| Content-based multimedia retrieval has been a hot research field recent years. As a part, news video retrieval has been studied widely. News video is one of the most important media for users to get the information. It is an urgent problem to retrieve the interested news from a huge amount of news video efficiently and correctly. This paper takes news video as a research object, and discusses several problems in the process of content-based video retrieval, including shot segmentation based on cut detection, key frame selection, topic caption retrieval, news story segmentation, news video retrieval based on keywords.(1) Video segmentation is the first step, this paper offers a video shot detection method which is based on self-adapting dual-threshold compare, to complete the detection of the cut and the wipe, which achieves good experiment results. Because topic caption contains important semantic information, this paper offers a key frame selection method based on the frame of topic caption, which basically can show the content of the shot.(2) The retrieval of topic caption contains three parts. First based on analyzing of recent researches, as to the caption detection, the caption detection method is designed, which is based on texture features of 3/10 spatio-temporal slice. Secondly, the caption location method is adopted, which is based on wavelet transformation and SVM and achieves good experiment results. Thirdly, it employs the interpolation method to enhance the caption, then binary and partition the caption, and it uses the given Han Wang OCR software to recognize the characters.(3) Based on the research of news story segmentation, the method based on caption is discussed to the segmentation of news. Based on the retrieval of the caption, and the detection of slice and anchorperson shot, news video is segmented into a series of news story, and the experimental result indicate that this method is efficient. Based on the result of news story segmentation and the label of topic caption, the news retrieval based on key word is realized. |
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