Patent ID: 7050502

Claim:
A motion vector detection method for detecting a motion vector in a frame to be encoded which is used in motion-compensated predictive encoding of moving pictures, the method comprising: a step of dividing the frame to be encoded into a plurality of E-blocks of a predetermined pixel size; a step of predicting an amount of motion in a target E-block to be processed by using a motion vector associated with a block which is encoded before the target E-block; a step of determining a search area in a reference frame in accordance with the predicted amount of motion in the target E-block, wherein the reference frame is an already-encoded frame; a step of calculating an evaluation index for each of a plurality of S-blocks which are demarcated in the search area determined in the reference frame, the plurality of S-blocks being at a predetermined pixel interval and each having the predetermined pixel size, wherein the evaluation index represents a correlation between the S-block and the target E-block; and a step of detecting a motion vector associated with the target E-block in accordance with a temporal/spatial difference between a correlated block and the target E-block, wherein the correlated block is one of the plurality of S-blocks having a highest correlation as determined by comparing a plurality of the evaluation indices against one another, wherein the step of determining determines, from among a plurality of predefined motion estimation modes each defining a respectively different search area in the reference frame, a motion estimation mode corresponding to the predicted amount of motion in the target E-block; wherein the step of calculating extracts pixel data from within the target E-block and pixel data from within the search area in the reference frame in accordance with the determined motion estimation mode, and calculates a sum of absolute differences in pixel data between the target E-block and each of the plurality of S-blocks as the evaluation index; and wherein the step of detecting detects the temporal/spatial offset between the correlated block and the target E-block as the motion vector associated with the target E-block.