| 摘要 |
PROBLEM TO BE SOLVED: To display a picture with good void on a PDP(Plasma Display Panel) with well-working APC(Automatic Picture Control) even when APL(Average Pitcher Level) is large. SOLUTION: After input video signals S1r, . are digitalized by an A/D converter 6, the APL is determined by adders 1, 2 and a substracter 3 to be stored into the APL register. Using the output of the register, the gain for each color signal is read out from the gain table, ROM 5, and multiplied by the input video signal using the multiplier 7r, . to obtain a color component conversion signal. The differences between each color of input video signals are detected by the difference circuit 9rg, . and compared with the output of the void region register 10rg, . by the comparator 11rg, to obtain signals representing the void regions at each color difference. From this signal, the void region signal of input video signal is obtained. By switching the switcher 8r, . using the void region signal, color component conversion signals in the void region and output video signal S2r, . giving the input video signal in the regions other than the void region are made to be displayed on the PDP. |
