IMAGE PROCESSOR, IMAGE-PROCESSING METHOD, PROGRAM FOR ALLOWING COMPUTER TO EXECUTE THE METHOD, IMAGE-FORMING APPARATUS, AND COMPUTER-READABLE RECORDING MEDIUM WITH THE PROGRAM RECORDED THEREON

摘要

PROBLEM TO BE SOLVED: To prevent granularity from being deteriorated by suppressing the occurrence of texture unique to the error diffusion method in image processing. SOLUTION: A correction input value calculation section 102 summates an error subjected to a prescribed weight by an error sum calculation section 106 to an input gradation value at a position of a target pixel entered from an image entry section 101. An output gradation value determining section 103 determines an output gradation value on the basis of magnitude relation between the corrected input value resulting from summating the weighted error to the input gradation value by the correction input value calculation section 102 and a threshold value with the periodicity corresponding to the position of the target pixel. The error sum calculation section 106 calculates a difference between the determined output gradation value and the corrected input value as an error value and transmits the error value to the error sum calculation section 106 via an error buffer 105. The output gradation value determining section 103 in an image processor 100 corrects the threshold value with the periodicity on the basis of the position of the target pixel to determine the output gradation value. COPYRIGHT: (C)2006,JPO&NCIPI