Digital Image Watermarking Scheme Based on Visual Cryptography and SVD

Imperceptibility, robustness and security are the most important parameters of a watermarking scheme and tradeoff between these parameters is a challenging task. In this paper, we propose a watermarking scheme to balance the tradeoff between security and imperceptibility by using visual cryptography and singular value decomposition (SVD). Watermark image is encoded into n shares using visual cryptography of shares scheme. Among the n shares any two shares belonging to qualified set of shares are chosen and embedded into U and V component of SVD. The unused shares are with the authorized owner which can be used to extract the whole watermark. This can be done by superimposing shares or bitwise logical AND operation with the binary shares extracted from U and V component of watermarked image. Moreover the U and V component of SVD are exploited to enhance the imperceptibility. Experimental results show that the proposed technique is imperceptible, secure and robust to the common image processing and other attacks.