Research Of Multifunction Digital Image Watermarking Algorithm

As the rapid development of the Internet, a variety of digital media such as documents, images,audio, video, etc., can be more easily spread and shared, but it also may be subjected to moreattacks. Digital watermarking is a kind of technology to protect the copyright of digital media,identify true and false. It can effectively ensure the security and integrity of the media. As animportant branch of digital watermarking, image watermarking has become a research hotspot inInternet age. This thesis targets at multifunction of digital image watermarking, studies twomultifunctional watermarking algorithms which can realize image copyright authentication, tamperlocalization and recovery. The main research works and innovations are as follows:1. Systematically introduces the background of digital watermark image, the specific conceptsand research status at home and abroad. Focuses on digital watermarking principle, evaluationmethods, and different kinds of attacks applications, advantages and disadvantages, and classifiedintroduces several classical watermark algorithms.2. Combining the discrete cosine transform(DCT) and lifting wavelet transform(LWT), thisthesis proposes a multifunctional blind watermarking algorithm for image copyright protection,content authentication and recovery. The algorithm embeds robust watermark in the DCT domainfor copyright protection, embeds fragile watermark and recovery information in lifting wavelettransform domain. Simulation results show that the algorithm has good invisibility. For normalattacks (such as adding noise, filtering, JPEG compression, etc.) and geometric attacks (such asshear, scaling, etc.), the algorithm has good robustness, can detect and restore the subtle alterationof the image.3. Proposes a multifunctional watermarking algorithm for image copyright protection, contentauthentication, and tamper recovery. In the wavelet domain, the algorithm embeds robustwatermark by singular value decomposition(SVD) transform to protect copyright; extracts waveletlow frequency sub band, segment it into blocks, after DCT transform, quantization and coding tomake the image have the ability of self-recovery, then code this information and fragile watermarkand embed it in LSB. Experimental results show that the algorithm has good visual effects, robustwatermarking, fragile watermarking and recovery algorithm has good performance.