IMAGE CODING METHOD, IMAGE CODING DEVICE, IMAGE DECODING METHOD, IMAGE DECODING DEVICE, AND PROGRAM THEREFOR

摘要

PROBLEM TO BE SOLVED: To solve the problems that an existing technique in BA mode of ALF produces waste in the generated amount of code, that sufficient improvement in picture quality cannot be attained, and that there is a lot of waste in the arithmetic operation of a decoding device.SOLUTION: Instead of classifying edges equally into N stages for all of activity classification, an optimum ClassSet determination unit 205 is given the freedom to switch between a plurality of edge classification techniques (class sets) as variable for each stage of activity classification. Filter processing is applied to blocks of an input image by using a coefficient set corresponding to an edge classification pattern designated by the class set for each stage of activity classification which the optimum ClassSet determination unit 205 has determined. In this way, information indicating which class set has been assigned to each stage of activity classification is encoded as overhead.