Table 6.
Determination accuracies of Ni concentrations based on spectral bands associated with SOM.
| Preprocessing | PLSR | PCR | SVMR | |||
|---|---|---|---|---|---|---|
| RMSE | R2 | RMSE | R2 | RMSE | R2 | |
| SG + CR | 1.41 | 0.61 | 1.56 | 0.52 | 2.09 | 0.14 |
| SG + CR + NOR | 2.19 | 0.05 | 2.2 | 0.04 | 2.11 | 0.13 |
| SG + CR + MSC | 1.41 | 0.61 | 2.51 | 0.12 | 2.09 | 0.14 |
| SG + CR + SNV | 1.41 | 0.61 | 2.05 | 0.17 | 2.09 | 0.14 |
| SG + CR + FD | 0.36 | 0.98 | 1.74 | 0.4 | 1.78 | 0.43 |
| SG + CR + NOR + FD | 2.12 | 0.11 | 1.98 | 0.22 | 2.04 | 0.02 |
| SG + CR + MSC + FD | 0.3 | 0.98 | 1.59 | 0.5 | 1.57 | 0.53 |
| SG + CR + SNV + FD | 1.87 | 0.31 | 1.62 | 0.48 | 1.53 | 0.57 |
| SG + CR + SD | 1.7 | 0.43 | 1.88 | 0.3 | 1.23 | 0.78 |
| SG + CR + NOR + SD | 2.04 | 0.18 | 2.11 | 0.12 | 2 | 0.25 |
| SG + CR + MSC + SD | 1.63 | 0.48 | 1.79 | 0.37 | 1.13 | 0.82 |
| SG + CR + SNV + SD | 1.68 | 0.44 | 1.7 | 0.43 | 1.22 | 0.78 |
| SG + CR + LOG | 1.28 | 0.68 | 1.57 | 0.51 | 2.08 | 0.14 |
| SG + CR + NOR + LOG | 3.39 | 0.15 | 2.2 | 0.04 | 3.13 | 0.35 |
| SG + CR + MSC + LOG | 1.4 | 0.61 | 2.05 | 0.17 | 2.08 | 0.15 |
| SG + CR + SNV + LOG | 2.21 | 0.03 | 2.23 | 0.01 | 2.11 | 0.12 |