Study Of The Algorithms For Motion Estimation In Video Coding

With the fast develop of multimedia techniques, there are many areas need more efficient real-time compression techniques for digital image processing. In the video coding and processing system, motion estimation( ME ) and motion compensation MC ) play a very important role. They can eliminate the inter-frame redundancy and improve the performance of the video coder. On the one hand, the accuracy of motion estimation directly affects the efficiency of the video coder. It eliminates the inter-frame correlation and reduces the demand of the store memory and the bandwidth for transmitting greatly. On the other hand, the motion estimation costs most of the coding time of the encoder, there fore the complexity of the encoder lies on the complexity of the motion estimation algorithm. The research on looking for a motion estimation algorithm that can get an effective and accurate motion vector quickly becomes a hot topic to the researchers in the fieldThis article focuses on the motion estimation algorithm based on the block matching, gives summary of the main technology to improve the motion estimation algorithm .Full search is the most simple and reliable block matching method, but requires too much calculation. So many classical motion estimation algorithms have been proposed, The article makes a deep research of the previous of their method, realization, templet and performance, Based on the study of the principles of the three-step search algorithm, two modified new three step search algorithm is presented in this paper. It employed a center-biased checking point pattern in the first step, which is derived by making the search adaptive to the motion vector distribution. Experiments show that the proposed method solved the problem that the estimation results are poor under smaller motion. It improved the precision and keeps the high efficiency of the three-step search algorithm. and the result compared with the four step search algorithm shows that the new three step search algorithm is better. It is of great importance for the real time video processing.