IMAGE COMPRESSION APPARATUS, IMAGE COMPRESSION METHOD, AND IMAGE COMPRESSION PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an image compression device which improves the image quality in a short calculation time.

SOLUTION: The image compression device is provided with; a means for dividing an image into blocks; a means for selecting a direction of the maximum luminance variation in each block in a prescribed direction; a means for approximating the two-dimensional luminance change of pixels in the block to a linear luminance change only in the selected direction; a means for making approximate linear data into a vector having pixel values for deviations from the center of the block as the elements and outputting the vector number specifying the vector closest to the shape of the pixel value change out of a set of preliminarily prepared reference vectors; a means for restoring an original vector from the vector number; a means for generating restored data in a direction perpendicular to the change direction from the vector data being the linear pixel value change in the direction of the maximum change to obtain approximate surface data; a means for obtaining error between an original in the block and approximate surface data and calculating an error value of each pixel in the block; and a means for encoding error values distributed in the block.

COPYRIGHT: (C)2005,JPO&NCIPI