Research On Video Watermark Algorithm For Copyright Authentication Based On MPEG

As being a new and interdisciplinary application technology, digital watermarking technology is an important branch of information hiding. It embeds the protected and authenticated information which has been labeled the author's copyright into the kinds of digital products such as image, audio, video or software to distingiuish between unauthorized copy and transmission and protect intellectual property rights. Digital watermarking being a hot technology in present multimedia information security field has already been paid much attention by international academia and business circles.This thesis firstly pointed out the important meaning of image and video watermarking technology to the science research and industry production based on the background of problem studied, and analyzes the current status and developing trend of the digital watermarking. And then the basic principles, features and problems of watermarking and MPEG-4 were summarized. The image and video watermarking were researched thoroughly and deeply.Three algorithms were put forward in this thesis for image and MPEG-4 video: (1) Image digital watermarking algorithm was proposed based on double transformations. Put discrete wavelet transformation (DWT) into both carrier and watermark signal and embedded watermark with compromise. This algorithm has good semifrangibility. (2) An improved unblocking image watermarking algorithm based on DWT and singular values decomposition (SVD) was proposed. Utilized the properties of DWT and SVD simultaneously to embed watermark on both grey and color carriers with adaptive block decomposed quantification. This algorithm has reached high embedding quantity, well robustness and precise extraction ability. (3) Research on color watermarking algorithm based on video frames. I-frame was selected as the watermarking embedded frame. It combined discrete cosine transformation (DCT) and DWT's character with SVD's and embedded the watermarking signal into eight by eight blocks of DCT coefficients adaptively according to the texture property. This algorithm is easy to be used in MPEG-4 video. The experiment results indicate that it has well invisibility, strong robustness and extraction ability on nosing and cropping attacks.The MPEG-4 digital watermarking mentioned here is only for color watermarking technology in uncompressed video, and it has played a very impotant role on copyright authentication for video products.