Fig. 1. NIR spectra of tobacco leaves (a) and medicine capsules (b)
Blue: Calibration set; Red: Prediction set

Fig. 2. Derivative spectra of tobacoo leaves (a) and medicine capsules (b)
Blue: Calibration set; Red: Prediction set

Fig. 3. Clustering in principal component space (the distribution in PC1 and PC2 space)
(a): Tobacco leaves; (b): Medicine capsules

Fig. 4. Descrimination filters for the tobacoo leaves (a) and the medicine capsules (b)

Fig. 5. Projection in the two-dimensional space of the filters
(a): Tobacoo leaves; (b): Medicine capsules; The insets circled by the dot-line show the enlarged graphs. The calibration and prediction samples are plotted by blind and solid points, respectively