Patent ID: 8390888

Claim:
An image compressing method for compressing an image consisting of a plurality of pixels, comprising steps of: generating, on the basis of the image, a foreground mask representing individual pixels of a foreground forming a text or a line art included in the image; generating, on the basis of the generated foreground mask and the image, a foreground layer obtained by replacing color information of each of the individual pixels of the foreground with N, wherein N is a natural number, kinds of foreground identifiers; generating, on the basis of the generated foreground layer, N binary images obtained by binarizing a specific foreground identifier and a pixel value other than the specific foreground identifier in correspondence to the N kinds of foreground identifiers; setting a plurality of tiles obtained by dividing each of the generated N binary images; determining whether or not, among the set tiles, adjacent tiles are to be merged in accordance with an area of one minimum rectangular region including all of pixels corresponding to a pixel having the specific foreground identifier in the foreground layer included in the adjacent tiles; setting tiles obtained by merging the adjacent tiles determined to be merged, and leaving the adjacent tiles determined not to be merged as they are; generating a minimum rectangular region including all of the pixels included in the set tiles by utilizing the binary images; and compressing the generated rectangular region.