| 摘要 |
<p>PURPOSE:To reproduce a character part with high quality, to prevent production of ringing and to save a high frequency component by applying BTC coding to the character part including much high frequency component and taking a difference between the BTC decoding picture and an input picture. CONSTITUTION:An input picture data inputted from a picture input section 1 is discriminated as to whether it is a character part or not for each block by a classification section 2 and the block discriminated to be a character is given to a BTC(Block Truncation coding) section 3, where the pattern is expressed as one bit and a difference P1-P2 being a difference between mean values P1 and P2 is coded. A BTC decoding section 4 uses signals 101, 102 to reconstitute the picture and only the character block is reproduced. A differential device 5 takes a difference between the reproduced picture and the input picture and its output is coded at a DCT(discrete cosine transformation) coding section 6. Thus, a character part including much high frequency component is coded by the BTC to eliminate the high frequency component thereby preventing production of ringing.</p> |
