| 摘要 |
Method for coding and decoding high definition television images subdivided into frames transmitted at a predetermined frame frequency and through a first limited passband channel implying a reduction of the quantity of information to be transmitted. The coding method comprises a stage for the local estimation of motion inside original images, a stage of treatment by a space-time subsampling of image frames effected in correspondence with the importance of a local motion found within said frames, a stage for the selection of one out of three possible transmission rates called first, second and third, on the one hand from a portion of said motion information and on the other hand from calculations of distortions between original images and processed images, and a stage of time filtering weighted according to said motion information. The decoding method comprises a processing stage by decompression of the transmitted images according to one or the other of the three transmission rates and restitution of said decompressed images to the high definition format, the restitution of transmitted images according to one of the transmission rates being carried out from motion information also transmitted by a second channel so called digital assistance channel, a stage for selecting one amongst three images thus treated according to the decision signal transmitted through the second channel, and a prior stage for a reverse time filtering weighted according to said motion information. |
