| 摘要 |
PURPOSE:To discriminate properly a picture and a line picture lin a color picture by deciding a picture signal to be a line picture signal when picture density levels of respective components of red, green and blue in picture signals are equal, or the level difference is below a prescribed value. CONSTITUTION:A color reading sensor 1 outputs respective chrominance signals R, G and B of a color-printed original. After these chrominance signals R, G and B are amplified to a prescribed level by amplifiers 2a-2c, the variance in characteristic is corrected by a color correction circuits 3a-3c. The corrected R, G and B signals are converted into a digital signal by A/D convertors 4a-4c, and then stored in a picture memory device 5. Information of R, G and B signals stored in the picture memory device 5 is read out by a controller 6 in a certain period, and whether or not same of R, G and B signal levels of respective picture elements are equal is judged. When they are equal, they are decided to be a line picture. When they are not equal, they are judged to be a picture or a photograph, and intermediate gradation is executed by utilizing a threshold matrix.
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