Efficient Method for Half-Pixel Block Motion Estimation Using Block Differentials

We present an efficient method for performing half-pixel accuracy block motion estimation, as required by common video coding standards such as H.263 and MPEG-4. The estimation quality is superb, in some cases even slightly better than the conventional method, but with 44% less computation. Alternatively, computation can be decreased by 94% with only small penalty on quality. The method interpolates directly the sum of squared or absolute differences (SSD or SAD) matching criterion at integer pixel positions and subtracts a term based on horizontal, vertical, and diagonal differentials obtained from the search area.