| 摘要 |
PURPOSE:To reduce the deterioration even in the edge part of a picture with a simple constitution by changing over the quantizing characteristic when the rapid change of picture information is produced successively on a screen. CONSTITUTION:A video signal inputted from an input terminal 1, after an unnecessary part is removed by a low pass filter LOF2, is converted into digital information in an A/D converter 3, then, the difference from the output of a prediction device 9 is calculated in a subtracter 4 is calculated, supplied to a quantizer 5 as a prediction error signal and supplied to an edge detector 20. Then, when the rapid change of the picture information detected in a detecting means is successively produced on the screen, according to the detected result, the quantizing characteristic and the reverse quantizing characteristic of the quantizer 5 and a reverse quantizer 6 are changed over.
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