Research On Digital Watermarking Algorithm Based On 3D Point Cloud Model

With the maturity of 3D printing technology,digital products of 3D models have a broad application prospect,which are now mainly concentrated in the fields of military,medical,modeling indoor scenes and unmanned aircraft,bringing great convenience to all aspects of people’s lives.In addition,the wide coverage of 5G communication technology also makes the data transmission of 3D models more convenient,which makes it easier for unscrupulous elements to obtain key information,thus triggering piracy,infringement and other copyright problems,making it more difficult for 3D model digital products to get further development.The use of digital watermarking technology to protect the copyright information of 3D models has become a key research area,in which some research results have been achieved on 3D mesh models.However,there is little research on 3D color point cloud models,which leads to the urgent need to solve the problem of copyright protection for 3D color digital products.Therefore,this thesis researches the copyright protection of digital products of3 D color point cloud models by using digital watermarking technology,and the main work is as follows:(1)For the problem of copyright protection of 3D color point cloud models,a digital watermarking algorithm based on redundant discrete wavelet transform and singular value decomposition is proposed.Firstly,the 3D affine invariant processing algorithm is used to pre-process the 3D color point cloud model so that the 3D color point cloud model can effectively resist the attacks of translation,rotation and uniform scaling;secondly,the coordinate projection algorithm is used to planarize the 3D color point cloud model after affine invariant processing to obtain the 2D color image;then,the redundant discrete wavelet transform is performed on the 2D color image to obtain the lowfrequency coefficients.Then,the watermark embedding is realized by embedding the elements obtained from the singular value decomposition of the binary watermark image into the low-frequency coefficients;finally,the 3D color point cloud model with watermark is obtained by using the point cloud reduction algorithm.(2)Aiming at the problem of insufficient key space and weak robustness,an adaptive digital watermarking algorithm based on Gyrator transform is proposed.First,the 3D color point cloud model is converted into 2D color image,based on which the optimal embedding region is obtained for the 2D color image using the absolute contrast function;then,the Gyrator transform is performed on the binary watermark image to encrypt the watermark image,and the encrypted watermark image is embedded into the optimal embedding region to realize the watermark embedding.Finally,the 3D color point cloud model with watermark is obtained by using the point cloud model reduction algorithm.(3)Design and development of digital watermarking system for 3D color point cloud model.According to the requirements of copyright protection of3 D color point cloud model,based on the above work,this thesis designs and develops a human-computer interactive digital watermarking system.The system integrates the two algorithms proposed in this thesis,selects the appropriate digital watermarking algorithm according to the needs of users to achieve the purpose of copyright protection.This system contains watermark embedding and extraction module based on RDWT transform and SVD decomposition,adaptive watermark embedding and extracting module based on Gyrator transform,3D model visualization and interaction module and simulation attack module of 3D model.The test results show that this system operates correctly and has certain practicality.