Image adaptive and high-capacity watermarking system using accurate Zernike moments

The authors propose a novel image adaptive watermarking scheme for geometrically invariant and high-capacity data embedding scheme based on accurate and fast framework for the computation of Zernike moments (ZMs). The high capacity is achieved by maximising data embedding size and improving the hiding ratio after reducing the inaccuracies in the computation of ZMs. Furthermore, they also introduce a concept of conditional quantisation technique which enables to reduce the total number of ZMs needed to be modified during watermark embedding. This concept enhances the visual imperceptibility of the watermarked image and its robustness against various attacks. Numerous experiments have been performed to demonstrate the improvements in embedding capacity, visual imperceptibility, watermark robustness and time complexity as compared with the existing methods.