A Visual Cryptography based Watermarking Scheme Incorporating the Concepts of Homogeneity Analysis and Singular Value Decomposition

Abstract

A visual cryptography based watermarking scheme incorporating the concepts of singular value decomposition (SVD) and the homogeneity analysis of the cover image is proposed here. Firstly, feature vectors are created from the singular values of the homogeneous blocks and thereby classified using the k-medoid clustering technique. A master share is then constructed based on the clustering result and thereafter, combined with the secret binary image (watermark) ownership share is build up. This ownership share is registered with the certificate authority in case to resolve any dispute regarding rightful ownership of the image in future. A two-out-of-two visual cryptography scheme is being used in the proposed methodology and robustness validated by applying comprehensive set of attacks. The peak signal to noise ratio (PSNR) and normalized cross correlation (NCC) metric values are used for evaluation of the scheme. Higher values of these metrics establish the appropriateness of the proposed methodology as compared to the other state of art schemes for copyright protection.