Research On Digital Watermarking Technologies For 3D Mesh Models

The information exchange based on computer networks has provided great convenience to the usage and spreading of the digital multimedia products. However, the digital products can be illegally copied and tampered with ease, which makes the information security and copyright protection become a practical problem needed to be solved urgently. Digital watermarking technology provides digital products with an efficient measure of copyright protection. Current digital watermarking technology mainly focuses on image, video and audio data, in contrast, the research on the watermarking of 3D mesh models has obtained less attention from researchers. Along with the rapid development of 3D data in the area of information technology, more and more CAD-based 3D data is entering into the World Wide Web, therefore, 3D digital products will also face copyright-related problems. We urgently need a measure to prevent the 3D digital products from unauthorized users. Accordingly, 3D digital watermark will play more and more important role in the field of copyright protection.In the thesis, the basic principle and the domestic and oversea research status of digital watermarking technology are introduced briefly, such as, the basic concepts, the category method, the representative algorithms and the attacking measures. Based on the theoretical research of singular value decomposition (SVD) and geometry signial processing, and through making use of comprehensive planar parameterization, a novel digital watermarking algorithm based on SVD for 3D meshes model is proposed in this thesis. Firstly, the planar parameterization is adopted to transform the 3D meshes into planar mesh signals. Secondly, uniform grid sampling is applied to the 2D mesh signals to generate regular sampling signals. Thirdly, singular value decomposition is applied to the regular sampling signals and the watermarking information is embedded into it. Finally, the watermarked 3D meshes model is produced via contrary operation mentioned above. Because the SVD technique is applied into 3D meshes model, the secrecy of the watermark is enhanced, and the robustness of the watermarked image is to be very strong, which accomplish theobjective of copyright protection. At last, the experimental results of the algorithm are given to test the robustness of algorithm proposed in this thesis.Tremendous experimental results are presented in the thesis, and the results prove that the digital watermarking algorithm proposed in this thesis is unperceivable and shows great robustness against a variety of attacks such as rotation, nosing, dithering, multi-resolution filtering, mesh cropping and sorts of combination attacks.