The Research Of Color Image Digital Watermarking Based On Ridgelet Transform

With pictures,video and other multimedia applications expanding rapidly in internet business,digital products are confronted with sterner challenges in copyright protection and query-verifying.Digital watermark is one of the most critical technical means of digital copyright protection,and a research focus in network security field.Therefore,this paper is to research on principles and methods of digital watermark.In this paper,a new algorithm of digital watermark based on color picture of ridgelet transform is presented.Firstly,this paper introduces the principles,the basic features,the development course and the present domestic and overseas conditions of digital watermark.Then,it puts forward a basic frame of digital watermark,with detailed description of all the parts of the frame.Digital watermark can be classified according to their different characteristics,which provide a theory basis for digital watermark algorithm of design and implementation.In this paper,a new algorithm of digital watermark based on color picture of ridgelet transform is presented.With the important visual information in the picture with Sparse linear singularity characterization of ridgelet transform,the robust watermark is embedded into the low frequency coefficients of image.Then,the fragile watermark is embedded into the high frequency coefficients of image.The strength of the embedded watermark will be determined by the overall energy situation,which can achieve the realization of adaptive watermark embedding and can improve the robustness of watermarking.This method is to select the embedding strength according to the image local ridgelet coefficients,ensuring the invisibility of watermark.The paper also puts forward a multi channel color image digital watermarking algorithm based on ridgelet transform.The algorithm makes the best of the characteristics of different color components in the watermark.Using relative quantitative way to embed the watermark into the blue and green access of after ridgelet transform,it can improve stability of algorithm when watermark image has been attacked by the brightness and contrast adjustment.Experimental results have demonstrated that two algorithms of digital watermark in this paper can make obvious progress both on the invisibility and on the anti-attack,which is robust to resist normal and geometrical attack.