| 摘要 |
<p>PROBLEM TO BE SOLVED: To convert input picture data into pixel data with more quantization bit numbers by providing plural stages of class sorting adaptive processings. SOLUTION: Eight-bit pixel data d0 is supplied to first-stage processing parts 2 and 3. In a class sorting part 5, a class d1 is detected from the pattern of the level distribution of pixel data d0 and a prediction coefficient (w0 -w8 ) corresponding to the class d1 is read out of prediction coefficient ROM 6. A ten-bit prediction value d3 is generated from a picture element d0 and the prediction coefficient d2 by a linear first connecting expression in a prediction arithmetic part 7. In the class sorting part 8, the class d4 is generated from the prediction value d3 and pixel data d0 and the prediction coefficient (w0 -w8 ) corresponding to the class d4 is read out of prediction coefficient ROM 9. Ten-bit pixel data d6 is generated from pixel data d0 and the prediction coefficient d5 by a linear first coupling expression in the prediction arithmetic part 10.</p> |
