Figure 1.
Hyperspectral imaging.
Figure 2.
Schematic diagram of the hyperspectral imaging system.
Figure 3.
Main steps of this study.
Table 1.
Reference values of color (ΔL*, Δa* and Δb*) of tea leaves in calibration and prediction sets.
Table 2.
Performance of models in calibration and prediction for predicting color (ΔL*, Δa* and Δb*) using different preprocessing methods.
Table 3.
Effective wavelengths recommended by CARS and SPA, respectively.
Figure 4.
Measured vs. predicted values of calibration and prediction by CARS-LS-SVM and SPA-LS-SVM models, respectively.
(a): CARS-LS-SVM-ΔL*; (b): CARS-LS-SVM-Δa*; (c): CARS-LS-SVM-Δb*; (d): SPA-LS-SVM-ΔL*; e): SPA-LS-SVM-Δa*; (f): SPA-LS-SVM-Δb*.
Table 4.
Performance of different models in calibration and prediction for predicting color (ΔL*, Δa* and Δb*).
Table 5.
Correct classification rates based on LS-SVM.