This article proposes a stereo vision based digital watermarking scheme that uses regularized feature-based disparity estimation for copyright protection of stereo content. The watermark data are embedded into the right image of a stereo image using the discrete wavelet transform algorithm, and a disparity vector is extracted from the left and watermarked right images. The disparity vector and the left image are then transmitted to the recipient through a communication channel. At the receiver, the watermarked right image is reconstructed from the received left image and disparity vector by employing regularized feature-based disparity estimation. From the difference between the watermarked and original right images, the embedded watermark image can then be extracted. From experiments using the stereo image pair of "Fichier," "Tunnel," and watermark data of "3D," it was found that the peak signal to noise ratio (PSNR) of the reconstructed right image through the proposed algorithm can be improved by an average of 3.61 dB compared to those of a conventional algorithm. At the same time, the PSNR of the watermark image extracted from this reconstructed right image can also be improved by an average of 2.36 dB when the Quantizer Scale is given as 20.
Kyung-Hoon Bae, Dong-Choon Hwang, Eun-Soo Kim, "Stereo Vision Based Digital Watermarking Using Regularized Feature-based Disparity Estimation" in Journal of Imaging Science and Technology, 2008, pp 50503-1 - 50503-7, https://doi.org/10.2352/J.ImagingSci.Technol.(2008)52:5(050503)