# RST Resilient Watermarking Scheme Based on DWT-SVD and Scale-Invariant Feature Transform
## 4 Experimental Results and Analysis
### Evaluation of Robustness
#### 4.2.2 RST Attacks  
In Figures 16-18, watermarked images and extracted watermarks of the proposed scheme are shown under RST attacks with different parameters. For rotation, there are five cases of parameters simulated in the scheme, which contain \(2^{\circ}\), \(5^{\circ}\), \(10^{\circ}\), \(30^{\circ}\), and \(45^{\circ}\). In the scaling attacks, four different scales are performed to change the size of watermarked images, i.e., 0.25, 0.5, 0.9, and 1.2. In the perspective of translation attacks, the translation of watermarked image is performed in horizontal and vertical directions for 128 pixels, respectively.  
(1) Rotation.  
Figure 16: _Cont._  
Figure 15: Watermarked images and extracted watermarks under median filter (3 \(\times\) 3): (**a**) watermarked Lena; (**b**) extracted watermark \(w_{1}\); (**c**) watermarked Barbara; (**d**) extracted watermark \(w_{2}\).  
Figure 16: Watermarked images and extracted watermarks under rotation: (**a**) rotated Lena (\(2^{\circ}\)); (**b**) extracted watermark \(w_{1}\); (**c**) rotated Barbara (\(2^{\circ}\)); (**d**) extracted watermark \(w_{2}\); (**e**) rotated Lena (\(5^{\circ}\)); (**f**) extracted watermark \(w_{1}\); (**g**) rotated Barbara (\(5^{\circ}\)); (**h**) extracted watermark \(w_{2}\); (**i**) rotated Lena (\(10^{\circ}\)); (**j**) extracted watermark \(w_{1}\); (**k**) rotated Barbara (\(10^{\circ}\)); (**l**) extracted watermark \(w_{2}\); (**m**) rotated Lena (\(30^{\circ}\)); (**n**) extracted watermark \(w_{1}\); (**o**) rotated [PERSON] (\(30^{\circ}\)); (**p**) extracted watermark \(w_{2}\); (**q**) rotated [PERSON] (\(45^{\circ}\)); (**r**) extracted watermark \(w_{1}\); (**s**) rotated [PERSON] (\(45^{\circ}\)); (**t**) extracted watermark \(w_{2}\).  
(3) Translation.  
Table 2 gives the robustness performance of the proposed scheme on two sets of host images and watermarks. [PERSON] image and character watermark are given in the first column, and [PERSON] image and logo watermark are given in the second column. The PSNR value of the proposed method is 54.6 dB, which expresses good imperceptibility of the watermarked image.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Different Attacks** & **[PERSON] and \(w_{1}\)** & **[PERSON] and \(w_{2}\)** \\ \hline Scaling (0.25) & 0.9744 & 0.9713 \\ Scaling (0.5) & 0.9919 & 0.9910 \\ Scaling (0.9) & 0.9931 & 0.9731 \\ Scaling (1.2) & 0.9906 & 0.9726 \\ Rotation (2\({}^{\circ}\)) & 0.9741 & 0.9703 \\ Rotation (5\({}^{\circ}\)) & 0.9813 & 0.9659 \\ Rotation (10\({}^{\circ}\)) & 0.9861 & 0.9738 \\ Rotation (30\({}^{\circ}\)) & 0.9861 & 0.9822 \\ Rotation (45\({}^{\circ}\)) & 0.9828 & 0.9839 \\ Horizontal cycling translation (128 pixels) & 0.9964 & 0.9962 \\ Vertical cycling translation (128 pixels) & 0.9964 & 0.9962 \\ JPEG (100) & 0.9966 & 0.9964 \\ Median filter (3 \(\times\) 3) & 0.9913 & 0.9848 \\ Center cropping (25\%) & 0.9179 & 0.8859 \\ Gaussian noise (0, 0.01) & 0.9788 & 0.9799 \\ Gaussian noise (0, 0.05) & 0.9509 & 0.9206 \\ Salt and pepper noise (0.01) & 0.9758 & 0.9759 \\ Salt and pepper noise (0.05) & 0.9644 & 0.9476 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Robustness performance of the proposed scheme.  
Figure 18: Watermarked images and extracted watermarks under translation attacks: (**a**) horizontally translated Lena (128 pixels); (**b**) extracted watermark \(w_{1}\); (**c**) horizontally translated Barbara (128 pixels); (**d**) extracted watermark \(w_{2}\); (**e**) vertically translated Lena (128 pixels); (**f**) extracted watermark \(w_{1}\); (**g**) vertically translated Barbara (128 pixels); (**h**) extracted watermark \(w_{2}\).  
To illustrate the robustness of the proposed algorithm against multiple attacks, Table 3 is given for robustness performance, which suggests that the proposed scheme has a good ability for multiple attacks' resistance.