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dc.contributor.advisorYen-Chieh Ouyangen_US
dc.contributor.authorSheu, Jinn-Yuhen_US
dc.description.abstractA new cross search (NCS) algorithm, which can efficiently reduce the computational load, is proposed. To reduce the probability of being trapped into local minimum in motion vector search, the NCS algorithm initiates its search with multiple starting points meanwhile utilize the pixel sub-sampling method to maintain a low computational load. In order to early reject non-possible candidate motion vector, the NCS algorithm adopts a halfway-stop mechanism into the computation process of block distortion measurement. Furthermore, we introduce a threshold value to early stop if the current minimum block error is less than the threshold value. Simulation results show that by using the NCS algorithm we can reduce up to 88% computational load and 78% on average compared to the PSA meanwhile maintaining similar PSNR and MSE performance. When compares with VSA, the NCS can reduce redundant computation and improve the performance. The proposed NCS algorithm is suitable for real-time video encoding as it can speed up the encoder without sacrificing PSNR performance.en_US
dc.description.tableofcontentsChapter 1 1 Introduction1 1.1Motivation1 1.2Overview of Video Compression2 1.2.1Lossless and lossy compression3 1.2.2Transformation of Color Space4 1.2.3Motion Estimation and Compensation5 1.3Organization of Thesis6 Chapter 2 8 Architecture of Block-based Video Compression8 2.1Introduction8 2.2System Architecture of H.263 Encoder9 2.3Matching Criteria11 2.4Summary12 Chapter 3 13 Overview on Previously Proposed Motion Estimation Algorithms13 3.1Introduction13 3.2Full Search Algorithm14 3.3Logarithmic Step Search Algorithms15 3.4Predictive Search Algorithms20 3.4.1Correlation in Motion Vectors20 3.4.2Concept of Motion Vector Prediction22 3.4.3Predictive Search Algorithm (PSA)23 3.4.4Vector Search Algorithm (VSA)25 3.5Summary27 Chapter 4 28 Proposed New Cross Search Algorithm28 4.1Overview28 4.2Multiple Starting Points29 4.3The Sub-sampling Pattern Comparison for Block-matching31 4.4Half-way Stop Mechanism38 4.5The New Cross Search (NCS) Algorithm39 4.6Simulation Results43 4.6.1Computational Load Comparison44 4.6.2Performance Comparison48 Chapter 5 55 Conclusion and Future Works55 5.1Conclusion55 5.2Future Works57 Bibliography58en_US
dc.subjectNew cross search algorithmen_US
dc.subjectmotion estimationen_US
dc.subjectpredictive search algorithmen_US
dc.subjecthalfway-stop mechanismen_US
dc.subjectmultiple starting pointsen_US
dc.titleA Modified Predictive Algorithm for Block-based Motion Estimationen_US
dc.typeThesis and Dissertationzh_TW
item.openairetypeThesis and Dissertation-
item.fulltextno fulltext-
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