Patent ID: 8014611

Claim:
An image compression method comprising: a preprocessing step of performing preprocessing on input image data; and a data compressing step of performing a data compression processing on preprocessed image data, wherein said preprocessing step includes: a filtering region dividing step of dividing said input image data into a plurality of filtering regions being units for a filtering processing; a region designating step of discriminating important regions from unimportant regions in said input image data; and a filtering step of performing said filtering processing only on said unimportant regions for each of said filtering regions to attenuate a high frequency component of said input image data, said data compressing step includes: a block region dividing step of dividing said preprocessed image data into a plurality of block regions being units for an orthogonal transform, each shape of which is rectangular; an orthogonal transforming step of performing said orthogonal transform processing said image data for each of said block regions; and a quantizing step of quantizing said image data that has been subjected to said orthogonal transform processing for each of said block regions, wherein each of said filtering regions is a cluster which is included in and is smaller than said block region, and which is consisting of one or more adjacent rectangular regions, each of the rectangular regions being obtained by equally dividing each of said block regions by 2n (where n is a natural number) and each having a size of two or more pixels, and said filtering processing is performed using a low-pass filter common to said respective filtering regions.