CIRCUIT AND METHOD FOR DETECTING MOTION VECTOR

PURPOSE: To optimize operation quantity and accuracy in the detection of a motion vector, the degree of compression of a moving image and the picture quality of a compressed moving image. CONSTITUTION: This system is provided with a circuit 36 for deleting the lower bits of each digital data indicating each picture element value in a current macro block, a circuit 38 for deleting the lower bits of each digital data indicating each picture element value in a reference picture, a detection circuit 40 for mutually comparing outputs from the circuits 36, 38, searching an area most similar to the current macro block from the reference picture and setting up the searched area as a reference macro block, and circuits 46, 48 for selecting an output from an intra-encoding circuit 52 and an output from an inter-encoding circuit 50 in accordance with the compression efficiency of respective circuits 52, 50.