## 3 Experiments
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multicolumn{11}{c}{**(A) Results by Using the GF-3 Data**} \\ \hline \multicolumn{11}{c}{**The H/alpha Method**} \\ \hline \% & \(\underline{z9}\) & \(\underline{z6}\) & \(\underline{z5}\) & \(\underline{z2}\) & \(\underline{z1}\) & \(\underline{z8}\) & \(\underline{z7}\) & \(\underline{z4}\) & **CA** & **Overall Accuracy** \\ \hline Ocean & 100 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 100 & \\ Forest & 1.00 & 46.33 & 40.86 & 8.90 & 0.11 & 0.03 & 0.26 & 2.51 & 49.76 & \\ Urban & 12.32 & 27.93 & 38.20 & 0.04 & 0 & 5.07 & 4.96 & 11.48 & 16.44 & \\ Tilted Urban & 2.35 & 17.23 & 44.30 & 8.89 & 1.40 & 0.35 & 1.45 & 24.03 & 25.48 & \\ \hline \multicolumn{11}{c}{**The \(\Delta\alpha_{\text{B}}/\alpha_{\text{B}}\) Method**} \\ \hline \% & \(\underline{z9}\) & \(\underline{z6}\) & \(\underline{z5}\) & \(\underline{z2}\) & \(\underline{z1}\) & \(\underline{z8}\) & \(\underline{z7}\) & \(\underline{z4}\) & **CA** & **Overall Accuracy** \\ \hline Ocean & 100 & 0 & 0 & 0 & 0 & 0 & 0 & 100 & \\ Forest & 1.74 & 44.50 & 35.81 & 12.54 & 1.09 & 0.54 & 2.21 & 1.58 & 48.35 & \\ Urban & 8.06 & 30.85 & 22.54 & 0.95 & 0.02 & 13.03 & 5.71 & 18.84 & 24.55 & \\ Tilted Urban & 2.96 & 16.78 & 32.10 & 11.29 & 2.77 & 2.39 & 17.32 & 14.40 & 31.72 & \\ \hline \multicolumn{11}{c}{**(B) Results by Using the Radarsat-2 Data**} \\ \hline \multicolumn{11}{c}{**The H/alpha Method**} \\ \hline \% & \(\underline{z9}\) & \(\underline{z6}\) & \(\underline{z5}\) & \(\underline{z2}\) & \(\underline{z1}\) & \(\underline{z8}\) & \(\underline{z7}\) & \(\underline{z4}\) & **CA** & **Overall Accuracy** \\ \hline Ocean & 99.87 & 0.13 & 0 & 0 & 0 & 0 & 0 & 0 & 99.87 & \\ Forest & 0.17 & 29.28 & 49.95 & 14.94 & 0.35 & 0.08 & 0.30 & 4.93 & 64.89 & \\ Urban & 1.62 & 10.67 & 35.65 & 0.22 & 0.04 & 1.03 & 14.30 & 36.45 & 50.76 & \\ Tilted Urban & 0.83 & 4.81 & 26.70 & 16.54 & 7.18 & 0.23 & 3.19 & 40.51 & 43.71 & \\ \hline \multicolumn{11}{c}{**The \(\Delta\alpha_{\text{B}}/\alpha_{\text{B}}\) Method**} \\ \hline \% & \(\underline{z9}\) & \(\underline{z6}\) & \(\underline{z5}\) & \(\underline{z2}\) & \(\underline{z1}\) & \(\underline{z8}\) & \(\underline{z7}\) & \(\underline{z4}\) & **CA** & **Overall Accuracy** \\ \hline Ocean & 99.93 & 0.07 & 0 & 0 & 0 & 0 & 0 & 0 & 99.93 & \\ Forest & 0.31 & 28.40 & 42.38 & 19.20 & 1.93 & 0.67 & 3.88 & 3.24 & 61.59 & \\ Urban & 2.04 & 10.15 & 14.92 & 1.59 & 0.07 & 9.74 & 18.90 & 42.59 & 61.49 & \\ Tilted Urban & 1.06 & 4.66 & 18.45 & 11.62 & 5.83 & 1.32 & 32.49 & 24.59 & 57.07 & \\ \hline \end{tabular}
\end{table} 
Table 1: Classification accuracies (in percentage) of the \(H/alpha\) method and the \(\Delta\alpha_{\text{B}}/\alpha_{\text{B}}\) method for four typical regions. The four areas were outlined in Figure 2. \(z1-z9\) are the segmentation zones in both the \(H/alpha\) and \(\Delta\alpha_{\text{B}}/\alpha_{\text{B}}\) planes [13]. Figure 4: Scatter plots by using (**a**) the GF-3 data and (**b**) the Radarsat-2 data. Blue dots indicate samples from ocean surface, cyan samples from the forest area, magenta samples from the urban area, and red samples from the tilted urban area. similar. On the aspect of \(alpha\) images, the Radarsat-2 data shows a larger center difference between the forest area and the urban area in comparison with the GF-3 data, but both data sets have similar standard deviations in \(alpha\). On the aspect of \(\Delta\alpha_{\rm B}\) and \(\alpha_{\rm B}\). parameters, the GF-3 data gives smaller standard deviations for the four themes than the Radarsat-2 data. However, it also bears a smaller distance between the forest and the urban theme centers. For the ocean area, the GF-3 data shows that the ocean theme is far away from the other theme centers with small standard deviations in all the four polarimetric parameters, further indicating that GF-3 data has a great potential for monitoring targets on the ocean surface. The above analysis only considers the physical scattering mechanism of each terrain type.