Research Of Motion Estimation Algorithm In Video Compression

With the fast development of multimedia techniques, there are many areas need more efficient real-time compression techniques for digital image processing. Fast and efficient compression algorithm is the key for this problem. Motion estimation is rather complex in computation and occupies much time of video compression. Fast motion estimation algorithm has always been a favorite to the researchers in the related field.Firstly, this thesis expatiates the essential principle of the motion estimation based on block matching, introduces Full Search method and several typical motion estimation fast algorithms based on block matching, analyzes each characteristic, and evaluates their advantage and disadvantage through the data get from experiment, then to sum up the universal way to improve the efficiency of motion estimation. Secondly, an improved motion estimation fast algorithm based on MVFAST algorithm is proposed. The new algorithm bases on classifiable search method in MVFAST, improves the classification of motion intensity, imports relative motion intensity classification of fast moved block to adaptively choose search strategy, uses more simple search method, and finishes search adaptively. The result of experiments proved that this algorithm can improve the search speed at the even same video quality in contrast to MVFAST and PMVFAST algorithm. At last, the thesis aimed at H.263 coder, studied some optimization techniques for improving the efficiency of motion estimation algorithm in software implementation, summarized several typical optimization schemes, presented a succinct and efficient method based on bit sign to avoid repetition of search point,proposed to set the search order of points in one template based on motion vector's unequal distribution in each direction, and compared the performance of H.263 coder before and after above-mentioned optimization.