Research on image digital watermarking based on wavelet transform and grey relational analysis

A digital watermark technique based on the wavelet transform is presented in the paper. To ensure the security of the watermark image, the watermark image is scrambled before embedding. According to the characteristics of the multiresolution decomposition of the wavelet transform, the watermark values in different directions and subbands are added by various intensities to the corresponding directions and subbands of the original image. Finally, the experiment results show that the similarity between the extracted watermark and the original watermark is high by adding noise, rotating and geometric attacks.