| 摘要 |
<p>PURPOSE:To improve the efficiency of coding and to improve image quality by rearranging the order of a transfer coefficient by a preliminarily prescribed sequence when the orthogonally transformed transfer coefficient is coded. CONSTITUTION:The video signal from an input terminal 11 is delayed by one frame time in a frame memory 121, and a sum frame and a difference frame are obtained from the sum and difference between two frames in an addition and subtraction circuit 122, in a time direction frequency separation circuit 12. The output is delivered to an orthogonal transformation circuit 14 via a multiplex circuit 13 and a block composed of the orthogonally transformed coefficient at every 4X4 pixel, for instance, is obtained. Next, a zigzag scan is performed for sum and difference block coefficients in a scan circuit 15. In this case, 16X2 orthogonal transformation coefficient trains are obtained. A quantization 16 is performed for these trains by a step where the front part is the finer and the rear part is the rougher and the order of the coefficient train is rearranged 17. A variable length code is allocated to the output in a coding circuit 18, and the output is coded to a prescribed coded quantity and it is outputted.</p> |
