Reversible Watermarking Of Color 3D Mesh Model

With the rapid development of science and technology,the quality of people's life continues to improve.Two-dimensional pictures can no longer meet people's visual and application needs,so three-dimensional mesh models have emerged at the historic moment and have been widely developed in recent years.The development of the Internet has also promoted the spread of the three-dimensional mesh models,and at the same time,security issues have also received attention.For digital three-dimensional mesh models,we need to apply digital protection,namely digital watermarking.Digital watermarking technology is an important copyright protection technology,which can play the role of copyright protection by embedding watermark information into the three-dimensional mesh models.Reversible watermarking technology is the most commonly used method of digital watermarking technology.Because the reversible watermark technology can extract the watermark information in the model and restore the original model,it not only plays the role of copyright protection,but the original model can still be used.However,the existing reversible watermarking algorithm of 3D mesh model not only has the disadvantage of low embedding capacity,but also only aims at the colorless 3D mesh model.With the wide application of the model,the color 3D mesh model is used more.In response to the above problems,this thesis mainly does the following work:(1)In this thesis,the color three-dimensional mesh model is used as the original carrier model.The model covers the vertices and color information.The vertices are important information that constitute the three-dimensional mesh model.First,we embed watermark information on the vertices of the color 3D mesh model.The vertex coordinates are predicted by the topological structure between vertices.Since the vertex coordinates are represented by decimal points,we do not need to consider the overflow situation,and each vertex can be embedded as the embedding point in the watermark information.The algorithm can not only extract hidden information completely,but also restore the original carrier model without distortion.(2)This thesis not only embeds the watermark information of the vertices,but also uses the color information of the color 3D mesh model as carrier.In this thesis,the algorithm of prediction error expansion is used to embed watermark.The color embedding of the color three-dimensional mesh model is the same as the embedding of the two-dimensional image.The pixel values have a certain range,and the overflow problem needs to be considered.This thesis avoids the overflow situation by modifying the histogram.In order to verify the algorithm in this thesis,experiments on feasibility and embedding capacity are conducted.The experimental results show that the algorithm in this thesis is feasible,and the amount of embeddable information can be improved by using the algorithm.