The Research Of Spread Spectrum And Position Based Watermarking Algorithm Based On Wavelet Transform

Nowadays the multimedia technology and the Internet are developing rapidly. Information security of digital media and the protection of information property right and authentication are becoming more and more pressing and have become a very hot and important topic of discussion. Digital watermarking technology is one of the newest methods of digital production copyright protection and opened up a brand new information security way, it embedded some secret information in digital objects to prove the ownership of copyright or track the tortious behaviors, which provide an effective and potential solution copyright protection. But the ability of the digital watermark arithmetic is not enough suitable for resisting many attacks. How to improve the robust of the watermark arithmetic is becoming the key problem to be solved. Therefore, the research work in digital watermarking is of great value and practical significance.This paper considers the static digital image as the main research object, the fundamental concept, general model, classic algorithms, research situation and development direction of watermarking are introduced, and proposes two kinds of watermarking algorithms in wavelet domain, A large amount of experiments show the algorithms are available.By the researching of the Code Division Multiple Access spread spectrum in communications and the wavelet in image transacting firstly, a new watermark algorithm based on the spread spectrum and the wavelet is proposed. Watermark information is embedded redundantly in the multilevel wavelet coefficients of the cover image. By researching the structure of wavelet transform of digital image, data embedding in LH and HL bands through better spectrum spreading provides a good tradeoff between the transparency and the robustness of watermarks based on Noise Visibility Function and increases data hiding security. It is a blind detection technique of the watermark by using code division multiple access. A large amount of experiments show the proposed algorithm is effective and robust to many common image processing operations, especially to JPEG compression and filters.And then proposes an informed position based watermarking approach in wavelet domain, and compare this way to traditional watermarking approach. In contrast to traditional watermarking approaches where the information is carried by the watermark itself, in the proposed positional approach, the information is related to the position of the embedded watermarks in the image. And we propose an optimization criteria to select the best among a few available positions to embed a watermark to represent an information. In order to improve the detection performance by choosing the best available watermark which will have the least correlation to the host image to embed in a particular image. Compare this approach to traditional spread sprectrum approach and experiment in wavelet domain, results illustrate the better robustness and transparency performance when compared to spread spectrum approach, especially to collusion attacks.Lastly, compare the approaches of Position Based Watermarking and Code Division Multiple Access. Show the advantages and disadvantages and discuss how to improve them in the future.