Research Of Digital Image Watermark Based On Bandelet Transform

Nowadays, with the rapid development of computer technology and network applications, how to solve the matter of information security, copyright protection and integrity authentication of digital media products are becoming quite important. In this background, digital water- marking is developing gradually. Digital watermarking technique is an effective protection technique, which embeds copyright information into multimedia products in order to authenticate the ownership or transmit to the available information.At present, there are two methods to realize the embedding of digital watermark: spatial domain and transformation domain. But bases on spatial domain, the quantity of watermark can not be controlled well and they are not robust methods, so people gradually embed and detect watermark base on transformation domain. Wavelet transform is a good tool to analyze image because of its'good ability, but as the limitation of its basis function, wavelet can't denote the characteristics of high-dimensional function efficiently. In this background, multiresolution geometry analysis generated. Multiresolution geometry analysis could process and express two-dimensional or high-dimensional signal sparser, as it is multi-directional and anisotropic. So this paper researches the field of digital watermarking by using the bandelets which can track the direction of the image geometry self-adaptively in multiscale geometric analysis.First of all, this paper takes the digital image as example, reviewing the basic knowledge, including development status, basic frame, feature, classification and application scope of multimedia digital watermarking technology, and then analyzes static image digital watermarking algorithm, general discusses basic mode, typical algorithm and attacks type of static image digital watermarking algorithm.Secondly, it introduces bandelet transform which is a tool of multiresolution geometry which bases on image edge, it can track image geometry regular direction self-adaptively, and with bandelets'features, it designs and implements research on algorithm of digital watermark based on bandelet domain. Through superposite the bandelets'coffiencient of original image and watermark image to embed watermark, and get much better results than DCT and wavelet.Thirdly, to avoid the inconvenient of extracting the watermarking when using the original image, this paper propose zero-watermark bases on bandelet domain. With the improved amold transform and the key processing of the watermark image, it improves the security of the watermark image and secrecy further. This algorithm can resist some common image attacks such as JPEG compression, noise and filtering. It is a robust algorithm, and it can get much better results.At last, this paper summarizes the work of this paper, and points out the direction of the further research, and prospects the direction of the development of digital watermarking.