Research And Realization On Watermarking Algorithms For Digital Copyright Protection And Authentication

With the rapid development of network transmission and communication technology, the distribution, copying and editing on network multimedia is becoming increasingly common, and thus providers are increasingly strong demand to protect their digital contents, copyright issues have obtained more and more attention. Digital watermarking as one of the effective means for achieving copyright protection and authentication has become a hot spot in the multimedia information security field. But as a technical system, digital watermarking is not perfect. At the same time, most of the watermarking algorithms studied at present are implemented on the PC machine. As the growth of calculation amounts and complexities on digital watermarking algorithms, a high-speed computing device is urgently needed to perform computing tasks. DSP is undoubtedly an effective means.Watermarking algorithms for copyright protection usually require good stability and robustness. The airspace watermarking algorithm based on Chaos and spread-spectrum technology is proposed, which produces the watermark sequence through the chaotic map, and then embeds the watermark into the frequency-hopping sub-image. The experimental results show that the algorithm has strong robustness on filtering, noise, shear and other attacks. At the same time, the watermarking algorithm based on integer lifting wavelet transform is also proposed, which do the blocked lifting wavelet transform for the original image, and then the watermark sequence generated by direct-sequence spread spectrum is embedded into the fixed-frequency sub-band. The algorithm is able to resist a variety of common image processing attacks, and has good invisibility.Watermarking algorithms for copyright authentication usually require resisting some common image transformations, and are vulnerable to the malicious attacks. Digital watermarking algorithm based on chaos and scrambling is proposed. The algorithm uses the grayscale average of the original image to generate watermark, and then the watermark is embedded into the image after the scrambling. At the same time, the SVD-based fragile authentication watermarking is proposed. The original image is blocked to do the singular value decomposition, after that the XOR is carried on between singular value related sequenccs and chaotic sequences, and then the watermark is embedded in the original image. These two algorithms are both the fragile watermarking algorithms based on original image contents.In this paper, the DSP system realization for digital watermarking algorithms is also researched. Taken the Watermarking algorithm based on integer lifting wavelet transforms for example, the entire implementation process and the required attention are described detailedly.