| Summary: | 博士 === 國立交通大學 === 資訊科學與工程研究所 === 96 === In this dissertation, we propose a progressive image watermarking scheme and a video fingerprinting scheme for copyright protection of multimedia applications on the Internet. The ease of transmission and copying of images creates the need to use digital watermarking to embed the copyright information seamlessly into the media. On the other hand, progressive transmission of images is very useful in many applications, especially in image transmission over the Internet. Since the progressive image transmission has been widely used, in this dissertation, we first propose a progressive image watermarking scheme. In this scheme, the watermark is embedded in such a way that we can retrieve part of it even when the watermarked image is still being transmitted. As transmission progresses, the retrieved watermark has a decreasing bit error rate. Our proposed method can not only detect the watermarked image progressively, but also intelligently select watermark embedding locations and is robust to various attacks.
We also propose a new video scrambling and fingerprinting approach for digital media right protection. The proposed method contains two parts: (1) video scrambling at server side, and (2) fingerprint embedding at client side. First, a content server scrambles and multicasts video contents to end users. Then, by applying a (v, k, 1)-BIBD scheme, the server partitions a descrambling key into v=O(sqrt(n)) descrambling subkeys, and multicasts to n users. On receiving descrambling subkeys from the content server, each user combines descrambling subkeys into a descrambling key embedded with a fingerprint. By using he's descrambling key, a scrambled video becomes a fingerprinted video designated to the user.According to the experiment results, when the fingerprint consisting of less than 15 watermarks or watermark strength a s less than 0.5 the PSNR of video frames can be 35 or higher. Thus, this approach is suitable for multimedia applications over The Internet.
Finally, an integrated information mining techniques for multimedia TV-news archive is addressed. The utilized techniques from the fields of acoustic, image, and video analysis, for information on news story title, newsman and scene identification. The goal is to construct a compact yet meaningful abstraction of broadcast news video, allowing users to browse through large amounts of data in a non-linear fashion with flexibility and efficiency. By using acoustic analysis, a news program can be partitioned into news and commercial clips, with 90% accuracy on a data set of 400 hours TV-news recorded off the air from July 2003 to August of 2004. By applying speaker identification and/or image detection techniques, each news stories can be segmented with an accuracy of 96%. On screen captions or subtitles are recognized by OCR techniques to produce the text title of each news stories. The extracted title words can be used to link or to navigate more related news contents on the WWW. In cooperation with facial and scene analysis and recognition techniques, OCR results can provide users with multimodality query on specific news stories. Some experimental results are presented and discussed for the system reliability and performance evaluation and comparison.
The proposed web based TV news archive was also used as a test bed of the proposed image watermarking and video fingerprinting methods. Watermarks can be embedded automatically when key frames of a news story are extracted, and information obtained from video analysis process can be used to increase the robustness of video fingerprinting. In multimedia applications, computational efficiency is one of the important issues. Our testing shows that the proposed watermarking and fingerprinting methods are efficient to real world applications.
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