CODER, DECODER, CODING METHOD, DECODING METHOD AND PROGRAM THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an image coder capable of generating code data of an image including a plurality of image elements overlapped with each other at a high compression rate with high image quality. SOLUTION: An image dictionary generating section 420 generates a density dictionary and a shape dictionary on the basis of an input image received from a raster generation section 400, shape information, positional information, and overlap information of the image elements. A shape extract section 422 extracts the shapes of the image elements as a shape pattern, and allows a shape inversion section 428 to invert the shapes of the image elements to extract an inverted shape pattern when the image elements are overlapped. A dot image extract section 42 extracts a dot pattern on the basis of the input image. An index provision section 426 provides indices for identifying the shape pattern and the dot pattern to the respective patterns. A code generating section 440 codes the image elements included in the input image on the basis of the density dictionary and the shape dictionary. COPYRIGHT: (C)2006,JPO&NCIPI