MOVING PICTURE CODER

摘要

PURPOSE:To suppress a transmission information quantity of a background block, to keep the quality of a picture of a communication party and to improve the movement of the communication party by applying discrimination of valid/ invalid block to a background block not including a picture of the communication party with a threshold level higher than that of the block including the picture of the communication party. CONSTITUTION:The coder is provided with a means discriminating whether or not a color component of an input picture signal is within a range of a threshold level for each small block. When number of picture elements discriminated to be within the threshold range is a threshold level or over, and with a means discriminating the block to be a block (communication object block) including a communication party and discriminating the block to be a background block. Then a valid/invalid block is discriminated to the communication object block with a usual threshold level and the background block is discriminated with a higher threshold level. Thus, the picture quality is kept for the communication object block as usual and the transmission information quantity is less in the background block and the communication object blocks are much sent.