Patent ID: 6718064
Filing Date: 2004-04-06
Classification: G06T

Abstract:
An image compression apparatus comprising:a reduced image generating processor that generates, based on original image data arranged in a first matrix comprised of a plurality of pixels, reduced image data arranged in a second matrix comprised of a smaller number of pixels than said first matrix; a reduced image area setting processor that sets a reduced image area, which is defined by a sub-matrix, obtained by displacing said second matrix in a predetermined displacement direction by a predetermined amount, and contains an objective pixel also contained in said reduced image data; a first orthogonal transforming processor that applies orthogonal transformation to said reduced image data of said reduced image area to obtain reduced orthogonal transformation coefficient data; a first expanded image generating processor that applies inverse orthogonal transformation to said reduced orthogonal transformation coefficient data to obtain expanded image data arranged in a third matrix comprised of a greater number of pixels than said second matrix; an evaluation function calculating processor that calculates a value of an evaluation function, which corresponds to a difference between said original image data and said expanded image data; and a displacement-amount selecting processor that selects said displacement direction and amount of said reduced image area, for every said objective pixel, in such a manner that said value of said evaluation function becomes a minimum.