IMAGE PROCESSING SYSTEM

According to the image self-alignment system of the present invention, desired partial image areas are extracted by a partial image area designator from a pair of to-be-aligned picture images used for, for example, medical purposes. Each partial image area is divided by an area divider into a plurality of image segments arranged in a matrix form. Each corresponding image segment pair is subjected to a first misalignment detection by using a first evaluation parameter called correlation coefficient data. Each image segment pair is then subjected to a second misalignment detection by using a second evaluation parameter including pixel density difference data for finer detection. The first and second picture images are automatically aligned based on highly reliable final misalignment data obtained by carrying out the first and second misalignment detections.