IMAGE CONTOUR EMPHASIS PROCESSING UNIT AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To apply contour emphasis to a highlight part, an intermediate density area or a dark part especially in the contour emphasis processing of an image. SOLUTION: A density signal SX obtained by a logarithmic compression circuit 20 is subject to gradation correction by a 2nd gradation correction provided separately from a 1st gradation correction circuit 51 for generating a main signal SX and an intermediate signal HX is obtained and it is subject to contour emphasis by a contour emphasis circuit 40. The obtained contour emphasis signal PX is added to the main signal SZ into a contour emphasized image signal Z. A curve magnifying a desired density are adopted for a gradation correction curve for USM to be stored in the 2nd gradation correction circuit 30 to increase the emphasis of the image signal as to the density area whose contour emphasis is especially desired.