Adaptive watermarking schemes based on a redundant contourlet transform

We are interested in the adaptive watermarking approaches and in directional multiresolution image transforms. In this paper, a novel watermarking technique based on a redundant contourlet transform is presented. In contrast to the wavelet transform widely used for image watermarking, to our best knowledge, this is the first time contourlets are applied to this field. The goal of this work is to investigate whether the contourlet with their extra feature of directionality and the explicit introduction of redundancy would provide any significant advantages over the wavelets in terms of watermark robustness and invisibility. Our approach uses directional subbands to generate weighing masks that identify significant image features. The redundancy being introduced brings simplicity and accuracy for mask processing. To prove the validity of our approach, we give experimental results, compare our algorithm to a wavelet-based adaptive watermarking technique and assess watermarking performance in terms of robustness and invisibility.