Table 5.
Effect of data reduction for different signal-to-noise ratios (SNR) on coefficients of determination obtained for the Ca mass fraction for the three multivariate methods PLSR, Lasso and GPR, application to 137 spectra (samples).
| Method | Raw | Background Corrected | SNR 1 | SNR 3 | SNR 5 | SNR 10 | SNR 22 |
|---|---|---|---|---|---|---|---|
| File size/kB | 17,745 | 7601 | 254 | 137 | 95 | 61 | 35 |
| Data points/spectrum | 7701 | 7701 | 238 | 179 | 149 | 115 | 81 |
| R² (PLSR) | 0.82 | 0.80 | 0.73 | 0.76 | 0.76 | 0.76 | 0.70 |
| R² (Lasso) | 0.84 | 0.80 | 0.79 | 0.80 | 0.82 | 0.74 | 0.64 |
| R² (GPR) | 0.86 | 0.85 | 0.79 | 0.73 | 0.75 | 0.83 | 0.76 |