Motion-vector detection apparatus for a video signal

A motion-vector detection apparatus for detecting motion vectors of an input video signal, comprising:

• a frame difference accumulator for accumulating the absolute values of frame differences in each block between the present frame and the previous frame of said input video signal and outputting the accumulated value of said each block;
• a motion-vector detector for detecting a candidate motion vector of said each block and for outputting the candidate motion vector and an evaluation function value of said candidate motion vector;
• a region detector for classifying blocks of each present frame into a stationary part and motion part based on said accumulated value of each said block and outputting a threshold selection control signal;
• a first selector for selecting one of a first threshold and a second threshold in accordance with said threshold selection control signal and outputting the selected threshold;
• a comparison section for comparing a difference between said accumulated value and said evaluation function value with said selected threshold and for outputting a vector selection control signal;
• a second selector for selecting one of a zero vector and said candidate motion vector in accordance with said vector selection control signal and outputting the selected vector.