LAUSR

Aiming at reducing the large distortion of the existing reversible watermarking for three-dimensional(3D) mesh models and meeting the needs of authentication in cloud-based data storage, a semi-fragile reversible watermarking for authenticating 3D models in dual domains is proposed based on variable direction double modulation. A 3D model is first transformed into the spherical coordinate system, and then the direction of quantization modulation is changed under specific circumstances to achieve less distortion. Watermarks are determined by the relative position and vertices number in the one-ring neighbourhood of all vertices, so the watermark generation is independent of the coordinate system and robust to RST(rotation, scaling, and translation). In addition, the watermarks are generated and embedded in both plaintext domain and encrypted domain, and the authentication can be accomplished in both domains. Experimental results and analysis show that the proposed scheme can effectively detect malicious tampering in two domains and reduce the distortion caused by watermark embedding. It has potential application in the content authentication of 3D models in cloud-based data storage.