| 摘要 |
The invention relates to a method for compressing a digitally coded video image in connection with transmission. In the method, image information is transmitted as successive image blocks (PM) each comprising n x m pixels, and the image block (P1) to be transmitted is compared with at least one previously transmitted image area of equal size to determine the correspondence therebetween. In order to be able to utilize the fine structure recurring within the image or areas having a substantially constant intensity value in the compression, the image block (P1) is compared with an image area contained in the same field, and (i) if at least one image area meeting a predetermined correspondence condition is found, one of said image areas is selected as a prediction block for the image block to be transmitted, and (ii) if the predetermined correspondence condition is met by none of the image areas under comparison, an image block in which the intensity value of each pixel is zero is taken as a prediction block, and a difference image is calculated from the image block to be transmitted and the prediction block, and the difference image and position data concerning the prediction block are transmitted to a receiver, the position data comprising a predetermined code word in case (ii). <IMAGE> |
