A reversible robust watermarking scheme based on two out of two visual cryptography approach

A reversible visual cryptography based robust watermarking scheme has been presented in this paper. Reversibility has been maintained in the scheme as such no changes are made into the cover image. The image information is obtained based on its homogeneity using the quadtree based decomposition setting a threshold criteria. Thereafter based on the largest singular values, features are obtained and classified using k-medoid clustering. A master share is thus obtained based on the clustering result which together with the secret image furnishes the ownership share. The ownership share thus obtained is managed by the certificate authority to verify the rightful ownership if any dispute arises in future. The robustness of the scheme has also been tested against comprehensive set of attacks and was found to be comparatively efficient as compared with the existing state of art approaches.