Table 1 The optimal wavelength combination of different spectral indices characterizing image grayscale and spectral reflectance
Types | Optimal correction factor | Wavelength 1 | Wavelength 2 | Wavelength 3 | Correlation coefficient |
|---|---|---|---|---|---|
NDSI | – | 995 | 645 | – | 0.845 |
DSI | – | 995 | 660 | – | 0.761 |
RSI | – | 995 | 645 | – | 0.742 |
TNDI | α = − 1, β = − 1.5 | 745 | 750 | 670 | 0.966 |
TDI | α = 1.5 | 565 | 655 | 635 | 0.878 |
TRI | α = positive number | 535 | 710 | 655 | 0.905 |