METHOD FOR CORRECTING PIXEL ARRANGEMENT OF IMAGE AND METHOD FOR DECIDING THRESHOLD VALUE ARRAY FOR GENERATING IMAGE

摘要

PROBLEM TO BE SOLVED: To reduce an undesired low frequency component such as moire by correcting a black level pixel position of image data. SOLUTION: In the case of correcting the arrangement of a black level pixel in dot image data H with a gradation formed by an aggregate pattern of dot cells having dots comprising one black level pixel or more, this method adopts novel procedures such that a low frequency component extract section 45 and a pixel decision processing section 46 extract a low frequency component of a screen frequency component or below from the dot image data H, apply frequency analysis to the data H, compare the intensity of each pixel as a result of frequency analysis with the intensity of each corresponding pixel configuring the dot image data H and correct the black level pixel position so that the frequency component as a result of the analysis is not emphasized. Thus, a moire component being a low frequency component in dot image data H is reduced.