Abstract
This paper presents two robust hybrid watermarking techniques for efficiently securing the transmission of the Three-Dimensional High Efficiency Video Coding (3D-HEVC). The first watermarking technique is the homomorphic-transform-based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The second technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. The objective of the two proposed hybrid watermarking techniques is to increase the immunity of the watermarked 3D-HEVC to attacks and achieve adequate perceptual quality. Also, we propose a wavelet-based fusion technique to combine multiple depth watermark frames into one fused depth watermark frame. Then, the resultant fused depth watermark is embedded in the 3D-HEVC color frames using the two proposed watermarking techniques to produce the watermarked 3D-HEVC streams. The proposed techniques reduce the required bit rate for transmitting the color-plus-depth 3D-HEVC data. The performances of the two proposed watermarking techniques are compared with those of the state-of-the-art watermarking techniques. The comparisons depend on both subjective visual results and objective results: the Peak Signal-to-Noise Ratios (PSNRs) of the watermarked frames and the Normalized Correlation (NC) of the extracted watermark frames. Extensive simulation experiments on different standard 3D video sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed watermarking techniques achieve not only very good perceptual quality, appreciated PSNR values, and saving of the transmission bit rate, but also high correlation coefficients, and high robustness in the presence of attacks. Furthermore, the proposed techniques improve both the capacity of the embedded information and the robustness without affecting the perceptual quality of the original 3D-HEVC frames. Indeed, the extraction of the fused and multiple primary and secondary depth watermark frames is possible in the presence of different attacks.