1. A method for comparing an image signal between adjacent frames and estimating a motion of the image, the method comprising the steps of: constructing a first image segment representing a portion of present image frame and a second image segment having a plurality of image segments of an adjacent frame; comparing said plurality of image segments of said second image segment with the image signal within the first image segment, and generating a number of error values; detecting a first motion vector at one scale of resolution using the generated error values; outputting the error value associated with a reference segment pointed by the first motion vector, and the error values corresponding to the reference segment shifted by one unit of selected resolution respectively in selected direction(s); generating a second motion vector in finer scale of resolution using the output error values; and summing the first and second motion vectors.