Watermarking Techniques Of Digital Images

With the rapid development of computer networks and multimedia technology, the production,copy and exchange of digital multimedia are becoming extremely easier and faster. In the meanwhile, it is becoming an urgent problem to protect the copyright of digital multimedia. As a impactful measure for the problem, the watermarking techniques has become a very active area of research. Recently, there are many watermarking algorithms,softwares and applications. However, allof them are in infancy and remain many challenging problems. So this thesis focused on the research of the watermarking for the copyright protection and communication security of digital images.This paper generally overviewed the framework of watermarking, its characteristics and application. Research prospect in watermarking techniques was pointed out. On the basis of analyzing design flow of watermarking system, the crucial sequences of digital watermarking techniques were generalized. In order to improve the performance of watermarking technique, the watermarking was done chaotic sequences. Generally, the effect of chaotic sequences was made better, the invisibility was better and anti-detection ability was higher when the watermarking was hidden after the carrier information as secret information. In this paper, digital chaotic signals were combined with Hamming code. A method to improve the robustness of watermarking was proposed. Experimental results proved its effectiveness.The embedded algorithm for the watermarking was studied. The watermarking algorithm in different area was systematically summarized. The robustness of watermarking algorithm was designed by a new transform domain, namely, multi-band wavelet domain. Multi-band wavelet solved some certain limitation of binary wavelet. It was possessed of frequency-band characteristics such as short support orthogonality symmetry. It was realized by multi-embedded of watermarking and Hamming code. The experiment result proved that it can meet the requirements of watermarking robustness and invisibility, being superior to the traditional wavelet domain.