Video Watermarking Technique using Visual Sensibility and Motion Vector
Mariko Nakano-Miyatake, Hector Perez-Me · InTech eBooks · 2010
The proposed algorithm performs watermark embedding and detection during MPEG-2 coding process, in which firstly an adequate embedding energy is computed using the HVS based three criteria: sensibility of different color channels (red, green and blue channel), sensibility of spatial region with different features, such as plain, texture and edge regions, and finally sensibility of regions with different motion speed. Due to the lower sensibility of the HVS to blue channel, the watermark embedding is carried out only in blue channel. And using the latter two criteria, an adequate watermark embedding energy is assigned to each block of 8×8 DCT coefficients of I-frames and P-frames. In the proposed algorithm, B-frames are not used for watermarking in order to reduce watermark embedding and detection time. The proposed algorithm was evaluated from watermark imperceptibility and robustness points of view. The watermark imperceptibility was evaluated using the PSNR and Universal Quality Index (UQI). Both values show the watermark imperceptibility of the proposed algorithm, especially perceptual distortion evaluated using UQI shows that the watermark is imperceptible by the HVS. To evaluate the watermark robustness against some common attacks including video frame attacks such as: frame dropping, frame swapping and frame averaging. The simulation results show the watermark high robustness to above mentioned attacks. Also the proposed algorithm is compared with other algorithms with similar objective; the comparison results show that the proposed watermarking algorithm is more robust against a wider range of attacks than other watermarking algorithms. The additional processing time to the MPEG-2 standard coding caused by watermarking is also measured. Since in the proposed algorithm, watermarking is carried out only in the Iframes and P-frames, the overall additional time is less than 10% of the MPEG-2 standard coding. Therefore we can conclude that the proposed watermarking algorithm is suitable for a real implementation.