Subdivision Surfaces Digital Watermarking Engineering Research

With the rapid development of computer and network technology, dissemination and exchange of digital media information (including text, image, audio frequency, video frequency, and three-dimensional model) become more convenient and quicker. But the undesirable side effects are obvious: the unauthorized redistribution of the copyrighted multimedia data loss of fidelity. Digital watermarking,which provides a scheme for copyright protection of digital media,has become a hot spot in the research field of multimedia data security in recent years.Digital watermarking is one kind of new information hiding technology and it confirms the ownership of the data through embedding secret information to original data. The embedded watermarking may be a paragraph of text, labels, serial number and so on. Watermarking is normally invisible or unconscious,This paper takes the subdivision surface digital watermarking technology as the study object, on the basis of concluding development background of digital watermarking and the framework of the basic theoretical proposes an effective blind watermarking subdivision surface algorithm and dose something useful to explore and try application of subdivision surface digital watermarking technology in the copyright protection of CAD product.The major work in this paper is listed as follows:First, on the basis of looking up a large number of domestic and foreign literatures which are about the digital watermark, introduces the basic concepts about the digital watermarking, as well as the main feature summers up the current domestic and international study status and development dynamic about three-dimensional model digital watermarking technology and subdivision surface digital watermarking technology.Second, it discusses basic principle, essential feature, typical algorithm as well as model watermark attacking method of. Digital image watermark technology and three-dimensional model digit watermark technology.Then, this paper expounds basic principle of subdivision surface, typical subdivision pattern and basic principle of subdivision surface digital watermarking algorithm. This paper proposed a subdivision surface digital watermarking algorithm, the watermarking signals were embedded into Geometric properties invariants subdivision surface to improve the robust. Firstly, the original meshes were subdivided three times and the model was transformed to an affine invariant space. Secondly, a 1D signal was produced through calculating the distance from the object center to the vertices, and performed wavelet transform on it, then embedded the watermark by changing the high frequency coefficients. Finally new subdivision surface was produced through inverse wavelet transforming.Then, it discusses application of subdivision surface digital watermarking in the CAD product copyright protection, introduces characteristic of the CAD product and application of subdivision surface in CAD. This paper proposed a subdivision surface digital watermarking algorithm which suits CAD product model.