A Robust High-Capacity Affine-Transformation- Invariant Scheme for Watermarking 3D Geometric Models

In this article we propose a novel, robust, and high-capacity watermarking method for 3D meshes with arbitrary connectivities in the spatial domain based on affine invariants. Given a 3D mesh model, a watermark is embedded as affine-invariant length ratios of one diagonal segment to the residing diagonal intersected by the other one in a coplanar convex quadrilateral. In the extraction process, a watermark is recovered by combining all the watermark pieces embedded in length ratios through majority voting. Extensive experimental results demonstrate the robustness, high computational efficiency, high capacity, and affine-transformation-invariant characteristics of the proposed approach.