Based On Weight Of Vertex Watermarkingalgorithm And Optimization For 3D Models

5With the increasing of enrolment in application of computer network, the rapid development of three-dimensional scanning technology and three-dimensional model making tools, applications of three-dimensional model is becoming more and more popular in various fields (such as biology, chemistry, and engineering etc.). People can conveniently post their three-dimensional works, electronic transactions, research and download useful three-dimensional model works by the network. With the three-dimensional models are widely used in urban simulation, movie stunt, animation game production and military field, illegal possession of three-dimensional model, modified, and transmitted unauthorized infringement of product become more serious, and three-dimensional models'products such as the ownership, modification of the legal rights are destroyed seriously. Facing the increasingly serious copyright protection problems, we urgently need an effective technique to solve this problem. Three-dimensional model digital watermarking technology is a perfect method. The technology embedded the watermarking in three-dimensional model without influencing three-dimensional model's using and fidelity. It effectively solves the problem of the model copyright.Researching on home and abroad technology of three-dimensional digital model watermark, we can analyze the watermark technology system frame, describe in detail the watermark generation, embedding and extracting, and sums up the typical algorithms of three-dimensional model watermark. On these bases, this thesis mainly does the following several aspects work:First, the characteristics of OBJ format three-dimensional model is analyzed, through analyzing feature point in the regional of model and watermarking algorithm, I understand that the robust of watermark embedding algorithm has closely related with embedded positions. Based on this kind of thought, this paper proposes a new three-dimensional model watermark algorithm. It needs to calculate the weight of vertex to select vertex set, and embed watermark by modifying the value of X coordinates of these vertices and record the location of the watermark information by modifying the value of Z coordinates of the vertices.Second, genetic algorithm is used in two-dimensional digital image watermark technology. Through studied the theory of genetic algorithm, an optimized watermarking algorithm is proposed. It is described how to set the abstract value of concept such as chromosomes, fitness, genetic operator etc. in the optimization process. Those are for searching appropriate embedded position, and getting the optimal or satisfaction result sets, finally to improve ability against the attack and invisibility of three-dimensional model.Third, based on the algorithm, we have tested watermark by simulation experiment. The experimental results show that on the premise that this does not affect the using and fidelity of 3D model, the proposed method is not only robust to affine attack,but also robust against mesh cropping.