Based Zero-watermark Dynamic Multiple Watermarking Algorithm

The digital media offers the great facility for the access of the multimedia information and it improves the efficiency and accuracy that the information expresses at the same time .With the development of computer networks and multimedia technology, copyright protection and authentication becomes more and more urgent. Therefore, as a main method for copyright protection, watermarking has been widely applied .People often think that the realization of the communication security can be finished through encryption. That is, at first we can encrypt the multimedia data works, we can publish so that illegal assailants who appear in the packet transmission course can not win secret information from the cipher-text, and it achieves copyright protection and information safe purpose .But this can not solve the problem, on one hand, since we cannot understand the meaning of the works after encrypting ,it hinders the spreads of multimedia information; On the other hand assailants are attracted by multimedia information after encrypting , and its content is totally transparent once the cipher-text is decrypted. The cryptography has been considered to be the main information safe means in communication, people paid attention to this subject greatly, and this kind of situation has changed until recent years. People try to hide the secret information into the ordinary works and distribute them, so that we can follow tort and offer legal protection, this can be called information hiding and maybe Steganography is more exact. The 'Steganography' stems from ancient Greece; it means that the useful or important information will be hidden in other information so that we can not find the useful information. The different exists between Cryptography and Steganography, because Cryptography protects the content of the information, but the Steganography makes people think that the information does not exist.As a potential and effective way to protect the copyright of digital products, digital watermarking becomes a very active research area of signal and information processing. Watermarking is a technique for labeling digital pictures by hiding secret information into the images. Sophisticated watermark embedding is a potential method to discourage unauthorized copying or attest the origin of the images. The watermarks embedded may be some words, symbols, ID sequence etc. watermarks usually are imperceptible for the vision and hearing, they are embedded into the cover work (such as images, audio frequency and video frequency) and can not be separated from the source data, they remain efficient by some operations which do not destroy the use value and the business value of the source data.In this paper, I study digital watermarking of images. I have read a large amount of documents and materials about digital watermarking technology. And the fundamental principles of watermarking techniques including the last achievement in this field are introduced. The procession models and the typical methods are analyzed.At present the research about digital watermarking concentrates on space domain and transform domain, we embed the "watermarks" by selectively modifying some coefficients of the image or some pixels of the space domain. In space domain, The digital watermark of space domain superposes the watermark information on the signal space directly, Change vision alike plain values, generally in adding the watermark signal modulated in being vision the luminance or typewriter ribbons of element. In general, this algorithm does not use much compute, and it contains a lot of information, and we can not percept the watermarks easily. But for some reasons, the watermark may be lost during the signal processing. So in space domain, other kinds of attacks, such as image resembling and image rotation, are still challenging to our current work, in transform domain, the general algorithm uses transform technology, in order to splice the information and it gains efficient coding of watermarks through spread-spectrum communications, so our algorithm has very excellent effect.ChapterⅣpresents a paper on adaptive DCT embedding operator. A block DCT-based 2-dimension image watermarking algorithm for images is proposed in this paper. Most digital watermarking use pseudo random sequences as watermarks and so they only answer 'yes' or 'no' for detecting the watermark. In some circumstances, we need embed meaningful watermark. Therefore, the algorithm of choice meaningful chaotic sequence spread spectrum watermark image. We put the DCT algorithm in the field and on the relative importance of the choice of the frequency domain, frequency coefficient watermark embedded in the signal location .Embedding determined by the intensity and location of embedded adaptive embedded operator to determine. Finally we realize this algorithm to be robust and a lot of tests and experiments. The experiments show that this method gives a good robustness.Based on the wavelet transform, robust watermark is watermark-depth understanding of the fragile watermark. In Chapter 5 presents a multi-watermarking algorithm. And the fragile watermarking algorithm robust watermark embedding. The algorithm has made copyright protection function and has anti-tampering function; Zero more robust watermark feature watermark is added to the algorithm to improve the robustness of the algorithm. Then, we realized algorithm and a lot of robust testing laboratories. The experiments show that the algorithm is robust. Finally, the weakness of the corresponding algorithm theory solutions; Meanwhile, A watermark is a geometric algorithm and the anti - watermark is meaningless watermark is a solution to the shortcomings of the program.Finally, we get a review of this paper. The paper was also the inadequacies of digital watermarking for possible future research directions in the future.