Dither matrix generation method, dither matrix generation device, image processing device, and dither matrix generation program

摘要

PROBLEM TO BE SOLVED: To provide a technology to suppress deterioration in image quality due to periodical characteristics caused by use of a dither matrix.SOLUTION: A dither matrix creation method includes: a step of arranging a creation object dither matrix and a plurality of adjacent dither matrices; a step of selecting an attention threshold from a plurality of thresholds to be stored in a plurality of elements constituting the dither matrix; a matrix evaluation step of regarding that a dot is formed in a pixel corresponding to a determined element, and calculating a visual evaluation value for a case where a dot is formed in an attention element selected from residual elements is assumed; and a step of determining an element having the smallest visual evaluation value as a storage element for the attention threshold. The matrix evaluation step includes a step of executing convolution using a bandpass filter on a range including the entirety of the creation object dither matrix and at least a part of the plurality of adjacent dither matrices with the attention element as a center, so as to calculate the visual evaluation value.SELECTED DRAWING: Figure 1