| 摘要 |
PURPOSE:To obtain a reproducing picture emphasizing the intermediate tone expression by setting the threshold width of a threshold value group used for multi-value processing of a chromatic reproducing picture data equal to or more than the threshold value width of threshold value group used for the multi-value processing the achromatic reproducing picture data. CONSTITUTION:A threshold value circuit 49 outputs an independent threshold value group at each color to a comparison circuit 48 in response to a color select signal from a color select circuit 47. A ROM storing the threshold value group at each color, for example, is used as a threshold value circuit 49, and in this case, the threshold value width of the threshold value group used for the chromatic reproducing picture data is made equal to or more than the threshold value width of the threshold value group used for the achromatic reproducing picture data. The comparison circuit 48 used the threshold value group at each color to apply multi-value processing to the reproducing picture data, and the multi-value processing data is used as the input data for a printer of a copying machine, from which the reproducing picture is obtained. Thus, a sharp output picture is obtained from the achromatic picture and an output picture having a sufficient intermediate tone is obtained to the chromatic picture.
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