The Research And Apply On Digital Image Watermarking

With the rapid development of computer networks and multimedia technology ,the production,copy and exchange of digital multimedia are becoming extremely easier and faster .In the meanwhile,it is becoming an urgent problem to protect the copyright of digital multimedia. As a impactful measure for the problem ,the watermarking techniques has become a very active area of research.Digital watermarking is a new effective technology to resolve the problem of multimediacopyright protection and content authentication in recent years.The basic idea of digitalwatermarking is taking advantage of the redundancy in multimedia such as image ,audio andvideo,and embedding the secret information into them .The secret information is the watermarking.The background of digital watermarking is introduced firstly; the development status of digital watermarking is outlined and some typical image watermarking algorithms are studied in detail, classification and common applications of image watermarking digital watermarking are summarized; the classification of the watermarking channel is made and the current capacity theories are analyzed; the human visual system is introduced and its characteristics are analyzed in detail; Image watermarking capacity is computed and analyzed based on human visual model. The main content is as follows: Watermarking channel model is introduced and the current capacity model is analyzed in detail;The characteristics of human visual system, including the brightness, contrast sensitivity and texture hidden characteristics, are analyzed in detail, several common models of the human visual system are described. Image watermarking capacity is calculated based on the human visual model First, the spatial domain capacity is studied and the spatial domain capacity is calculated and analyzed based on Chou model, and the corresponding changes relationship between the modified coefficient and peak signal to noise ratio , watermarking capacity are given; then the DCT domain watermarking capacity is studied based on Watson model, and an modified coefficient is set up. The relationship graphs between modified coefficient and capacity, peak signal to noise ratio are obtained.