DITHER MATRIX, IMAGE PROCESSING METHOD, STORAGE MEDIUM, IMAGE PROCESSING APPARATUS, IMAGE FORMING APPARATUS, AND IMAGE FORMING SYSTEM

摘要

A disclosed dither matrix is used in halftone processing for converting input image data having M input halftone levels into output image data having N (M > N > 2) output halftone levels. In the halftone processing, a concentration type dither matrix is used as the dither matrix when an input halftone level is within a range of input halftone levels corresponding to an output halftone level that is lower than a predetermined threshold level T (N > T > 1), and a dispersion type dither matrix is used as the dither matrix when the input halftone level is within a range of input halftone levels corresponding to an output halftone level that is equal to or higher than the predetermined threshold level T.