Robust contourlet-based watermarking for depth-image-based rendering 3D images

In this paper, we propose a new blind watermarking scheme for depth-image-based rendering (DIBR) 3D images. The center view and the depth map are available at the content provider side. After applying contourlet transform (CT) to the center view, we embed the watermark into the selected contourlet subbands of the center view by quantization on certain contourlet coefficients. The virtual left and right views are generated from the watermarked center view and the associated depth map using DIBR technique at the receiver side. The statistical differences between quantized and unquantized contourlet coefficients are used for watermark extraction. The watermark can be detected with a low bit error rate (BER) from the center view, the left and right views even when each view is distorted and distributed separately. The simulation results demonstrate that our scheme keeps good perceptual quality of the watermarked images under both objective and subjective image quality estimations. Moreover, compared with other related methods, the proposed scheme has better performance in terms of robustness against image compression, noise addition and geometric attacks such as rotation, scaling and cropping.