| 摘要 |
PROBLEM TO BE SOLVED: To apply image processing for high-quality image formation in error diffusion processing using a threshold corresponding to a pixel position, or average error minimization processing using the threshold corresponding to the pixel position in the case of image processing. SOLUTION: In a halftoning unit 100 of the image processing apparatus, a correction input value calculating section 102 calculates a correction input value by adding a predetermined weight to an error value around a concerned pixel position and adding it to an input gradation value, an output gradation value determining section 103 determines an output gradation value based on the calculated correction input value of the concerned pixel position and a predetermined threshold corresponding to the concerned pixel position, an error calculating section 104 calculates, as an error value, the difference between the determined output gradation value and the correction input value, and a threshold selecting section 108 selects a threshold matrix set to settle, within a predetermined range, a rate of change of the average value of errors calculated in the error calculating section 104 for a change in the input gradation value. COPYRIGHT: (C)2006,JPO&NCIPI
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