Patent ID: 7466454
Filing Date: 2008-12-16
Classification: H04N

Abstract:
1. An image processing device comprising: a pre-processing unit that calculates an average pixel value of an aggregated pixel formed of a plurality of adjacent pixels for input image data; an adding unit that calculates a correction average pixel value by adding a correction error value to an average pixel value of a target aggregated pixel to be a processing object; a quantization unit that carries out a quantization processing of the correction average pixel value at a quantization level of a prescribed number; a post-processing unit that divides the aggregated pixel into a plurality of pixels and allocates a pixel value corresponding to the quantization level to each of the divided pixels; and a surrounding error calculating unit that calculates a correction error value for processing a surrounding aggregated pixel in accordance with a quantization error generated in the quantization processing, wherein by executing a level number reduction processing, when a processing tone number per one pixel in an image output device is k, the quantization unit executes the quantization processing at a quantization level of a number smaller than [n×(k−1)+1], when the level number reduction processing divides levels from a minimum density level to a maximum density level evenly into a plurality of levels, levels from a next level of the minimum density level to a density level of a prescribed order are output as a common quantization level, and when dividing the aggregated pixel into n pixels (n≧2) by the post-processing unit, a number m of the quantization level output from the quantization unit is expressed by the following equation: m=2+(k−1)×(n−1).