Research On Digital Watermarking Theory And Its Applications

Digital watermarking is a new information security technique which is growing and developing along with the rapid progress of internet and multimedia. Recently, digital watermarking is becoming the most popular research interest Digital watermarking involves with image processing, digital communication, mathematics, cryptology, information theory and other computer applied techniques. In this thesis, we will mainly research on the basic theories and applications of digital watermarking, concluded in the following five facets:1. Models of digital watermark-channel and its capacityBy introducing channel into digital watermarking,watermark-channel is formed. According to whether available side information at both encoder and decoder, a classification of watermark-channel is proposed. Impacts of embedding strength on capacity for specific watermark-channel is analysis. A computation for multiplicative watermark-channel capacity in DWT is proposed.2. Capacity of lime-varying watermark-channel with side informationA model of time-varying watermark-channel ,which include random additive and multiplicative , is proposed.. Minimal assumptions are made regarding the probability distributions of the watermark-channel. A lower and upper bounds on the watemark-channel capacity is derived. It is shown that the popular additive Gaussian channel model may not suffice in real-world scenarios.3. Optimal correlation detector in DWTFor multiplicative watermarking , A new blind image watermark detection (optimal correlative detector),which is based on generalize Gaussian distribution, is proposed.4. Robust complementary watermarking in DWTBy analysis the embedding strategy of watermarking in the DWT, A Robust complementary watermarking in DWT is proposed. A watermark is embedded in the low-frequency and mid-high-frequency.5. Applications of digital watermarking in the electronic commence...