Research On Digital Image Watermarking In Wavelet

The fast development of Internet makes it convenient to access the multimedia data, but at the same time the Internet has brought a new challenge to the copyright protection. As an effective means for the protection of digital property rights, the technique of digital watermarking is an important part of the region of information hiding and attracts wide attention. Digital watermarking is a technique that embeds copyright information, such as figures, sequence numbers, words, and image logos and so on, imperceptibly into multimedia data. It can be used for tracing the distribution and usage of multimedia data. The special application of digital watermarking technique requires that the embedded watermark should be not only transparent to human observers, but also robust enough so that it cannot be easily destroyed or removed after some digital image processing or attacks. Embedding watermark in wavelet domain has been researched in resent years.The basic concept and theory of digital watermarking is first described in this paper. According to the different ways of information hiding, the existing algorithms of digital image watermarking are concluded and compared. Based on the shortcoming of the existing algorithms, we propose two novel watermarking algorithms in wavelet.A Multipurpose Image Watermarking is proposed. The algorithm improved, multipurpose method is proposed where the authentication watermark and the robust watermark are embedded in the wavelet transform domain for copyright protection and content authentication sometimes. Through a series of experiment, supportive evidence is provided to demonstrate the proposed method being effective in image authentication and image processing attacks.Another algorithm is proposed on improved robust blind watermarking algorithm in wavelet domain. Robust watermark is used for the protection of intellectual property rights of multimedia. The algorithm presents a robust adaptive image watermarking scheme. Increasing watermark security, key is used for the choice of embedded location, and only a pair of requirements of the embedded image blocks is being discrete wavelet transform, This algorithm complexity is only Determined to the watermark capacity, has nothing to do with the host image. So the scheme reduces the computational complexity relatively. Threshold strategy is used in embedding and extraction Process. In order to further increase the robustness of the program, the algorithm use genetic algorithm to optimize the threshold. Experimental results show that this scheme has a good transparency and good robustness to common image processing.At the end of this paper we have a prospect of the technique of digital watermarking. The extensive application in the future of the watermarking technique also attracts more watermarking algorithms.