Table 4.
Evaluation of LWC prediction models fitted by SVR
| Spectrally-derived data | Feature band screening methods | Calibration (n = 454) | Validation (n = 120) | ||
|---|---|---|---|---|---|
| R2 | RMSE | R2 | RMSE | ||
| R | None | 0.9705 | 0.0246 | 0.9352 | 0.0554 |
| CARS | 0.9616 | 0.028 | 0.9078 | 0.0661 | |
| LASSO | 0.9529 | 0.0311 | 0.8841 | 0.0741 | |
| UVE | 0.9679 | 0.0256 | 0.9248 | 0.0597 | |
| RLR | None | 0.9793 | 0.0206 | 0.964 | 0.0413 |
| CARS | 0.9845 | 0.0178 | 0.9606 | 0.0432 | |
| LASSO | 0.9757 | 0.0223 | 0.9387 | 0.0539 | |
| UVE | 0.9851 | 0.0175 | 0.9468 | 0.0502 | |
| FDRL | None | −20.0427 | 0.6568 | −15.684 | 0.8887 |
| CARS | −2.0746 | 0.251 | −0.3743 | 0.2551 | |
| LASSO | −19.246 | 0.6442 | −38.9445 | 1.3751 | |
| UVE | −8.8804 | 0.45 | −10.3724 | 0.7337 | |
| SDRL | None | −3,401,226.87 | 264.0478 | −3,400,301 | 401.2004 |
| CARS | −875,789.720 | 133.9877 | −849,911.9 | 200.581 | |
| LASSO | −4,670,267.21 | 309.4109 | −2,675,497 | 355.8812 | |
| UVE | −603,805.878 | 111.2535 | −933,232.4 | 210.1831 | |
The model with the highest R2 value for the calibration dataset was shown in bold
R raw reflectance, RLR the reciprocal logarithm of reflectance, FDRL first-order differential of the reciprocal logarithm of reflectance, SDRL second-order differential of the reciprocal logarithm of reflectance, CARS competitive adaptive reweighted sampling, LASSO least absolute shrinkage and selection operator, UVE uninformative variable elimination