| 摘要 |
PCT No. PCT/GB86/00798 Sec. 371 Date Oct. 5, 1987 Sec. 102(e) Date Oct. 5, 1987 PCT Filed Dec. 23, 1986 PCT Pub. No. WO87/04033 PCT Pub. Date Jul. 2, 1987.A video signal is coded for transmission in a restricted bandwidth by sub-dividing a frame of picture information into a set of constituent blocks, measuring the amount of picture activity in each block, sampling the information in each block at a rate related to the amount of picture activity in that block, and adding to the coded block a supplementary signal indicating the sampling rate used for the block. Thus a decision is made on a block-by-block basis as to whether the block is transmitted with full accuracy or whether it can be adequately reconstructed from the previous frames. |
