Imperceptible Watermarking Scheme for 3d Triangular Mesh

The proposed method for watermark insertion in 3D polygon mesh is based on its geometrical properties. In this method selected vertices (geometrical attribute) are shifted from its original position. The changes in position of vertices w.r.t. original position is considered as watermark. The selection of vertices for shifting from their original position is dependent on the number normalization property of the vertices. The Cartesian coordinate of vertices are converted into spherical coordinate. The vertices are shifted from its original position by displacing vertex normal distance (ρ) component of (ρ,θ,φ) spherical coordinate of vertices. The watermark information is uniformly distributed through out the surface of 3D mesh. The shifting of vertices are done to establish a tradeoff among payload, robustness, security and quality. The proposed scheme is evaluated against distortion attacks.