| 摘要 |
<p>PURPOSE:To make it possible to obtain the slave screen picture data of a clear picture by quantizing a picture origin signal and extracting only low frequency components. CONSTITUTION:A decoding means is provided with a quantization table for decoding 23, and master and slave screen quantization table setting means 24, 25 in addition to a Huffman decoding means 20, a reverse quantization means 21 and a reverse DCT means 22. In the quantization table for decoding 23, the table which is designated by a whole control part 26, is set by a master screen quantization table setting means 24 and is the same as the one at the time of decoding is used. A thinning means 27 extracts the only low frequency components of a fixed range in picture data decoded by the decoding means and prepares slave screen picture data. The quantization table for slave picture is set to the quantization table for decoding 23 by the whole control part 26 via the slave screen quantization table setting means 25. The table performs a reverse DCT processing for the picture data processed by the reverse quantization means 21 and extracts the only picture element of the prescribed range of the picture data whose low frequency components are decoded by the thinning means 27.</p> |
