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방향성을 고려한 적응적 고속 움직임 추정 기법

Title
방향성을 고려한 적응적 고속 움직임 추정 기법
Other Titles
Fast Adaptive Motion Estimation Considering Directivity
Author
오창조의불
Advisor(s)
정제창
Issue Date
2007-02
Publisher
한양대학교
Degree
Master
Abstract
Recently it is very important issue that we can transmit large amount of high quality video data efficiently. The motion estimation is the most important technique for video coding which compresses vast information efficiently. In video coding, the high correlation between successive frames can be exploited to improve coding efficiency, which is usually achieved by using motion estimation(ME) and motion compensation technology. Many ME methods have been studied in an effort to reduce the computational complexity of the ME, such as block matching algorithms(BMA), parametric/motion models, optical flow, and pel-recurisve techniques, Among these methods, BMA seems to be the most popular method due to its effectiveness and simplicity. It is obvious that in using BMA, the simplest and most accurate strategy is the full search algorithm(FS), sometimes referred to as the exhaustive search of the brute-force search. The FS algorithm gives an optimum solution, in terms of prediction quality, by exhaustively searching over all possible blocks within the search window. However, the computational complexity of FS has motivated a host of suboptimal but faster search strategies. Thus, efficient algorithms such as the three-step search algorithm(TSS), the four-step search algorithm(FSS), the diamond search algorithm(DS), the Hexagon based search algorithm(HEXBS) have been developed to reduce the computational complexity. Among the proposed fast algorithms, the DS algorithm and HEXBS algorithm became the most widely used technique because of its simplicity and effectiveness. But existing fast BMA algorithms require high computational complexity. Moreover, sometimes it does not provide good reconstructed video. In this thesis, the proposed algorithm shows higher speed and better quality than existing methods such as diamond search, HEXBS. There are some main drawbacks in the DS algorithm and HEXBS algorithm such as visual quality and speed down. The proposed algorithm is modified and improved version of diamond search algorithm. And we can see that the diamond pattern is split and rotated in order to find motion vector accurately. The proposed algorithm can find motion vector adaptively depending upon image directions. Therefore the proposed algorithm performs faster block matching than existing algorithms. Finally we can obtain better results for video sequence by encoding. Also we changed PMVFAST which uses the motion vector of spatially and temporally adjacent blocks and used in MPEG-4 standard as FAST BMA algorithm. Experimental results show that, compared with the DS algorithm and HEXBS algorithm and PMVFAST algorithm proposed algorithm achieves close prediction quality as well as greatly reduces its computational complexity.
URI
https://repository.hanyang.ac.kr/handle/20.500.11754/150039http://hanyang.dcollection.net/common/orgView/200000405976
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > DEPARTMENT OF ELECTRONICS & COMPUTER ENGINEERING(전자통신컴퓨터공학과) > Theses (Master)
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