| 英文摘要 | As the demand grows worldwide for the public security and protection, tens of thousands of surveillance cameras are installed in the places of public activities, such as park, stadium, square, school, hospital, business street, residential block and so on. This presents formidable challenges to the browsing, retrieval and storage of the massive surveillance videos. The technology of video condensation (also called video synopsis) emerges at the proper moment. Such technology shortens the video by rearranging moving object sequences along the time axis. However, the current techniques are offline methods, and are expensive in time and space, by which they are prevented from actual use. Therefore, we propose an online content-aware video condensation solution to overcome the problems of traditional methods. Inspired by the game Tetris, our method adopts an online condensation approach. The main works and contributions of this thesis are: 1) Propose an online content-aware video condensation framework. Such framework has a natural-born ability to take 24×7 endless surveillance video and generate endless condensed video. The content-aware framework makes our method has a self-adapting condensation ratio, and this differs from traditional methods in which the condensation ratio is specified by the user. 2) Propose a novel tracking method, called sticky tracking, to eliminate the undesirable blinking effect arised from traditional tracking methods. The visual effect of condensed videos increases dramatically by the new tracking algorithm. 3) Propose an online tube filling method, including the construction of condensed space, stepwise energy optimization and reallocation strategy. 4) Propose an online principal background selection method for the purpose of generating the background sequence of condensed video. Compared to existing methods, the proposed method has advantages of high speed and low memory consumption. 5) Propose an acceleration strategy, which makes the whole algorithm achieve faster-than-real-time video condensation. 6) Implement an online content-aware video condensation prototype system. Apart from the basic function of video condensation, it has a friendly ``playback'' subsystem. In brief, the proposed online content-aware video condensation algorithm has a much higher speed, much lower memory consumption, self-adapting condensation ratio and better visual effect. The author believes that the proposed solution and algorithms... |
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