Patent ID: 7660017

Claim:
An image processor for converting an input grayscale value of each pixel of an input image into an output grayscale value having two or more grayscales, comprising: a pixel dividing unit that divides the input image into pixel groups each including a plurality of pixels; a center of gravity position decision unit that decides a center of gravity position of said pixel group from said input grayscale value of each pixel included in said pixel group; a positioning unit that positions a center of a dither matrix on the center of gravity position of said pixel group; and an output unit that acquires said output grayscale value by corresponding said positioned dither matrix and said input grayscale value of each pixel included in said pixel group, wherein said dither matrix has a plurality of elements such that as the element is closer to the center of the dither matrix, the output grayscale value with dot being more likely generated even if the input grayscale value of the input image is small is acquired.