| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an extended picture with high quality even in operating the picture compression of an input picture in which a CG picture area and a reading picture area coexist by using a multi-mode compression system by adaptively setting a block central value based on a featured value related with the frequency distribution of inputted picture data and the distribution state of a detected distribution range edge part neighborhood area. SOLUTION: A raster block converting circuit 3 outputs inputted picture data DG as a block picture BG with 8×8 picture elements as one unit. A picture characteristic judging circuit 4 judges whether a picture in the block picture BG is only a reading image area, or CG picture area, or both areas by calculating characteristic values such as the maximum number of gradation, dynamic range, and complexity of the block picture BG, and considering the correlation of those characteristic values, and controls selectors 5 and 8 to allow the picture data to pass through an ADCT encoding circuit 6 or a BTC encoding circuit 7. Thus, efficient encoding can be attained, and an extended picture with high quality can be obtained.</p> |
