Patent ID: 7251060

Claim:
An image-processing device comprising: a quantization threshold produce unit producing a plurality of quantization threshold values corresponding to each of pixels of multivalued image data according to a dither threshold matrix; a random dither quantize unit quantizing said multivalued image data in multivalues by a random dither process using said quantization threshold values so as to output quantized data; a resolution convert binarize unit converting said quantized data into binary image data having a resolution higher than a resolution of said multivalued image data; and an image characteristic extract unit extracting an image characteristic of said multivalued image data, wherein said quantization threshold produce unit controls an amplitude of said quantization threshold values according to a characteristic amount output by said image characteristic extract unit, and wherein said resolution convert binarize unit determines the number of dot-on pixels to be output in a plural-pixel field of said binary image data according to a value of the quantized data of a pixel being processed of said multivalued image data, the plural-pixel field corresponding to said pixel being processed, and controls the order of arranging said dot-on pixels in said plural-pixel field according to a position on said dither threshold matrix corresponding to said pixel being processed.