Research On Technology Of Reversible Watermarking In 3D Mesh Model

In recent years,with the rapid development of 3D model-aided design and cloud manufacturing technology,3D models have been rapidly popularized.Compared with other digital products,the three-dimensional grid model covers more important information,and often faces security threats,such as data leakage,malicious tampering,and copyright disputes.How to more effectively prevent the infringement of 3D models has become a hot research topic in academia.Firstly,this paper systematically introduces the research status of digital watermarking of 3D mesh model,and then summarizes the data structure characteristics of three-dimensional mesh model,as well as the characteristics and evaluation indexes of visible reversible watermark and encrypted domain reversible watermark.Based on the characteristics and application requirements of the threedimensional mesh model,this article has carried out research on the reversible watermarking technology of the 3D mesh model,and obtained the following research results.(1)A visible reversible watermarking algorithm for 3D mesh models based on mesh subdivision is proposed.The algorithm projects the smooth area of the 3D mesh model to a 2D plane for clipping and subdivision.Then embedded the index as a reversible watermark into the carrier containing the visible watermark.The watermark is closely integrated with the carrier,and operations such as translation,rotation,scaling,mesh subdivision,and mesh smoothing on the model will not destroy the visible watermark.According to public documents,this scheme is also the first visible reversible watermarking algorithm for 3D mesh models.(2)A reversible watermarking scheme based on homomorphic encryption and direction vector in the encrypted domain of 3D model is proposed.This method first preprocesses the original 3D model,and then uses the Paillier cryptosystem to encrypt the vertices of the 3D model.Then divide all the vertices of the 3D model into an embedding set and a reference set,and use the reference set to calculate the prediction error of the vertices in the embedding set.Then establish the mapping table,get the direction vector according to the mapping table,and use the direction vector to expand the direction of the prediction error to embed the secret data.Finally,the secret data is extracted by comparing the angle between the prediction error and the direction vector,and the reference set is used to restore the original model.Compared with the existing reversible watermarking algorithms in the encryption domain of 3D models,this method can resist RST attacks and the embedding capacity is higher.(3)Based on Open GL and Microsoft basic class library,with Visual Studio 2017 as the integrated development environment,a 3D model digital watermarking system was designed and implemented.