Fast block motion estimation by edge based partial distortion search

In order to reduce the computations of motion estimation, this paper proposes a novel edge based partial distortion search (EPDS) algorithm in which the entire macroblock (MB) is divided into different sub-blocks and the calculation order of partial distortion is determined based on the edge strength of sub-blocks. In the proposed method, only selected numbers of search points are considered for candidate motion vectors. An efficient early termination method, which is based on the dynamic threshold, is also proposed to decide whether a search point has met the distortion criterion. Simulation results show that the proposed method is 108 times faster than Full Search (FS), 10 times faster than Normalized Partial Distortion search (NPDS) and 2 times faster than the dual halfway stop NPDS (DHS-NPDS) on an average. PSNR degradation of the proposed algorithm is negligible and in the region of 0.01 dB.