Patent ID: 6771832
Filing Date: 2004-08-03
Classification: H04N

Abstract:
An image processor that processes an image with an error diffusion method, comprising:a binary processor that transforms a target pixel into binary data; a binary error calculator that calculates an error between said target pixel and said binary data; a propagation coefficient judger that stores a plurality of set of coefficients and selects one set of coefficients; a propagation error operator that multiplies said error by said selected one set of coefficients, and outputs a result of said multiplication as a correction value; an error adder that adds said correction value to a next peripheral pixel that is input into said binary processor, wherein said propagation coefficient judger substitutes a value of 0 for said selected one set of coefficients when a change of a black point and a white point exceeds a predetermined value, said propagation coefficient judger further judging that a change of a black point and a white point exceeds a predetermined value when an absolute value of a difference between the target pixel and a peripheral pixel is greater than a reference value.