A Wavelet-Based Fractal Watermarking Algorithm Research Combined With Zero-tree For Digital Images

Recently, with the advancement of multimedia storage and transmission technology, especially the popularization of the internet pushes the mushroom growth of the digital media application. Many types of multimedia works such as image, video and music can be conveyed in a new way of network. These technologies bring people many conveniences, while the side effects that they cause are thoroughly obvious. For example, anybody can get the original products of others easily, especially digital products. Someone can copy and tamper the original works arbitrarily without author's agreement, which infringes gravely the author's copyright. How to protect the copyright effectively and solve the problem of information safeties on network is an urgent subject.Under this condition, as a kind of technology to solve multimedia information, security problem on network—watermarking technology comes into being. It embeds watermarks into the digital media, then carries out such functions as information hiding, store, copyright safeguarding by detecting the watermarks that can track the use of the digital media. At present watermarking technology has been a kind of effective means to multimedia copyright authentication and its integrity safeguarding.This paper takes still images as example, using for reference wavelet-based watermarking algorithm and theory basis of fractal image compression, a novel wavelet-based fractal digital watermarking algorithm that is combined with zero-tree for digital images is put forward. On the basis of layer-for-layer wavelet decomposition of image information, sieve the real nonzero tree. In the assembly of the suited wavelet-trees, looking for the most and the second fractal match tree with the image trees, which embed and detect the watermarking. It is the conception of the real zero-tree that makes the algorithm which put forward in my paper different and innovative in essence from others. Such an algorithm is simple and easy to realize, so it is expected that apply it farand wide.Finally, based on the mat-lab experimental platform, some emulated experimentsare realized by adoption of a gray-picture called "girl" that photographed by myself. From random-watermark to meaning literal-watermark, from the embedment of watermark to extraction from watermarked picture un-attacked, and from attacks on watermarked picture to extraction from watermarked picture attacked, paper proves that the algorithm is a feasible method in watermark embedment and extraction and it is reliable in robustness, imperceptivity and safety by analyzing and comparing the datum from before-mentioned experiments.