Patent US 6,687,301

An encoder and method of block matching motion estimation includes accepting a current frame image and a reference image frame; dividing the frames into blocks; for each block of the current frame, searching the reference frame for a corresponding block; calculating a motion vector representing a position difference between the blocks; determining a mean motion vector for one block of the reference frame; establishing a search window; determining a mean absolute difference of the motion vector of the one block; determining a target probability of finding a minimum of the mean absolute difference searching within the search area and outside the search area; and locating the minimum of the mean absolute difference and outputting from the encoder a displacement estimation signal.