Copyright Protection for Digital Colour Images Using Dual Watermarking Technique by Applying Improved DWT, DCT and SVD

Abstract

The main objective of the majority of research in Digital Image Watermarking technique is to improve the robustness of attacks.In this paper, a new algorithm has been proposed based on Discrete Wavelet Transform, Discrete Cosine Transformation in association with Singular Value Decomposition for embedding the dual watermark which provides an efficient copyright protection.Here the primary watermark is embedded into the secondary watermark and the resultant image is used as a watermark for the host or cover image. The primary and secondary watermarks are retrieved back by using an efficient watermark retrieving algorithm. During the processes of embedding the scaling factor is varied to improve the quality of watermarked image. In this proposed algorithm the watermarked image is extracted back with same quality, high peak signal to noise ratio and normalized correlation coefficients. The quality of the extracted watermarks is authenticated using Peak Signal to Noise Ratio and Normalized Correlation Coefficient. Compared with previous methods the proposed algorithm has a significantly higher robustness against various geometrical and removal attacks.Nearly 28 attacks like Cropping, Rotating at various angles, Sharpening, Motion Blur, rescaling, resizing and adding noise like Salt and Pepper noise, Gaussian noise, Spackle noise, filters like average filter, median filters are attempted. Even after attempted all such attacks both the watermarks are retrieved back with the same quality and high normalized correlation coefficient.