Abstract: A digital image analysis system is disclosed in which a digital input image formed by a raster scan method is so modified as to fill up a hole in a clump and a recess at the bottom of a clump viewed in the sub-scanning direction of the raster scan method, for the purpose of forming a control image, the state of a clump at two consecutive scanning lines of the control image (that is, the generation and termination of the clump at one of the scanning lines or the continuity of the clump at the scanning lines) is detected from the values of adjacent pixels on the two consecutive scanning lines, and a feature value of the clump is calculated on the basis of the detected state of the clump.