An adaptive watermarking technique for context sensitive images to create high quality watermarked images

摘要

Watermarking is an important technique used for proprietary content management. The technique has been widely studied and evolved according to the content. But as of now there has been no technique proposed to adapt the scaling factor for watermarking an image on a cover image, which can reduce the noise, and increase the structural similarity of the watermarked image. From the literature it is found that Particle Swarm Optimization (PSO) is a less complex metaheuristics optimization algorithm which is the desired property for application to the current problem of adaptive scaling. Hence, in this paper, PSO has been proposed for adaptively finding the scaling factor which is sensitive to the cover image. Moreover, Redundant Discrete Wavelet Transform (RDWT) is available for analysis of image with a single color. In this paper a generic Chroma Redundant Discrete Wavelet Transformation Technique (CRDWT) is proposed which can be applied to color images also. Performance metrics such as, Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index (SSIM) are used to evaluate the imperceptibility and Normalized Cross Correlation (NCC) is used to test the robustness of the watermarked image against attacks. Experimental analysis shows that the CRDWT is almost 30% efficient and more robust with NCC value in the range of 0.5 to 1.0.