2.2.2. Published Vegetation Indices

The accuracy of LCC retrieval using the MDATT and DLARI indices was compared with that of 12 published vegetation indices that were originally proposed for chlorophyll content retrieval and have proven to be highly correlated with LCC [34]. The types of indices included single-band index (e.g., 1/R700), two-band indices (e.g., VOG1 = R740/R720), three-band indices (e.g., DATT = (R850 − R710)/(R850 − R680)), as well as four-band indices (e.g., VOG2 = (R734 − R747)/(R715 + R720)). The formulae of the indices are provided in Table 1. In addition, two MDATTs proposed by Lu et al. [21] were used to evaluate the optimal wavelengths in the MDATT for peanut LCC estimation. The first MDATT in Table 1 with wavelengths at 691 nm, 745 nm, and 736 nm was developed from the adaxial surface reflectance of woody plants, whilst the second MDATT with wavelengths at 721 nm, 744 nm, and 714 nm was based on a mixture of reflectance for both adaxial and abaxial surfaces.


