DWT-based high-capacity blind video watermarking, invariant to geometrical attacks

The paper describes a high-capacity blind video watermarking system invariant to geometrical attacks such as shift, rotation, scaling and cropping. A spatial domain reference watermark is used to obtain invariance to geometric attacks by employing image registration techniques to determine and invert the attacks. A second, high-capacity watermark, which carries the data payload, is embedded in the wavelet domain according to a human visual system model. This is protected by a state-of-the-art error correction code (turbo code). For a false detection probability of 10/sup -8/, the proposed system is invariant to scaling up to 180%, rotation up to 70/spl deg/, and arbitrary aspect ratio changes up to 200% on both axes. Furthermore, the system is virtually invariant to any shifting, cropping, or combined shifting and cropping. The system is also robust to MPEG2 compression, even when combined with shifting and cropping.     

Turbo code protection of video watermark channel

The operational capacity of a watermark data channel is deduced by examining the correlation distribution at the retrieval end of a spread-spectrum-based watermarking system. This enables capacity to be determined given MPEG-2 compression, geometric attack, visual thresholds and channel coding. Watermarking itself is carried out in the DCT domain using video-dependent and visual perception concepts. An objective of the paper is to determine the capacity improvement provided by advanced FEC. It is found that FEC based on multiple parallel concatenated convolutional codes (3PCCCs) can give an order improvement in capacity for compressed video, and typically gives 0.5 kbit/s capacity under a combined compression-geometric attack     

Wavelet and multiwavelet watermarking

The main objective of the paper is to provide a like-with-like performance comparison between the wavelet domain and the multiwavelet domain watermarking, under a variety of attacks. The investigation is restricted to balanced multiwavelets. Furthermore, for multiwavelet domain watermarking, both wavelet-style and multiwavelet-style embedding are investigated. It was shown that none of the investigated techniques performs best across the board. The wavelet-style multiwavelet technique is best suited for compression attacks, whereas scalar wavelets are superior under cropping and scaling. The multiwavelet-style multiwavelet is far superior under low-pass filtering. On the basis of these results, it was concluded that for attacks which are likely to affect mid-range frequencies, the wavelets are more suitable than multiwavelets, whereas for attacks which are likely to affect low frequencies or high frequencies, the multiwavelets are the best choice. Furthermore, the multiwavelets generally offer better visual quality than scalar wavelets, for the same peak signal-to-noise ratio (PSNR). This suggests that part of the available channel capacity remains unused, and shows once more the potential of multiwavelets for digital watermarking.