Digital Image Watermarking Algorithm Based On Dwt And Svd

With the rapid development of the Internet, people easily get multimedia data from the network, but at the same time, the copyright protection of the issue has brought new challenges. Digital watermarking technology is a method by which a copyright information can be embedded in multimedia data, which has been applied to solve this problem. The research about secure and robust watermark technology is a challenging research, which has a broad prospect.The focus of this article is the watermark security and robustness. This article analyzes the singular value of the wavelet band in detail, researches the watermark encryption technology by using Arnold encryption, and presents two watermarking algorithms by modifying singular value coefficients in the wavelet low-frequency sub-band:1. The embedding and extraction image watermark algorithms based on DWT and SVD.The algorithm uses wavelet transform's good stability and shielding in the vision, combines with the character of singular value's smaller changes after attacks, finds the digital watermark algorithm based on the discrete wavelet transform and singular value decomposition. The amount of embedded watermark information directly impacts on a watermark's transparency, so that it only embeds the watermark singular value in the image. It can enhance the transparency of the watermark, so that it improves the robustness of the watermark. Based on the algorithm, the article operates a number of attack experiments. Simulations show that the new watermarking algorithm is feasible. It can maintain the image's good quality. Watermarks are not visible, and can resist most of the attacks. The watermark has good robustness.2. The wavelet domain watermarking algorithm based on encryption and SVD. On the basis of deeply studying the image scrambling technology, according to Arnold encryption algorithm based on the gray image, the watermark image is scrambled, and then SVD, the singular value is embedded in the singular value of the n-class low-frequency band of the image after the wavelet transform, in order to embed watermark in the singular value. Through experiments, it shows that the algorithm is robust. It can resist many common image processing attacks (such as filtering, cropping). Experiments show that the algorithm has the advantages, such as high efficiency, small operation, good security.