The Algorithm And Implementation Of Digital Watermarking Based On Improved SVD

Digital watermarking is a potential technology, which can solve the problem of multimedia copyright protection etc. One of the main parts of digital watermarking research is about algorithm research. Usually, the watermarking algorithm contains the process of embedding and watermark detection. Normally the general watermarking methods on transform domain become more and more popular, due to its good robustness and resistance to image compression, image filtering and noise etc. While the merit of those algorithms based on spatial domain is simple and fast, together with relatively less robust.We introduce a transform domain watermarking algorithm based on SVD. It has good robustness. In this paper, we describe the principle of this algorithm in detail .With our new algorithm, The intensity of the watermark to be inserted can be adjust easily, and multi-bits watermark information can be embedded into one image and according to the quality of the image which contains the watermark information, the robustness and capability of watermarking can be adjusted easily. Experimental results show that the SVD algorithm is robust against some image processing operations.But based on SVD, along with the enlarging of its size, more time will be spent in computing the SVs, and experiments show that the distortion in the diagonal direction is conspicuous, due to the calculation error, so we present a watermarking algorithm based on Block-SVD, we alse improve on it to add distortion compensation. In this method, the original image is divided into several blocks and the size of each block is 8-by-8. In watermark detection, we propose the idea of detector compensation to distortion. Extensive experiments show that the new method is very robust against image distortion. Based on the quick embedding, for the aspect of big images, such as complicated circuit diagram, mechanical drawing and architectural drawing, we believe it is a promising watermarking technology. At last the method based on Block-SVD is compared to the traditional Cox method, which also shows that the new method is very robust.At last, we realize the process of watermark casting and watermark detection under Microsoft Visual C++ MFC environment. Experimental results show that the designed watermarking system works well.