Research Of 3d Digital Product Copyright Protection System Based On Watermarking Technique

With the rapid development of multimedia and the globalization of Internet, the protection of multimedia data copyright is becoming more and more notable. It becomes more important for 3D digital products which contain much of the hard work of their designers. Watermark is a technique which can hide information such as copyright or something else which can tell its adscription to certain media data. It adds protected information into the digital product using the sense redundancy trait of mankind through signal processing. It provides clues for copyright protection, tracing, integrality and some other fields.Based on the research of 3d model watermarking, combining with the requirement of copyright production on watermarking, the 3D digital product copyright protection system based on watermarking technique is raised. The main content of each segment in the system and the critical technique involved are described.Then, according to the high precision trait requirement of some 3D models and in some occasions, especially for exhibition, the 3D models are exhibited by their 2D images (images obtained after projection of 3D models) more than 3D models themselves, an affine invariant 3D model watermark algorithem based on mesh subdivision and a 3D model's silhouette watermark algorithem are proposed. Based on mesh surface subdivision, the former insert watermark information using the affine invariant trait of Nielson norm and the representation redundancy of 3D model files; extends exited 2D contour watermarking technique, the latter insert the watermark representing model's copyright in the 3D model apparent contour, and the watermark can under certain conditions be extracted from 2D views of the model in which watermarked contour information is present. Algorithems are proved by experiments robust against many attacks.In the end, using OpenGL, with the detailed design of each segment in the copyright protection system, the implementation of 3D digital product copyright protection system based on watermarking is present.