Patent ID: 7660016
Filing Date: 2010-02-09
Classification: H04N

Abstract:
1. An image-processing apparatus for quantizing multi-level (M-level) image data into N values, where M>N>1, using a multi-level error-diffusion process or a minimum-average multi-level error method, comprising: means for outputting correction data in which an error diffused from already-quantized pixels therearound is added to the multi-level image data of a pixel in question; means for setting a quantization-threshold value based on the multi-level image data of the pixel in question; means for comparing the correction data and the quantization-threshold value so as to output N-level image data; and means for calculating an error generated when generating the N-level image data; wherein, assuming quantized values are 0, 1, 2, . . . , N−1, and tones of the quantized values are V0, V1, V2, . . . , VN−1, respectively at least one threshold value Th