| 摘要 |
PURPOSE:To decrease code words to be assigned to picture data by assigning a short bit column to input data whose occurence frequency is high, and assigning the long bit column to the input data whose occurence frequency is low. CONSTITUTION:A frame memory 1 reads block picture data from a picture to be encoded based on a block designation signal. On the other hand, the frame memory 1 reads area picture data based on an area designation signal, and a converter 6 converts the data according to a prescribed converting method. A comparator 4 calculates the approximation of the block picture data and the converted area picture data. A code assigning equipment 8 assigns the intermediate code word of the pertinent block to the area designation signal and a converting method designation signal corresponding to the stored maximum approximation. A subtracter 10 calculates a difference between the pertinent intermediate code word and that corresponding to the block picture data at the same position before one frame held by a memory 9. Then, a variable length encoder 11 assigns the short bit column to a difference value whose occurence frequency is high in the neighborhood of zero and assigns the long bit column to the other difference value. |
