| 摘要 |
PROBLEM TO BE SOLVED: To enhance the accuracy of coding by conducting inter-frame prediction so as to apply compression coding to information of picture elements of a moving area. SOLUTION: A coding means 11 applies inter-frame coding to image information in the unit of blocks to generate a code string and invalidates a block whose prediction error is a threshold level or below. A buffering means 12 stores the generated code string and reads it at a prescribed speed. A quantization characteristic variable means 13 controls automatically the rough/fine quantization characteristic by using stored information amount as a control variable. A threshold level storage means 14 stores a threshold level of a picture element representing a permissible maximum probability where valid block is invalidated for each quantization characteristic based on each distribution of a picture element values taking values over and less than the mean value in the process of inter-frame coding with respect to each frame and block of stadard image information. A threshold level variable means 15 gives a threshold level corresponding to the quantization characteristic subjected to automatic control among the threshold levels to a coding means 11. |
