Figure 3

Principal component analysis (PCA) of the four classes were performed with MATLAB R2018b to analyze the class-variance. To show the clusters of the classes, we used only 1000 spectral data of each class. The data were randomly selected.

Principal component analysis (PCA) of the four classes were performed with MATLAB R2018b to analyze the class-variance. To show the clusters of the classes, we used only 1000 spectral data of each class. The data were randomly selected.