Abstract: An coding apparatus includes a number-of-additional-bits calculating means 107 for calculating the number of bits which can be set, as additional bits, at an end of a code sequence in which an information source is entropy-coded on the basis of information about the end of the code sequence, the information being driven from code data which form the code sequence, and an additional bit coding means 108 for setting the additional bits having the number of bits at the end of the code sequence.

Abstract: An image coding apparatus includes: an entropy coding unit for outputting code data based on control information for every coding pass; a rate control information extracting unit for judging both a continuation and an end of the coding pass based on a calculation result of a distortion and a code amount, which are required in a rate control; and a unit for extracting the code data up to the coding end pass based on control information. The rate control information extracting unit includes: calculation units for calculating both a distortion and a code amount produced by coding each of the coding passes; another calculation unit for calculating a slope based on a relationship between the distortion and the code amount, and a coding pass conducting unit for outputting control information based on a slope, a total code amount of all components, and a total code amount of a specific component.

Abstract: An image coding apparatus includes a rate control information extraction means for determining which up to a coding pass in which code block should be coded from the sum of the code amounts of the code blocks, the slope of an RD curve calculated from the distortion difference between a coding distortion at a time of coding each coding pass and a coding distortion at a time of coding a preceding coding pass, and the number of output bytes of the code amount of each coding pass, and the inverse of one of given rate control parameters which are listed in order of decreasing monotonously, and for outputting an end-of-coding pass, and a coded data extraction means for reading coded data including up to coded data corresponding to the end-of-coding pass, for adding the number of coding passes to the coded data, and for outputting them as a code stream.

Abstract: An image coding apparatus includes: an entropy coding unit for outputting code data based on control information for every coding pass; a rate control information extracting unit for judging both a continuation and an end of the coding pass based on a calculation result of a distortion and a code amount, which are required in a rate control; and a unit for extracting the code data up to the coding end pass based on control information. The rate control information extracting unit includes: calculation units for calculating both a distortion and a code amount produced by coding each of the coding passes; another calculation unit for calculating a slope based on a relationship between the distortion and the code amount, and a coding pass conducting unit for outputting control information based on a slope, a total code amount of all components, and a total code amount of a specific component.

Abstract: Provided in an image decoding apparatus including an input unit for inputting a code stream; a low frequency sub-band component decoding unit for decoding a low frequency component; a high frequency sub-band component decoding unit for decoding a high frequency component; a substitute image producing unit for processing the low frequency component decoded image to produce a substitute image; an error detecting unit for detecting an error when a decoding operation is carried out; a timing producing unit for producing a timing signal; a remaining decoding time calculating unit for calculating a remaining decoding time based on both the error detection signal and the timing signal; an output image control unit for controlling to adaptively select an output image based on the error detection signal and the decoding process time signal; and an output image selecting unit for selecting any one of the high frequency component decoded image and the substitute image based on the control operation by the output image c

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: By combining a plurality of encoding methods actively, an encoding efficiency is enhanced. The first encoder encodes a result of determination whether a prediction error is zero or not. The second encoder encodes the prediction error unless the prediction error is zero. The third encoder encodes the prediction error regardless of whether the prediction error is zero or not. The mode determinator determines the encoding mode, and the encoding controller selectively operates the first encoder, the second encoder, and the third encoder according to the encoding mode determined.

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: An encoding/decoding method for predicting appearance probability of an information source symbol, while learning, and for dividing a valid section on a numerical straight line into both a first partial section to which an approximate value of the above-mentioned prediction appearance probability is applied and a second partial section remained in the valid section, to which such an arithmetic code is applied, the arithmetic code setting a partial section corresponding to an appearing symbol as a new valid section, is operated by storing thereinto such a fact that the prediction appearance probability is a specific value; by judging that the prediction appearance probability is equal to the specific value by referring to the relevant specific value; and by correcting an allocation between the first partial section and the second partial section when the judgement operation judges that the prediction appearance probability is equal to the specific value.

Abstract: In an adaptive probability estimation method, an index referring to coding parameters is determined according to occurrence probabilities of symbols from estimated occurrence counts of symbols, thresholds for probability values that determine the probability intervals corresponding to the indexes are set to values that are examined with small operational load, and an index referring to the corresponding occurrence probability is selected without division, using the probability intervals determined by the thresholds for probability values.

Abstract: Encoding efficiency is enhanced by actively combining a plurality of encoding methods. A picture element memory receives and stores picture elements within a predetermined range. A mode determinator selects an encoding mode based upon a reference picture element. A first encoding section and a second encoding section predicts the value of the encoded picture element, determines whether the prediction is correct, and then encodes the value of the encoding picture element based on the determination result and outputs a codeword for the encoding picture element. An encoding controller selectively operates the first encoding section and the second encoding section based upon one of the specific encoding modes and the other encoding mode other than the specific encoding mode selected by the mode determinator.

Abstract: In encoding/decoding methods, as to a symbol of such a probability value equal to power of 1/2, an occupation rate of a valid section is corrected in such a manner that this occupation rate may become the probability value, and partial sections are allocated thereto. As a result, an encoding efficiency is improved.

Abstract: In an adaptive probability estimation method, an index referring to coding parameters is determined according to occurrence probabilities of symbols from estimated occurrence counts of symbols, thresholds for probability values that determine the probability intervals corresponding to the indexes are set to values that are examined with small operational load, and an index referring to the corresponding occurrence probability is selected without division, using the probability intervals determined by the thresholds for probability values.

Abstract: By combining a plurality of encoding methods actively, an encoding efficiency is enhanced. The first encoder encodes a result of determination whether a prediction error is zero or not. The second encoder encodes the prediction error unless the prediction error is zero. The third encoder encodes the prediction error regardless of whether the prediction error is zero or not. The mode determinator determines the encoding mode, and the encoding controller selectively operates the first encoder, the second encoder, and the third encoder according to the encoding mode determined.

Abstract: An adaptive coding method is comprised of: a fourth step (508), (510) for calculating an occurrence frequency of either the more probable symbol (MPS) or the less probable symbol (LPS) with respective to the entered input; a fifth step (511) for comparing an occurrence time accumulated value calculated as the occurrence frequency at the fourth step with a preselected value (threshold value), and for reducing the occurrence time accumulated value by 1/2 in the case that the occurrence time accumulated value reaches the preselected value (threshold value); and a sixth step (513) for defining the more probable symbol (MPS) and the less probable symbol (LPS) in correspondence with a predetermined region on a numerical line with respect to the data signal to thereby output coordinate values on the numerical line as a corded word.

Abstract: An image memory outputs a target encoding pixel and a plurality of reference pixels in the vicinity thereof. A boundary mode determining unit determines a maximum value and a minimum value of the reference pixels, determines an average value of the maximum value and the minimum value, compares the respective reference pixel values with the average value, detects a boundary in the target encoding pixel and the reference pixels based on comparison results, and detects a pixel distribution state of the reference pixels based on the detected boundary. An adaptive predictor calculates a prediction value by performing a calculation based on a function corresponding to the pixel distribution state and the reference pixels. A prediction difference calculating unit determines a difference value between the prediction value and a value of the target encoding pixel.