Research On Watermarking Technique Based On Compressed Video

The digital media has become a more fast and convenient way for information communication along with the popularization of Internet and the development of multimedia technique. But at the same time, this also leads to serious problem regarding IPR protection. So security of multimedia information becomes an important issue. Digital Watermarking technology can embed copyright information into original data without any effects on use of the data, and the watermark can't be removed, only special extracting algorithm can extract it. Digital watermarking technology can identify the digital product which has been illegally copied, and it can protect the legal copied product. So digital watermarking as an effective method of copyright protection becomes an exciting research field, especially hot the video digital watermarking.This thesis focuses on video watermarking algorithms and principles, systematically summarizes the characteristics, the classification and the research status of video watermarking algorithms and principles, and focuses the research on the key techniques of video watermarking algorithms, which include watermark generation, embedding, detection, and extraction algorithms and watermark attacks. Several traditional video watermarking algorithms are studied, and the analysis and comparison of the performances are given in detail.In this paper, a robust algorithm WET based on modulating the low-mid frequency DCT coefficients energy relationship to embed watermark is proposed. During the modulation, a theorem deduced from the texture features and energy modulation model is employed to restrict the modified magnitude of coefficients. Experimental results indicate that the presented scheme is transparent and robust to significant volumetric distortions (including additive noise, low-pass filtering and lossy compression) and a part of geometric distortions.