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標題: 一種適用於低位元速率視訊壓縮之預估性區塊匹配移動估算快速演算法
A Fast Predictive Block-Matching Motion Estimation Algorithm for Low Bit-Rate Coding
作者: 沈志賢
關鍵字: motion vector;移動向量;predictive motion estimation;block-matching algorithm;H.263 three-block median predictor;預估性移動估算;區塊匹配演算法;H.263 三區塊中位數預估器
出版社: 電機工程學系

For low bit-rate video coding, predictive block-matching motion estimation algorithms have been used to replace the logarithmic step search algorithms because the motion vector searching time can be greatly reduced by utilizing the correlation existing in motion vectors. However, these algorithms still suffer from their large computations if the initial prediction is not accurate enough. As a result, the motion vector searching time can vary acutely from frame to frame. In this article, we investigate the correlation among motion vectors (MV). Our study shows that the x component of MV is more related to its vertical neighbor MVs while the y component of MV is more depedent on its horizontal neighbor MVs. Based on the observation, we design a modified three-block median predictor to improve the motion vector predicting accuracy. By employing the predictor, a fast predictive block-matching motion estimation algorithm, the vector search algorithm (VSA), is proposed. Instead of checking all locations in the search area, the VSA only searches locations in the most probable direction. Simulation results indicate that our algorithm is much faster than other fast search algorithms as well as maintaining similar or better performance in terms of mean-square error measurement.
Appears in Collections:電機工程學系所

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