Research On Reversible Visible Watermarking Algorithm For 3D Model

With the development and popularization of network and information technology,digital files are easy to be misappropriated and tampered in the process of dissemination.Copyright protection of digital media files has become an urgent problem to be solved.At the same time,three-dimensional models are increasingly used in medical imaging,computer-aided design,mechanical design,manufacturing industry,virtual reality,and 3D movies,making the inevitable application of digital watermarking technology for 3D model files.The three-dimensional model digital watermark can be divided into visible watermark and invisible watermark according to transparency.According to its classification,this paper proposes a three-dimensional model visible watermarking algorithm and a three-dimensional model invisible watermarking algorithm.At the same time,a dual watermarking algorithm is proposed,which embeds visible watermark information and invisible watermark information into the one model.(1)A reversible 3D model visible watermarking algorithm is proposed.First,we select the smooth area of the three-dimensional model;Second,we project the smooth area onto a two-dimensional plane;Then,we overlap the two-dimensional array of watermark information with the smooth area to select the triangle patches to be subdivided;And finally,we record the triangle patches Subdivide to embed watermark.This algorithm can embed the watermark information into the smoothest region of the model,with less modification to the original model,and can restore the embedded watermark model to the original model.The algorithm can embed a variety of watermark information such as Chinese characters,English letters,numbers,and graphic signs on a three-dimensional model file.It can resist noise attacks and simplify attacks,and has certain robustness.At the same time,the embedded watermark information can only be displayed in the grid and point cloud formats,and the printed watermark 3D model cannot display the watermark information.(2)A 3D model information hiding algorithm based on feature verticesand triangles is proposed,which can also be called a blind watermarking algorithm.The algorithm uses feature points to locate the embedding position and order of watermark information,and uses the vertex ordering of triangles in the neighborhood of feature points to embed watermark information.The algorithm has robustness while guaranteeing a certain watermark capacity.(3)A double watermarking algorithm is proposed,which embeds two types of watermarking information into different regions of the model.The embedding process does not affect each other.The model embedded with double watermark can still extract blind watermark information more completely after the visible watermark is destroyed.