Research Of Resisting Geometric Attacks Image Watermarking Based On Cluster Template

With the rapid development of multimedia and Internet techniques, the multimedia security becomes an important and challenging research topic. Each types of digital works has to get through with lots of operation or attacks in its transmission course. These intentionally or unintentionally operation or attacks might not make the corresponding watermarking system tools detect the watermark correctly. Therefore, the robustness against each kinds of attack is always the crucial problem to watermark researchers. In the numerous types of attack, geometric attack, as a particular type in synchronous attacks, is often encoutered, and hard to resist. Thus, it always receives much concern.The thesis carries on the systematical comparatively research of the digital watermarking algorithm which based on resisting geometric attacks. Firstly, the background and the actuality of digital watermarking are introduced, and the basic concept and character, generic model, typical algorithms, attack analysis and evaluation of performance of digital watermarking techniques are dissertated. Then,focusing on watermarking of the resisting geometric attacks, some classical watermarking algorithms are presented, and their advantages and the disadvantages are analyzed.Enlightened by the existing research of watermarking algorithms, we propose a geometric-attacks-resist watermarking algorithm base on simple cluster in the image. The thesis mainly carries on three aspects work of the following:①Lead linearity fitting into the recovering to rotation attack so that the low precision problem in traditional algorithm can be improved.②Lead wavelet into the log-polar transform to improve the distortion in the traditional log-polar transform algorithm.③Lead simple cluster into the template matching to improve the disadvantage of low accuracy and ineffectiveness in the traditional template matching algorithm.Experimental results prove that the proposed algorithm has the watermark's imperceptibility and robustness of resisting geometric attacks such as translation, scale, rotation, cropping, compression etc. Finally, we review the entire work, and make the expectation of the direction for the future research of watermarking.