IMAGE COMPRESSION APPARATUS AND IMAGE DECOMPRESSION APPARATUS, AND COMPUTER-READABLE RECORDING MEDIUM RECORDED WITH PROGRAM FOR MAKING COMPUTER RUN IMAGE COMPRESSION METHOD AND IMAGE DECOMPRESSION METHOD

摘要

PROBLEM TO BE SOLVED: To efficiently encode an image without causing any color shift in appearance.

SOLUTION: The image compression apparatus compresses color image data comprised of a plurality of blocks. It comprises: a resolution determining and processing section 142 which adaptively determines the resolution on each block when an image is contracted for each component image data of color image data according to a predetermined reference and creates the information about resolution; a data creating and processing section which creates data wherein some blocks are contracted as needed, for each component image data, based on the information about resolution; and a contracted data encoding and processing section and same-size data encoding and processing section for encoding the data created by the data creating and processing section. The resolution determining and processing section 142 determines the resolution on each block according to a degree of impact when each component image data is converted from a first color space of the color image data to a second one which is different from the first one, and then creates the information about resolution.

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