| 摘要 |
PURPOSE:To obtain an ideal level characteristic by converting the analog color separation signals of three colors into the digital color separation signals to decide the levels of these three signals, performing a prescribed operation for those three digital color separation signals based on the result of said level decision and comparing these levels with a prescribed slice level to produce color signals. CONSTITUTION:Color signals R, G and B are supplied to a 3-channel A/D converter 26 and converted into 4-bit digital signals RD, GD and BD. These digital signals are supplied to comparators 33-35 of a level deciding circuit 27 as well as to selectors 28-30 respectively. The outputs MAX and MED of selectors 28 and 29 are added to an adder 54, and the sum MAX+MED is applied to a comparator 56 and an adder 55. Slice levels SL1-SL3 are set to comparators 56-58 as the standards of comparison respectively. An output COL1 which is set at a high level is obtained with the comparator 56 when MAX+MED<SL1 is satisfied. While outputs COL2 and COL3 which are set at high levels are obtained with the comparator 57 or 58 in the case of MAX+MED+MIN>SL2 or SL3 respectively.
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