IMAGE SEGMENTING METHOD AND APPARATUS

A clear partial image of predetermined size can be segmented at high speed. The method for segmenting a partial image from a whole image comprising a plurality of pixels with gray levels comprises the steps of: inputting a number k of pixels of the partial image to be segmented; detecting a partial image maximizing: ##EQU1## where n is the number of pixels of the whole image, g(i, j) is the gray level of a pixel (i, j), .alpha. is a parameter, and .vertline.S.vertline. is the number of pixels of the partial image S; comparing the number .vertline.S.vertline. of pixels of the partial image S maximizing U.sub..alpha. (S) with the inputted number k; increasing a value of .alpha. if .vertline.S.vertline.>k and decreasing the value of .alpha. if .vertline.S.vertline.<k; again executing the steps subsequent to the specifying step using the updated .alpha.; and outputting said partial image S which maximizes U.sub..alpha. (S) if .vertline.S.vertline.=k.