ENTROPY CODING METHOD USING AN INDEX MAPPING TABLE, AND IMAGE-ENCODING/DECODING APPARATUS AND METHOD USING SAID ENTROPY CODING METHOD
First Claim
1. An image decoding method, comprising:
- mapping a received codeword to a specific code number with reference to an inverse codeword mapping table and calculating the mapped code number in a form of a table index; and
updating an inverse index mapping table based on at least one of a cumulative number of times that the specific code number has been generated, a consecutive number of times that the specific code number has been generated, coding/decoding information about a peripheral block, and critical value information for updating the inverse index mapping table.
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Abstract
Disclosed is an entropy coding method using an index mapping table, and an apparatus using the method. An imagedecoding method comprises: a step of mapping an inputted codeword to a code number with reference to an inverse codeword mapping table, and calculating the mapped code number in a table index; and a step of updating the inverse mapping table based on the accumulated number of occurrences of the code number, the number of sequential occurrences of the code number, neighbor block encoding/decoding information, and/or threshold value information for updating the inverse index mapping table. According to the present invention, an index mapping table is realigned based on a certain condition, thereby improving encoding/decoding efficiency.
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Citations
18 Claims
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1. An image decoding method, comprising:
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mapping a received codeword to a specific code number with reference to an inverse codeword mapping table and calculating the mapped code number in a form of a table index; and updating an inverse index mapping table based on at least one of a cumulative number of times that the specific code number has been generated, a consecutive number of times that the specific code number has been generated, coding/decoding information about a peripheral block, and critical value information for updating the inverse index mapping table. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An image decoding apparatus, comprising:
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a table index calculation unit for mapping a received codeword to a code number with reference to an inverse codeword mapping table and calculating the mapped code number in a form of a table index; and an inverse index mapping table calculation unit for updating an inverse index mapping table based on at least one of a cumulative number of times that the code number has been generated, a consecutive number of times that the code number has been generated, coding/decoding information about a peripheral block, and critical value information for updating the inverse index mapping table.
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Specification