Copyright Protection for Holographic Video Using Spatiotemporal Consistent Embedding Strategy

The interest in a three-dimensional (3-D) holographic display is increasing daily because it can generate full depth cue without utilizing any special glasses. However, the content of 3-D holographic videos currently without any protection can be illegally distributed and maliciously manipulated. Therefore, there is an urgent need to protect the copyright of holographic videos against malicious copying. Since watermarking is an effective way to protect the ownership of holographic sequence, this paper proposes a spatiotemporal consistent embedding algorithm for the holographic video watermarking. Imperceptibility requirement in the holographic video watermarking is more challenging compared with static holograms because of the temporal dimension existing in videos. The embedding algorithm should not only consider spatially embedding strength for each frame of the video, but also take the temporal dimension into account in order to guarantee the visual quality of the moving object. Before embedding, to defend the imperceptibility of the watermark from the holographic moving object, the embedding parameters are evaluated by the salient object from the interframe and intraframe. Different from the previous video watermarking algorithm, in order to ensure the robustness, in our paper, instead of two-dimensional watermark, 3-D watermark converted data (QR code) are embedded in the cellular automata (CA) domains using 3-D CA filters. Finally, the QR codes can be extracted from the watermarked holographic frames, and the final 3-D watermark can be digitally reconstructed with different depths' cue using the computational integral imaging reconstruction algorithm. The experimental results demonstrate that the proposed method exhibits superior performance compared to several methods in the literature, especially the robustness against additive noise and compression attacks.