THRESHOLD MATRIX, AND GREY LEVEL REPRODUCING METHOD AND DEVICE UTILIZING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a threshold matrix where the regularity of a dot pattern in a local area is enhanced so as to improve problems of the uniformity and a virtual image thereby obtaining a visually excellent dot pattern and to provide a grey level reproducing method and device utilizing the matrix. SOLUTION: When a gray scale in each pixel of an output image is expressed in binary or a multi-value by making each pixel of an original image corresponding one to one to each element of the threshold matrix, a dot pattern with a size corresponding to the threshold matrix is divided into small area divisions so that number of dots is equal in all the area divisions for all grey levels and the dot patterns in a plurality of the area divisions are equal to each other, and the threshold matrix is created based on the dot pattern formed by providing a repulsive force whose shape is adjusted to each dot in a way that a dot can easily be set to a pixel at a particular position in a local area around an existing dot for a plurality of grey levels.