Multiple Digital Watermarking Research And Implementation

Digital watermarking protects the copyright and content authentication by embedding some digital products, which should not influence the quality and content of the original digital products obviously. Multiple watermarking on the basis of single watermarking is concerned by more and more researcher,which can solve the problems of multiple copyrights, copyright certification at different stages and so on. We made the follow corresponding research on the image and audio multiple watermarks.1,A superior position multiple color image watermarking algorithm based on DWT was proposed, which combines with the good time-frequency local characteristics of DWT and the geometric distortion invariance of singular value decomposition (SVD), embedding two watermarks which have different ability to against many attacks and have complementation.2,Using the orthogonal principle of hadamard transform, four color watermarking images combine into one imbedding watermark. It breakthrough the problem of information quantity by embedding four watermarking information. A four color image watermarking algorithm using hadamard transform and SVD in DWT and DCT domain is proposed.3,Combining the multi-resolution character in DWT domain and the steady positive-negative sign of the DC coefficient in DCT domain, transform audio signal into matrix and imbed two watermarks. In this paper, two multiple audio watermarking algorithms are proposed.In a word, according to the theory knowledge SVD, DWT, DCT and hadamard transform, above watermarking algorithms are proposed, which not only have the best invisible /imperceptibility, but also have stronger robustness, especially against shear, compare with traditional algorithm.