| 摘要 |
PURPOSE:To obtain sufficient forecasting effect for a picture signal having a halftone photograph and characters mixed in one block by selecting a forecast error signal, obtained by a forecasting device, by picture elements and by encoding the error signal simultaneously. CONSTITUTION:A sampled and binary-coded picture signal is applied to a terminal 1, and this sampled value X is supplied to a line memory 2 and forecasting devices 3a1 and 3a2. Those forecasting devices 3a1 and 3a2 are each composed of a shift register and a ROM, and output forecast values P1 and P2. Then, the forecast values P1 and P2 are exclusively ORed with a sample value X by exclusive OR circuits 5a1 and 5a2 to be converted into forecast error signals Y1 and Y2, which are inputted to a multiplexer 6a. Its output Y is sent to a selection signal generating circuit 4a, which sends a forecast selection signal M1 to the multiplexer 6a and an error signal E to an encoder 7. Then, the signal E is encoded and sent out from a terminal 8. |
