| 摘要 |
PROBLEM TO BE SOLVED: To make a pattern, etc. corresponding to a spatial frequency not to be conspicuous when the dither processing of a bit map data is performed and an image is formed. SOLUTION: A large line-number dither processing unit 22 which performs the dither processing of the bit map data based on the dither screen of the spatial frequency lower than this; a small line-number dither processing unit 21 which performs the dither processing of the bit map data based on the dither screen of the spatial frequency lower than this; and a dither selector 16 for comparing a selected value with the tone value of the bit map data in a noted pixel in the case of forming the image by setting the tone value having predetermined density when the image is formed beforehand, selecting an output from the large line-number dither processing unit 22 when the tone value coincides with the selected value, selecting an output from the small line-number dither processing unit 21 when the tone value does not coincide with the selected value, and inputting the output to the image forming unit 7. And, the selecting value is set as the maximum tone value of maximum richness to which signs corresponding to the spatial frequency, etc. tend to be conspicuous. The image is formed with the data from the large line-number lines dither processing unit 22 of the spatial frequency to the bit map data coincident with the selected value. COPYRIGHT: (C)2006,JPO&NCIPI
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