Perceptual digital watermark of images using wavelet transform

A perceptually based watermarking technique for an image is proposed. Based on the just-noticeable difference model in the wavelet domain, the watermark is inserted in the wavelet coefficients and its amplitudes are controlled by the wavelet coefficients so that watermark noise does not exceed the just-noticeable difference of each wavelet coefficient. Meanwhile, the order of inserting watermark noise in the wavelet coefficients is the same as the order of the visual significance of the wavelet coefficients. Hence, our approach is adapted with the image content and transparency, and the robustness of the digital watermark can be guaranteed. Experimental results show our approach has excellent performance in the quality of the watermarked images and the robustness of the watermark.