| 摘要 |
<p>PURPOSE:To speedily obtain stable images at the time of transmission start or the like by controlling the quantizing characteristic of image data according to the level of correlation between correspondent blocks before and behind two continuous frames. CONSTITUTION:A data signal S24 formed by the in-frame encoding of an entire picture is transmitted to a line 1 for every prescribed frame period on the transmission side, and data signals formed by inter-frame encoding are transmitted for remaining frame period. A quantizing and encoding control circuit 29 compares differential power between two continuous frames with a prescribed value and calculates correlation with the correspondent blocks of preceding and following frames. When the correlation is high, a quantizing circuit 23 is set at the minimum quantizing characteristic or the larger quantizing characteristic and when the correlation is low, the circuit 23 is set at the maximum quantizing characteristic. Thus, when the transmission of image data is started or the like, normal regenerative pictures can be speedily obtained, and requantizing is enabled while stablizing oscillation changes.</p> |
