An Invisible Non-Blind Color Image Watermarking Scheme

Abstract

Watermarking in computer or information security, is a technique that embeds the copyright information of digital signals or digital identifier in the respective signals of the host to provide authenticity who the copyright owners are or to track from where the signal is originating. In general, an efficient watermarking technique must give two features: robustness and perceptual imperceptibility. In this thesis, a watermarking technique is proposed based on a new combination of Fast Curvelet Tansform (FCT), Robust Principal Component Analysis (RPCA) and Singular Value Decomposition (SVD). The gray-scale watermark logo is scrambled using Generalized Arnold Transform (GAT) to enhance the robustness and security. The original image is decomposed to low rank and sparse components using RPCA; the curvelet coefficients are obtained using FCT via Unequally-Spaced Fast Fourier Transforms (USFFT) to embed the processed watermark using SVD into the color image. The robustness and imperceptibility of the proposed technique is verified against a variety of processing operations (noise, filtering) and geometric attacks (crop, resize, projection etc.). In curvelet transform, fewer coefficients contain the most energy, also giving optimally sparse representation of the significant image features and edges that helps in efficient recovery of the embedded watermark even after severe image degradation. To verify the signicance of the proposed technique it is compared with state of the art existing watermarking technique. The quantitative and visual simulation results reveal that the proposed watermarking technique is efficient and provides high tolerance against geometric as well as normal image processing attacks as compared to state of art existing watermarking technique.