A novel watermarking for DIBR 3D images with geometric rectification based on feature points

Depth-image-based rendering (DIBR) has become an important technology in 3D displaying with its great advantages. As a result, more and more 3D products copyright problems turn out. Since either the center view with depth image or the synthesized virtual views could be illegally distributed, we need to protect not only the center views but also the synthesized virtual views. In this paper, a robust watermarking method for DIBR 3D images is proposed. After applying three-level DWT to the center image, we utilize spread spectrum technology to embed the watermark into suitable coefficients of the sub-blocks of the center image, by this way we make our method robust to typical signal distortions, such as JPEG compression, noise addition and median filter. Meanwhile, in order to make the proposed method robust to some common geometric distortion attacks, SIFT-based feature points are used for geometric rectification to eliminate the effect caused by geometric distortion attacks. As the experimental results shown, the proposed method is much more robust to the common signal distortion attacks with lower BER (bit error rate) compared with existing methods. With geometric rectification, our method also performs good robustness to some simple affine transformations. In addition, the proposed watermarking method also has good robustness to the common operations of DIBR processing system.