Patent ID: 8290286
Filing Date: 2012-10-16
Classification: G06T,H04N

Abstract:
1. A decoding apparatus for decoding a coded block image, the coded block image being obtained by coding transform coefficients included in a block which show spatial frequency components, the transform coefficients being generated by transforming the block image, the apparatus comprising: a memory; a reading unit operable to obtain a total number of non-zero coefficients included in an above block located above a current block to be decoded and a total number of non-zero coefficients included in a left block located to the left of the current block to be decoded, by referring to information, previously stored in the memory, representing the total number of non-zero coefficients included in the above block and information, previously stored in the memory, representing the total number of non-zero coefficients included in the left block, wherein each non-zero coefficient is a transform coefficient having a level value other than “0”; a predictive value determining unit operable to determine a predictive value of a total number of non-zero coefficients included in the current block to be decoded based on the obtained total number of non-zero coefficients included in the above block and the obtained total number of non-zero coefficients included in the left block; a code table selecting unit operable to select a variable length code table based on the determined predictive value of the total number of non-zero coefficients included in the current block; a decoding unit operable to decode the coded block image by using the selected variable length code table, to obtain an actual value of the total number of non-zero coefficients included in the current block; and a storing unit operable to store the actual value of the total number of non-zero coefficients included in the current block, as information representing the total number of non-zero coefficients, in the memory.