A robust DIBR 3D image watermarking algorithm based on histogram shape

Depth-image-based rendering (DIBR) has become an important technology in 3D displaying. Since either of the center image and generated virtual images might be illegally distributed, we need to protect both of the two kinds of images. In this paper, a histogram shape based watermarking algorithm is proposed to protect the DIBR 3D images. To make the watermarking method robust to common attacks, a pixel mean value based pixel groups selection method is presented to select several suitable pixel groups for watermark embedding. To solve the problem that the dividing of pixel groups can affect the performance of watermark extraction, the width of pixel group is determined by the maximum difference of pixel mean value between the original and attacked images. By this way, the watermark can be extracted with lower bit error rate (BER) from the attacked watermarked image. As the experimental results shown, the proposed method is much more robust to the geometric attacks and combined attacks compared with existing methods. In addition, the proposed watermarking method also has good robustness to the adjusting of baseline distance and depth image blurred.