Adaptive direction search algorithms based on motion correlation for block motion estimation

The new video coding standard, H.264/AVC, has achieved significant compression gain by utilizing several advanced techniques. Block-Matching Motion Estimation is one of the most important elements to reduce the motion residual. However, it results in heavy computational burden and limits the application for real-time video service. In this paper, a fast motion estimation algorithm called Simulated Annealing Adaptive Search (SAAS) is proposed to reduce the computational load. The basic idea of the proposed scheme is based on adjusting search pattern not only for each frame, but also for each block. Initially, the adaptive search pattern is performed by statistical analysis of previous frame´s Motion Vector Correlation. Then the search pattern is adjusted for each block according to Predicted Motion Vector. According to motion vector correlation statistics information, search region is adaptively divided and Simulated Annealing (SA) mechanism is adopted to select search power for each region and to avoid trapping into local minima. Experimental results indicate that the proposed algorithm offers considerable improvement in computing time and motion search points at the same rate-distortion performance, compared to the conventional fast motion estimation algorithm.