| 摘要 |
PROBLEM TO BE SOLVED: To provide image processing technology which acquires output images of superb image quality by performing a predetermined tone change on tone data of an input image in an image output device such as a printer. SOLUTION: Halftone processing generates a cell by successively selecting picture elements from among the tone data of the input image until a predetermined threshold is exceeded, and generates dots based on the tone value and position of the picture elements in the cell. Threshold control processing is performed to change the level of the threshold randomly for each cell. By changing the level of the threshold randomly for each cell, the size of the cell varies for each cell, and periodicity specific to the cell's position and shape is reduced. Dots are generated by a cell having a position and shape with less periodicity. COPYRIGHT: (C)2006,JPO&NCIPI
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