Image processing apparatus and method and storing medium

Abstract

A system which can efficiently compress any one of a multivalue image and a binary image and can preferably keep a high picture quality is provided. To accomplish this object, the system has means for generating conversion coefficients of M values by converting input image data by a first system, means for generating conversion coefficients of N values (N>M) by converting the input image data by a second system and means for outputting first information showing a position where a significant conversion coefficient exists in a block constructed by the conversion coefficients of M values or the conversion coefficients of N values and second information showing the significant conversion coefficient. Block division information which is generated by a block dividing process as an element technique of the image encoding system is efficiently entropy encoded. To accomplish it, the system has means for outputting division information showing whether each of a plurality of blocks including an encoding subject block has further been divided into a plurality of blocks or not and means for entropy encoding the division information corresponding to the encoding subject block on the basis of a presumption probability according to a division situation of a neighboring block of the encoding subject block.