Research On Digital Watermarking Algorithms Based On Wavelet Domain

The digital media has become more and more important along with the booming development of network and data communication technology. At the same time, copyright protection of digital media is becoming a problem. As an important measure, digital watermarking technology provides a novel way to solve this problem. It accomplishes the aim of copyright protection by imbedding important information into multimedia information was protected. In this dissertation, we will study digital watermarking algorithms based on wavelet domain.We studied the still color image watermarking. And two meaningful watermarking algorithms based on wavelet domain was proposed. Meaningful watermark has many merits compares with pseudo random sequences. But it has two difficulties to solve. One is that it must has some merits of pseudo random when watermark imbedded, the other is that it has very high correctness when watermark detected. We solved these two problems in this dissertation.We applied blind detection technology, which means that original image is unnecessary when detecting watermark. Many watermarking algorithms apply non-blind detection now. Which needs original image and limits applications on copyright protection.A robust watermarking algorithm based on repeat imbedding technology was proposed. We applied scramble technology to encryption watermark and applied a new judgment technology to detect watermark. Experiment results show its robustness.A watermarking technology based on wavelet coefficient tree theory was proposed. Watermark was repeatedly imbedded into the block of wavelet coefficient tree to improve robustness of geometry attack. Experiment results are satisfactory.