An improved three-step search block-matching algorithm for low bit-rate video coding applications

An improved three-step search (ITSS) block-matching algorithm for motion estimation is described, specifically aiming towards low bit-rate video-coding applications. The method is based on the real-world image sequence´s characteristic of centre-biased motion vector distribution, and uses centre-biased checking point patterns and a relatively small number of search locations to perform fast block matching. The computational complexity is reduced by employing an 11×11 search window rather than the traditional 15×15 window. Simulation results are presented which show that the ITSS algorithm provides better performance at a faster speed than the well-known three-step search (TSS) algorithm and the previously developed new three-step search (NTSS) algorithm when used for low bit-rate video coding, such as in the video telephone and video conferencing