Patent ID: 8891621

Claim:
An image coding apparatus that codes a frame of a moving image in units of blocks, comprising: an intraframe prediction unit that generates, for an input moving image target block, a first prediction image block from within a same frame as said target block; an interframe prediction unit that generates, for said target block, a second prediction image block from within a frame different from that of said target block; a selection unit that selects one of either said intraframe prediction unit or said interframe prediction unit in accordance with a predetermined evaluation method; an image high-frequency component extraction unit that extracts a high-frequency component of said target block; an N-ary image conversion unit that reduces a number of gradations of said high-frequency component of said target block to generate an N-arized target block, where N is an integer equal to or greater than 2; and a storage unit that stores output of said N-ary image conversion unit, said interframe prediction unit comprising: a motion detection unit that detects motion of said N-arized target block using output of said N-ary image conversion unit and output from said storage unit; and a prediction image generation unit that generates said second prediction block based on detection results detected by said motion detection unit.