IMAGE PROCESSOR, IMAGE PROCESSING METHOD, PROGRAM FOR MAKING COMPUTER EXECUTE THE METHOD, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To perform high quality image processing by suppressing noise that is apt to occur in the case of switching thresholds when applying halftone processing to image information. SOLUTION: A image processor is disclosed in which an edge detecting part 107 judges whether a pixel to be processed is located at an edge area for input image information. A threshold selecting part 108 switchingly selects a threshold set so that an average quantization error is approximately zero to a pixel judged by the edge detecting part 107 as to whether to be located at the edge area on the basis of whether to be located at the edge area. An output gradation value determining part 103 uses the threshold selected by the threshold selecting part 108 to determine an output gradation value. COPYRIGHT: (C)2006,JPO&NCIPI