Research And Application Of Digital Watermarking Based On Chaos

With the rapid development of Multimedia Information Technology and Internet, the problem ofprotecting the copyright has become more and more serious. Digital Watermarking, which is one importantsubsidiary field of Information Hiding and an effective means to protect the copyright, is receiving anincreasing attention.This article focuses on the excellent properties of Chaotic Sequence and its application in DigitalWatermarking, the following are the main points:Firstly, the author summarizes the basic concepts, theories and main knowledge for the DigitalWatermarking Technology and the relative theories, such as Discrete Cosine Transform, Wavelet analysisand Chaos Theory. At the same time, by introducing the development, present status and future of DigitalWatermarking Technology the author proposes the aim of this dissertation.Secondly, the author puts forward a Blind Watermarking Algorithm basing on DCT Domain and Chaos.That algorithm, in which a binary image with practical meaning is selected as the watermark, is encrypted bythe Chaos Sequence generated from Composite Nonlinare Discrete Chaotic Dynamical systems. Such, whenexamining the algorithm, no original imagine is needed. Lastly, make an analysis of the results of the imitatedexperiment to prove that the plan is practical. And the experimental result shows the robustness of thisalgorithm.Thirdly, the author points out two Watermarking Algorithms basing on wavelet and chaos. These twoalgorithms, in which the gray-level image with practical meaning is selected as the watermark, are encryptedby the method basing on Chaos Sequence. In watermark embedding domain, the Discrete Wavelet Transformwhich has a similar human visual system characteristic is employed (The first method of algorithm is toembed the watermark in DWT low frequency field, while the second one is to embed the watermark in DWTmiddle-high frequency field).Watermark is embedded into certain one or several sets of Wavelet Coefficientsto improve the watermark embedding agility. It is not only simple but also secure to use the initial value of theChaotic Sequence as a key to embed and detect signals. Performances, after evaluating the possibilities of twoalgorithms under all kinds of attacks, are proved effective and robust both in theory and experience.