| 摘要 |
PURPOSE:To prevent the titled processor from generating moires without losing gradation and color reproducibility by calculating the average density of reference picture element groups selected for respective primary colors and computing density image signals for respective primary colors. CONSTITUTION:Three circuit parts each of which consists of a dither processing part 1, a memory 2 and a picture element density conversion processing part 3 are prepared for three primary colors to execute parallel processing. The processing part 1 processes a dither pattern, a dither picture element signal is sent to the processing part through the memory 2, a sample picture element is found out, and a reference picture element is selected, the average density is found out, and then a multilevel density image signal is calculated. Said picture element density conversion processing is independently executed in each inputted color image signal, multilevel color image signals for respective primary colors are calculated, supplied to a color conversion processing part 4 and converted into multilevel output color information signals expressing respective color density signals. A series of processing is executed for all picture elements to be converted. Consequently, the picture element density conversion processing can be attained while holding the gradation characteristics and color reproducibility of the original image and the generation of moires can be prevented.
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