| 摘要 |
Transform coding is used for encoding blocks of a video signal which have changed since an earlier field. Higher sequency transform coefficients are omitted. The omitted coefficients are those coefficients which, if the group were arranged, ordered as to horizontal and vertical sequency, in a rectangular matrix with the zero sequency coefficient at one corner representing the origin of x, y coordinates, x representing the position along a row and y the position along a column, would have an x coordinate less than or equal to that of the highest column, and a y coordinate less than or equal to that of the highest row, in respect of which the sum of the absolute values of the coefficients, or of an increasing substantially monotonic function of the absolute values of the coefficients, in the row or column exceeds a second threshold value which is related to the number of blocks selected in that field. Additionally a number of unchanged blocks are chosen for transform coding (replenishment). <IMAGE> |
