| Digital watermarking is a technique that embeds secret data called watermark into a multimedia object, such as digital images, digital audio and text. The watermarking usually is not noticeable. Digital watermarking is an effective way used in copyright protection and information security. It is playing a very important role in the applications of copyright protection and content authentication.The cover images will experience some imperceptible, irreversible or permanent distortions due to digital watermarking and the watermarked image can not be inverted back. But for some critical applications such as the fields of the law enforcement, medical and military image systems, it is crucial to restore the original image without any distortions after the watermark is extracted. Reversible watermarking is to satisfy these requirements.In this paper, reversible information hiding, and image authentication are mainly studied theoretically and experimentally, the main work of the paper is as follows:1,The basic theory of reversible watermarking hiding technology and summarizes the basic model and classification of reversible watermarking is introduced. The reversible watermarking methods of data compression, expansion and histogram modification are analyzed and the merit and demerit is also presented.2,A reversible watermarking scheme with more capability for self-recovery is presented. This scheme encodes the whole image with BCH coding method, and embeds these codes into original image with differential expansion method. For correct decoding, the location map is also encoded by BCH coding method. The experimental results prove the ability of this scheme. 3,Various watermarking algorithms for binary images, and analyzes their advantages and disadvantages is reviewed in the paper. A novel reversible binary image data hiding scheme using the correlation between the boundary pixels and its immediate neighborhood is presented. Experimental results have shown its superiority to other methods. |
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