Abstract: In order to protect the copyright information of 3D model data, a blind watermarking method based on Logistic chaotic encryption is proposed. Firstly, the binary image generated by dot matrix font is used as watermark information, and the watermark image is scrambled and encrypted. Then, the mesh simplification method is used to display the 3D mesh model in multiple layers, and the local set area of each vertex in the middle layer is calculated, and then the watermark information is embedded by modifying the small and dense vertices in the middle layer. Finally, the watermark strength is adaptively embedded according to the curvature of the neighborhood of the vertex. Watermark extraction is the  inversion process of watermark embedding. Experimental results show that the algorithm is robust to affine transformation, simplification, and smooth attacks, which not only achieves the purpose of protecting the copyright of the three-dimensional model, but also improves the security of the watermark system.

Key words: three-dimensional model, chaotic encryption, grid simplification, local set, blind watermarking