Figure 7.

In this figure, the features were selected by the mutual information. The abscissa was the index of selected features at each cycle. There was one-to-one correspondence between the index and the Table 1. For example, the 5th feature was selected at the second cycle in network1. It indicated that the 5th feature (${\gamma }_2$) had the greatest mutual information in all of the features except the 8th feature ($N_{obj1}$). Its ordinate was the sum mutual information of $N_{obj1}$ and ${\gamma }_2$. In network1, 11 features were used, and the $H\left(C\right)=1.5488$. In addition, in network2, 19 features were used, and $H\left(C\right)=2.3219$.