Research On Reversible Visible Watermarking Technique For Color Image

With the speed development of the communication technology and widely used of computer networks,digital works extend all over our life,so people can create digital image more easily and share them on the Internet.But at the same time these works may easily suffer some illegal attacks,such as tamper,cheap copy,counterfeit and so on. As a unique product in the information age,digital watermarking technology play an important role in realizing the safe transmission of digital works and Intellectual Property Rights Protection.Digital watermarking technology is an important research direction of information hiding,it refers to hide the identification information into digital products,but it should not affect the value of the digital works.Transparency and robustness are its two characteristics.So the digital watermark technology is a powerful means to realize copyright protection and property rights certification, implied signs, to prevent the illegal use of works.Digital watermark quickly been widely promoted and applied in media,such as image,audio products,electronic commerce,etc.In this paper,the research direction is reversible visible digital watermark for color image.Though consulting related books and literature,we summarized the historical background and the status of visible digital watermarking. Depend on the in-depth understanding of current watermarking technology,we found that most of the algorithm can only embed the binary information into the gray image,and the watermark’s transparency can’t adjust smoothly,also cannot satisfy some special occasions that need non-destructive restore.In view of the above problems,we put forward a new algorithm,mainly focus on the direction and innovation points summarized as follows:(1) This paper summarizes the recent common reversible visible watermark technology.And analyzes these algorithm.(2) In this paper, each color component of24bit color watermarks is embedded into the corresponding color component of the host images with amplitude modulation. We put forward an scheme that the watermark embedding strength based on two control parameters varies with the secret key to make the watermark transparency controlled. The existence of the secret key to ensure the security of the watermark.(3) In some applications such as medical imaging, remote sensing, law enforcement, etc., tiny distortion brought by the watermark is intolerable.At such times,the watermark need to be reversible so that the source image can lossless recovery. So the quantization errors generated by integer approximation during the amplitude modulation process are collected, then embedded around the watermarking region with the difference expansion lossless invisible watermarking technology. All embedding processes are controlled by a secret key to increase the security of the watermarking approach.