| 摘要 |
<p>PURPOSE:To suppress effectively a DC component by assigning a code word and a digital sum CDS code to data corresponding to a level having a small absolute value and allowing the polarity of the CDS to correspond to the polarity of a level represented by the data thereby improving the possitibility of alternate generation of the data. CONSTITUTION:A forecast signal P is subtracted from an input image data signal Di by a subtractor 11 of the coding system, the result is quantized by a quantizing device 12 to output an output data signal DO. The signal DO is fed to a representative value setting device 13 of a local composite device 16 sending forecast signal P and supplies a representative signal R to an adder 14. The adder 14 adds the signal R to a feedback value form a forecast device 15, the sum is fed to the forecast device 15 and the forecast signal P is fed to the subtracter 11. Then a code having a small CDS value is assigned to the data corresponding to the level having a small absolute value, the polarity of the CDS corresponds to the polarity of the level of the data to suppress effectively the DC component.</p> |
