Patent ID: 7301673

Claim:
An error diffusion processing method of processing an input pixel of an input image to provide a binary image output on a binary output device, the method comprising: predicting a type of a dot according to a gray level of the input pixel to be processed; searching for a nearest pixel having a dot of the same type as the dot of the input pixel and is nearest to the input pixel; computing a first adjustment value of a threshold according to a difference between a measured distance between the input and nearest pixels, and an ideal distance between the input and nearest pixels, wherein the ideal distance is preset according to the gray level; computing a second adjustment value of the threshold according to a noise value of the input pixel by applying a noise array to the input image; computing a third adjustment value to avoid a diagonal pattern of pixels in response to the nearest pixel having the same dot as the input pixel existing on a diagonal line according to the gray level of the input pixel; adjusting the threshold based on the first, the second, and the third adjustment values to determine a binary value of the input pixel; determining the binary value of the input pixel by comparing the gray level of the input pixel and the threshold; changing the gray level of neighboring pixels by diffusing an error value to the neighboring pixels according to an error distribution coefficient, wherein the error value is a difference between the gray level of the input pixel and the determined binary value of the input pixel; and outputting processed pixels so that the binary image is output on the binary output device.