of colors used in color image data and creates a global palette which lists corresponding indexes when the number of colors is a specified value or less, a block division device which divides the color image data into a plurality of blocks, a local palette creation device which creates a local palette which lists indexes in the global palette when the number of colors in a block is less than the number of colors in the global palette, and a color index assigning device which assigns the indexes in the global palette to the input pixels when the number of colors is the same as the number of colors in the global palette, and assigns the indexes in the local palette to the input pixels when the numbers of colors is different from the number of colors in the global palette.

Abstract: A hardware context vector codec/generator which can be used in the block coder of a discrete wavelet transform (DWT) codec. The context vector codec/generator consists mostly of three columns of context vector registers where the context vectors move in parallel from column to column while the bits in the context vectors are modified by digital logic gates placed before each column. The digital logic gates are controlled by the results of the block coder scanning quantized wavelet coefficients. The preferred embodiment is used in a JPEG2000 codec.

Abstract: An image coding apparatus according to the present invention comprises, as shown in FIG.

Abstract: The invention provides for the application of a plurality of compression schemes to data such that improved compression ratios are achieved. A first embodiment provides for compression of each pixel by one of a plurality of different entropy-based compression schemes based upon a probability cost analysis. A second embodiment provides for compression of each pixel based on a hybrid context formed using a plurality of compression schemes for improved probability determination, and thus improved entropy encoding. In embodiments of the invention, a context compression scheme similar to JBIG is applied, as well as an inverse scheme. The context scheme forms a statistical context from a concatenated sequence of previous pixel values. The inverse scheme provides a gray value estimation method based upon previous pixel values and respective threshold values.