Hybrid Watermarking Technique for Data Hiding in RGB Images

Digital watermarking is nothing but the technology in which there is embedding of various information in digital content which we have to protect from illegal copying. This embedded information to protect the data is embedded as watermark. In digital watermarking, a watermark is embedded into a cover image in such a way that the resulting watermarked signal is robust to certain distortion caused by either standard data processing in a friendly environment or malicious attacks in an unfriendly environment. Beyond the copyright protection, Digital watermarking is having some other applications as fingerprinting, owner identification etc. Digital watermarks are of different types as robust, fragile, visible and invisible. In this work, a comparative analysis of two most recent techniques used in digital image watermarking; they are DWT and hybrid DWT-SVD. Both these techniques are very much robust and imperceptible. In case of DWT, decomposition of the original image is done to embed the watermark and in case of hybrid DWT-SVD firstly image is decomposed according to DWT and then watermark is embedded in singular values obtained by applying SVD. Here, the techniques are compared on the basis of PSNR value at different values of scaling factor. For implementing the above digital image watermarking techniques, MATLAB R2013a is used.