A new three-step search algorithm for block motion estimation

The three-step search (TSS) algorithm has been widely used as the motion estimation technique in some low bit-rate video compression applications, owing to its simplicity and effectiveness. However, TSS uses a uniformly allocated checking point pattern in its first step, which becomes inefficient for the estimation of small motions. A new three-step search (NTSS) algorithm is proposed in the paper. The features of NTSS are that it employs a center-biased checking point pattern in the first step, which is derived by making the search adaptive to the motion vector distribution, and a halfway-stop technique to reduce the computation cost. Simulation results show that, as compared to TSS, NTSS is much more robust, produces smaller motion compensation errors, and has a very compatible computational complexity. >