The Research And Implementation Of Geometric Attacks Invariant Wavelet Field Digital Watermarking Algorithm

With the booming development of multimedia technology and the popularity of Internet, distributing of digital products through Internet becomes an important spreading way of new civilization. But how can we protect the author's copyright and economic profits? Digital watermarking technology is an effective way of copyright protection in recent years. At present, the ability of counteracting geometric attacks hasn't completely achieved the request of application. The geometry transform attack is considered as a pivotal problem to improve the robustness of watermarking algorithm. With the development of Digit and Internet, the application value of watermarking will more outstanding. So it is urgent to improve the ability of counteracting geometric attacks of watermarking algorithm.In the article, the research situation, character and shortage of geometric attacks invariant watermarking algorithm and wavelet field watermarking algorithm are analyzed firstly. And the fundamental concept, general model, classic algorithm are introduced. Then the image moment based geometry transform parameter estimate algorithm is researched and implemented, which make it more effective with less image moment information. Based which, a Geometric Attacks Invariant Wavelet Field Digital Watermarking Algorithm is designed. In this algorithm, the estimate of geometry transform parameter is a pretreatment process. Before detecting the watermark, the geometry transform parameter is estimated, and then the image is renewed. At the same time, the watermark is embedded both in intermediate frequency and in low frequency of wavelet. In the process of embedding, the HVS is combined and the watermark is embedded adaptively according to the character of the image.Experimental result shows that this algorithm can estimate the geometry transform parameter of translation, rotation and scaling well and truly. The clarity of image embeddedwatermark is good. At the same time, it is immune to translation, rotation, scaling, cutting, JPEG loss compression, median filter, and sharping.