An image zero-watermarking scheme based on visual cryptography utilizing contour-wavelet
Yin Cao-qian · Journal of Optoelectronics·laser · 2009
To achieve the copyright protection of digital image,a zero-watermarking scheme based on visual cryptography(VC) is proposed.Firstly,a novel multiscale geometric analysis(MGA): contour-wavelet transform(CWT) is implemented;then in the transform domain,the coefficients are selected properly from the mid-subband which has the largest energy;finally,the zero-watermark signal is constructed by concealing the binary watermark into two shares according to the selected coefficients and a predefined VC codebook.The experimental results show the proposed scheme protects the copyright of digital image without modifying the host image,and it has quite robust against common image processing attacks such as JPEG compression,cropping,noise adding,sharpening and rotation.