IMAGE CODING DEVICE AND IMAGE DECODING DEVICE AND CONTROL METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a technology which is based on a technology for extracting a pixel value occurring in a block and then coding the identification information indicating whether the pixel position is the one having the extracted pixel value, and which yet performs coding still more efficiently.SOLUTION: A blocking unit accepts image data in block units composed of M pixels as its input. An extraction unit analyzes the inside of an input block of interest and extracts a pixel value occurring in it, as well as generates for each extracted pixel value identification information composed of identification data indicating whether the pixel position is the one having that pixel value. A data reduction unit reduces the identification data in the generated identification information. A coding unit 104 codes each identification information which have had their identification data reduced. A pack unit 105 packs the extracted pixel value and the coded identification information together and outputs it as the coded data of the block of interest.