Abstract: An image coding apparatus comprises:

Abstract: Decoding variable length codes having regular bit pattern prefixes enables faster decoding of variable length codes, especially in systems that provide bit or bit mask search capabilities. An embodiment of the present invention determines a code prefix type, and calculates a length of the code prefix. A first data structure may be provided to associate the maximal number of bits in a variable length code with the length of the code prefix, and to locate further decoding data in accordance with the prefix length and type. A bit stream may be read according to the maximal length obtained. An additional data structure may be provided to retrieve a decoded value and the actual length of a variable length code being decoded. This data structure may be indexed with the value of the bit combination read from the bit stream. In case the actual length of the variable length code is less than the maximal length, the excess bits may be returned to the bit stream.

Abstract: A method and device for reducing a compressed image to a target size by reducing the quality of the image by a quality scaling factor. Image statistics inherent to the image are used to compute the size reduction as a function of the quality scaling factor. Using the relationship between the quality and the size of the image, an estimated quality scaling factor is obtained based on the target size in an iterative process until the size reduction corresponding to the estimated quality scaling factor is substantially equal to the target reduction.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

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 fast, memory efficient, lookup table-based system for VLC decoding. Code words are grouped by prefix and recoded to reduce the number of bits that must be matched, thus reducing the memory requirements. General-purpose processor and finite state machine decoder implementations are described.

Abstract: New and improved variable length decoding methods and apparatus. The present invention provides speed performance and efficiency for decoding data by comparing, in parallel, a first plurality of code words of received data with respective values from a code length table. If the compared first plurality of code words are outside of a criterion, a second plurality of code words of received data are compared with respective values from the code length table. If one of the code words from one of the first and the second compared plurality of code words meets the criterion, it is determined which one of the code words from the first and the second compared plurality of code words has met the criterion. Once the code word meeting the criterion is determined, its symbol value is provided.

Abstract: The present invention selectively applies one of VLC tables stored in a memory for encoding a coded block pattern of a macroblock according to the number of blocks having an object within the macroblock, the number of blocks obtained using shape information, thereby reducing the amount of data transmitted and increasing coding efficiency. The present invention also selectively applies one of VLD tables stored in a memory for decoding a coded block pattern of a macroblock according to the number of blocks having an object within the macroblock, the number of blocks obtained using shape information.

Abstract: Disclosed is an arrangement for easily and quickly performing variable length coding for a multi-valued image, while estimating coding efficiency. To achieve the above objective, an encoding apparatus, which encodes a plurality of sets of multi-valued image data to produce code having variable lengths based on the multi-valued image data and a parameter k, comprises a bit shift unit for performing bit shifts for each of the multi-valued image data sets a different number of times in accordance with the parameter k and for outputting P sets of data, P accumulation adders for accumulating the P sets of data in correlation with the parameter k, for each of the multi-valued data sets, and comparators for comparing the results obtained by the accumulation adders to determine an optimal parameter k for each of the multi-valued image data sets.

Abstract: The coded block parameters used to code blocks of image samples into structures called macroblocks are compressed more efficiently by exploiting the correlation between chrominance and luminance blocks in each macroblock. In particular, the coded block pattern for chrominance and luminance are combined into a single parameter for the macroblock and jointly coded with a single variable length code. To further enhance coding efficiency, the spatial coherence of coded block patterns can be exploited by using spatial prediction to compute predicted values for coded block pattern parameters.

Abstract: A still image compressing apparatus which constantly maintains the compression rate, and a method therefor are provided The still image compressing apparatus which constantly maintains a compression rate, comprises a luminance and chrominance signal generator which receives R, G and B signals of a still image and generates luminance and chrominance signals, a discrete cosine transformer which divides the image, represented by the luminance and chrominance signals, into square areas of a predetermined size, and decomposes each square area into coefficients for all the frequencies ranging from a mean value to a maximum frequency image component, a regular compression rate quantizer which divides each coefficient by a predetermined quantization step size, where coefficients corresponding to frequencies higher than a reference frequency are divided by the maximum possible step size, and an entropy decoder having a code scheme, which allots short-length codes to values having a high probability of occurrence among

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: The objective of the present invention is to perform fast variable-length coding that is applied for lossless compression and encoding.

Abstract: The present invention relates to an image data reconstructing apparatus for reconstructing an original image by dividing image data into a plurality of blocks each comprising N×N picture elements, performing two-dimensional orthogonal transform on each of the blocks, quantizing and encoding the result of the two-dimensional orthogonal transform, decoding the encoded result, dequantizing and two-dimensional inverse orthogonal transforming the above result, wherein an operation associated with the multiplication is skipped if a multiplication by zero is detected when two-dimensional inverse orthogonal transform is performed. Before performing dequantization, two block volume of buffer is provided before or after performing two-dimensional inverse orthogonal transform for executing a pipeline process.

Abstract: Compression of digital ink is achieved by calculating second order differences between consecutive elements in the digital ink and applying the differences to a Huffman encoder to produce a compressed bitstream. For digital ink that is not highly correlated, compression may be achieved by representing segments of the digital ink by mathematical shapes such as a Bezier curve or orthogonal elements and transmitting the shape instead of the digital ink.

Abstract: A method and apparatus for coding and decoding information is described. In one embodiment, the apparatus comprises a memory and decoding hardware. The memory stores run counts and/or skip counts and the decoding hardware decodes a run count and/or a skip count obtained from the memory during decoding.

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: Provided is a probabilistic statistical data compression/restoration method for variable-length encoding a source character and restoring a variable-length code to a character using the probability of occurrence of the source character which appears following a character string (context) of n characters which immediately precede the source character. When variable-length encoding is performed, a context registration unit successively registers context based upon an entered character without fixing the length (degree) of context, and a compressing encoder selects registered context satisfying a predetermined condition, e.g., registered context for which the frequency of occurrence is greater than a fixed value, as context (encoding context) used in encoding, and variable-length encodes a source character by using this encoding context. A restoration unit restores a code to a character by executing processing which is the reverse of the processing executed by the compressing encoder.

Abstract: A video decoder compliant with the Advanced Television Systems Standard (ATSC) includes circuitry which, when the decoder is operated in a first mode, decodes a Main Profile, High Level (MP@HL) image to produce a high-definition video output signal and decodes a Main Profile, Main Level (MP@ML) signal to produce a standard definition video signal. In addition, when the decoder is operated in a second mode, circuitry is used which generates a standard definition image from the MP@HL signal. The video decoder includes a frequency-domain filter to reduce the resolution of the MP@HL signal when the decoder is operated in the second mode.

Abstract: A signal decoding system performs variable length decoding and inverse quantization at high speed. From a bit stream temporarily held in a bit string buffer, the bit string is parsed as a table address for a lookup table in a table looking-up unit and a table selecting unit. By looking up the table address in the lookup table, variable length decoding is performed simultaneously for a maximum of two codewords. Furthermore, the decoded data is inversely quantized in parallel by using inverse quantizers. The results of inverse quantization are stored at appropriate positions in the block by the block storage unit.

Abstract: Conversion between different codes can be implemented at high speed by a small device. A code input unit inputs a code. A compatible information reference unit refers to compatible information of each compressed symbol before and after code conversion, which then sends out compatible information data to a compressed symbol conversion unit. The compressed symbol conversion unit converts each of the compressed symbols in the input code data to a form adapted to a code to be converted based on the compatible information data, which then sends out converted code data to a converted code output unit.

Abstract: A computer file update or patch process involves building a Patch File. The existing or original file (the OLD file) and the revised file (the NEW file) are input into a Patch Build program. The differences in the OLD file and the NEW file are determined by the Patch Build program, and this information is output by the Patch Build program as a Patch File. The Patch File is distributed, along with a Patch Apply program, to end users so that the OLD file is efficiently converted to the desired, updated NEW file. The OLD file and the Patch File are input by the end user into the Patch Apply program. The Patch Apply program changes, at the bit level, only the portions of the OLD file required to yield the desired file update. By distributing only the Patch File and Patch Apply program to the end users, the desired file update can be implemented by the end user with maximum operational and economic efficiency.

Abstract: To compress images using transition information of adjacent pixels, index transition patterns of two adjacent pixels in the horizontal scanning direction of an image are computed and arranged in order of appearance frequency, then patterns within the upper four appearance frequencies are selected to create a reference table. Then, with reference to the created reference table, image data are encoded. When decoding the encoded data, at first data from both the reference table and the color look-up table is inputted and stored in the table 50 and the color look-up table 53. After this, the first data of the subsequent input data is supplied to both the color look-up table 53 and the delay circuit 51 by changing over the connection of the switch 52. Subsequent data is supplied to the table 50. The table 50 decodes the data to original image data with reference to the data and the output from the delay circuit 51.

Abstract: A sorting device for a variable-length code containing the following parts: a coding part 43 that converts the length value to a first bit column according to its value, a first shifter 44 that converts the first bit column input from said coding part 43 to a second bit column according to the shift parameters, a second shifter 42 that converts the code value to a third bit column according to the shift parameter, and a register 45 that has the second bit column input from said first shifter 44 and the third bit column input from said second shifter 42, and which outputs only the content of the bit at the position of the third bit column corresponding to the position of the bit indicating the prescribed value “1” of the second bit column.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: Disclosed is a method of compressing data contained in variable length or universal variable length code words to be carried in a digital bitstream. The method includes formatting a first set of code words for data and then constructing a second set of code words containing code words from the first set as well as concatenations of code words from the first set. Code words from the second set are to carry data in compressed form in the digital bitstream. One way in which the concatenation is accomplished includes selecting a code word from said first set of code words and applying it as a prefix to itself and to all of the other words in the first set, thereby constructing the second set. The code word selected from the first set for application as a prefix may be the shortest code word of the first set.

Abstract: A video signal processing apparatus processes coded data obtained by compressively coding a digitized video signal. The apparatus includes a specific component removing unit for removing specific components in the coded data. The specific component removing unit has a variable-length decoding unit for subjecting the variable-length coded data to variable-length decoding, an inverse quantization unit for inversely quantizing the processing result of the variable-length decoding unit, by using a first quantization matrix, a quantization unit for quantizing the processing result of the inverse quantization unit, by using a second quantization matrix, and a variable-length coding unit for subjecting the processing result of the quantization unit to variable-length coding. Therefore, the data quantity of the variable-length coded data can be reduced without significantly increasing the circuit scale.

Abstract: A method for encoding a visual object, includes encoding a visual object to obtain compressed coded data, wherein the compressed coded data is obtained through at least one of a plurality of different operations which can be performed on a block by block basis. A descriptor capable of including information of a respective parameter related to the number of times that each of the operations was performed in a unit of blocks is generated, the descriptor associated with a complexity of decoding the compressed coded data. The descriptor is multiplexed with the compressed coded data, wherein the descriptor comprises an identification number identifying a descriptor type, a length field indicating a size of the descriptor, and the parameter.

Abstract: An image file, which typically represents a palette-based image that has been encoded using a first predefined run-length based encoding method, is decoded to produce an image data array. The image data array is divided into blocks; either all the blocks or a majority of the blocks have a predefined fixed size. At least some of the blocks of the image are processed to produce a corresponding re-encoded block. In particular, each such block is processed by applying a plurality of distinct encodings to the block to produce an equal plurality of distinct re-encoded block versions. One of the plurality of distinct re-encoded block versions is selected in accordance with predefined selection criteria for use as the re-encoded block. Each re-encoded block is stored in a distinct data structure, such as a file.

Abstract: A general-purpose processor performs high-speed variable-length decoding. The general-purpose processor includes a video data register for exclusively storing the variable-length code that stores data having a length larger than the maximum length of the variable code to be decoded. The general-purpose processor also includes a data counter register for exclusively storing the length of the data in the video data register which has not been decoded, as well as a pointer register for exclusively storing the address of the variable-length code to be read out next from a bit stream stored in memory. The general-purpose processor also includes an ALU for performing general purpose operations, and decodes the variable-length code stored in the video data register by controlling the video data register, the data counter register, and the pointer register.

Abstract: A method of buffering video data in a video compression system, in which a video bit stream, compressed on the basis of an international standard, is transmitted adaptively to a state of a transmission channel under a digital communication environment where a transmission speed is very low and a bit error generation rate is very high. The video data buffering method comprises the step of performing a discrete orthogonal transform operation with respect to input video data in the unit of blocks and storing the resultant coefficients in the unit of discrete orthogonal transform components.

Abstract: The present invention provides a system, device, computer program product, and method for representing a plurality of electronic ink data points. According to one embodiment, the system includes a first computing device having a writing stylus, a handwriting capture interface, a processing element and a transmitter. The handwriting capture interface captures a plurality of electronic ink data points based upon a position of the writing stylus, while the processing element is capable of determining a derivative of at least the second order of the electronic ink data points. The transmitter transmits data representative of the high-order derivative of the electronic ink data points. The system also includes a second computing device capable of receiving the data. The second computing device includes a processing element for reconstructing the electronic ink data points based upon the high-order derivative and independent of all but one of the electronic ink data points originally captured.

Abstract: A conventional variable-length codebook is converted into a modified codebook in which each symbol is represented by the same number of bits, but at least one symbol can be represented by at least two different code words. Such symbols therefore may be said to have redundant bits, which may then be used to encode other symbols, thereby achieving a degree of data compression. By using fixed-length code words, the positions of code words in the resulting encoded data stream are known a priori. As a result, the encoded data can decoded in parallel. The present invention provides both the data compression advantages of variable-length encoding schemes and the ability to perform parallel decoding processing of fixed-length encoding schemes. The present invention can be embodied in either lossless or lossy implementations.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: Method and apparatus for compressing data representing a set of symbols such that each symbol of the set can be separately accessed and decompressed. Each symbol of the set of symbols is encoded in the form of a two-pair code wherein a first part of the code is common for all encoded symbols and a second part of the code encodes the data representing a symbol. An identifier is given for each symbol for permitting each encoded symbol to be separately accessed and decompressed. The invention is particularly useful for storing large fonts such as a Chinese or Japanese character set.

Abstract: Compression of digital ink is achieved by calculating second order differences between consecutive elements in the digital ink and applying the differences to a Huffman encoder to produce a compressed bitstream. For digital ink that is not highly correlated, compression may be achieved by representing segments of the digital ink by mathematical shapes such as a Bezier curve or orthogonal elements and transmitting the shape instead of the digital ink.

Abstract: An image processing apparatus compresses multi-level images created by a computer or the like at a high compression rate. To achieve this, the image processing apparatus includes an ADCT compression unit for compressing input multilevel image data for every block of data (the blocks having a predetermined size) by an irreversible compression method, and a reversible compression unit for compressing the input multilevel image data for every block by a reversible compression method. Selection between output data from the two compression units on the basis of data having a predetermined level and compressed by the reversible compression unit.

Abstract: An image compression and restoration technique may be used as a substitute for JPEG. In this technique, orthogonal transforms are performed on the original image signals without interpolation, which means it requires less calculation than JPEG standard. Furthermore, the degradation of the image quality can be suppressed. After that quantization, re-ordering and Huffman coding follow. The Huffman coding is also unique in the sense that unlike JPEG, it uses the data from the previous blocks which results in a more simple, less CPU intensive codec technique. Conversely, the compressed data is restored using a procedure reverse to that of the aforementioned compression technique.

Abstract: The coded block parameters used to code blocks of image samples into structures called macroblocks are compressed more efficiently by exploiting the correlation between chrominance and luminance blocks in each macroblock. In particular, the coded block pattern for chrominance and luminance are combined into a single parameter for the macroblock and jointly coded with a single variable length code. To further enhance coding efficiency, the spatial coherence of coded block patterns can be exploited by using spatial prediction to compute predicted values for coded block pattern parameters.

Abstract: A detection circuit detects a slice start code from an input stream. Based on a result of the detection and a frame pulse, a reference macroblock (MB) address generated by a timing generator is sent to an address comparator. The input stream which has been phase-adjusted by a delay circuit is supplied to a variable length decoder (VLD) for decoding a variable length code to detect an MB address. The address comparator compares the reference MB address with the MB address to check the continuity of the MB address. If it is discontinuous, the stream output from the VLD is temporarily interrupted, and a selector selects a replacement data generating circuit in response to a control signal output from the address comparator. The input stream is replaced at a discontinuous macroblock portion with macroblock data which has a correct macroblock address and which is prepared in advance by the replacement data generating circuit.

Abstract: The invention disclosed here is a method for an encoder to encode audiovisual information for transmission to the decoder without any prior knowledge of the computational capabilities of the decoder. A descriptor containing parameters that can be used to estimate the complexity of the decoding process is embedded in the system stream. The encoder also encodes the video information in such a manner that the decoder can choose to ignore some of the information and only decode a subset of the encoded information in order to reduce the computational requirements. This method allows more than one decoder to decode the same bitstream giving different resolutions depending on the computational capability of the decoder.

Abstract: Whether a header information processor quickly enters a program inactive state at the timing when it issues an operation start command of an encoding process for a predetermined processing unit to a variable-length code encoder, or the header information processor enters the program inactive state upon completion of execution steps to be processed is adaptively selected in accordance with the number of execution steps. One memory is shared by the header information processor and variable-length code encoder, and address input permission means for controlling to grant permission of an address input to the memory to one of the header information processor and the variable-length code encoder is provided. The memory is used as a work area of the header information processor, and as a storage area of a variable-length code table which is looked up by the variable-length code encoder.

Abstract: A system and method for performing a coefficient reconstruction in a decoder. The method comprises receiving a transmitted coefficient of a first block. The method also comprises retrieving a former reconstructed value. Additionally, the method comprises executing a first arithmetic operation to generate a reconstructed value of the transmitted coefficient. The first arithmetic operation is performed using the transmitted coefficient and the former reconstructed value. Finally, the method comprises replacing the former reconstructed value with the new reconstructed value.

Abstract: A method and apparatus for manipulating digitized images stored as variable length encoded bitstreams such as JPEG format in a manner that reduces memory and processor resource requirements. A prescan means sequentially decompresses the bitstream to identify the location of encoded pixel image areas. Designated ones of these locations are recorded or stored in a prescan table. After the prescan operation has been performed on the image, image manipulations such as rotating, cropping, and zooming can be performed on a selected portion of the image by directly accessing only the encoded pixel image areas to be manipulated, without the need to sequentially decode and store all the encoded image areas in order to locate the ones of interest.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: The invention disclosed here is a method for an encoder to encode audiovisual information for transmission to the decoder without any prior knowledge of the computational capabilities of the decoder. A descriptor containing parameters that can be used to estimate the complexity of the decoding process is embedded in the system stream. The encoder also encodes the video information in such a manner that the decoder can choose to ignore some of the information and only decode a subset of the encoded information in order to reduce the computational requirements. This method allows more than one decoder to decode the same bitstream giving different resolutions depending on the computational capability of the decoder.

Abstract: The invention disclosed here is a method for an encoder to encode audiovisual information for transmission to the decoder without any prior knowledge of the computational capabilities of the decoder. A descriptor containing parameters that can be used to estimate the complexity of the decoding process is embedded in the system stream. The encoder also encodes the video information in such a manner that the decoder can choose to ignore some of the information and only decode a subset of the encoded information in order to reduce the computational requirements. This method allows more than one decoder to decode the same bitstream giving different resolutions depending on the computational capability of the decoder.

Abstract: A decoding device for Huffman codes, provided with an operation circuit for determining, from a Huffman code to be decode, the code length of the Huffman code and a predetermined code number thereof by calculation, and a conversion circuit for converting the code number into a fixed-length code prior to encoding.

Abstract: In an image coding method of the present invention, after a process such as DCT is performed to digital image data, quantization process is performed, and then, to resultant quantized transform coefficients, variable length coding process is performed with reference to a variable length code table showing how variable length codes are allocated, and in a comparison process between an event derived from the quantized transform coefficients and a reference event included in the variable length code table, transformation process is performed to increase a possibility of performing variable length coding with satisfactory coding efficiency.

Abstract: An image encoding apparatus according to the present invention effectively encodes an image without its degradation, at a low price. A block division circuit 1 receives image data 100, dividing it into several blocks. An orthogonal transformation circuit 2 orthogonally transforms each block of divided image data into transformed coefficients. A code amount control circuit 3 calculates a quantization step value 105 and a quantization number 106, which will restrict the number of coefficients in a macroblock to be quantized, using both the sum of the absolute values of the transformed coefficients of respective blocks and a code amount cumulative value 104 output from a variable-length encoding circuit 6, and then outputs them to a quantization circuit 5. A delay circuit 4 delays the coefficients 102 for the necessary number of clock pulses. The quantization circuit 5 quantizes the delayed coefficients 107, using the quantization step value 105 and the quantization number 106.