Table 2 Spectral indices and texture from NDVI computed from the images captured by the Parrot Sequoia multispectral sensor at crown level

 Normalized difference vegetation index

NDVI

NDVI = (B4 – B2) / (B4 + B2)

(Rouse Jr et al. 1974)

 Green NDVI

GNDVI

GNDVI = (B4 – B1) / (B4 + B1)

(Gitelson et al. 1996)

 Red edge normalised difference Vegetation index

RENDVI

RENDVI = (B4 – B3) / (B4 + B3)

(Gitelson and Merzlyak 1994)

 Green RENVI

REGNDVI

REGNDVI = (B3 – B1) / (B3 + B1)

(Buschmann and Nagel 1993)

 Red RENVI

RERNDVI

REGNDVI = (B3 – B2) / (B3 + B2)

(Barnes et al. 2000)

 Normalized green-red vegetation index

NGRVI

NGRVI = (B1 – B2) / (B1 + B2)

(Motohka et al. 2010)

 Non-linear index

NLI

NLI = (B4^2 – B2) / (B4^2 + B2)

(Goel and Qin 1994)

 Optimized soil adjusted vegetation index

OSAVI

SAVI = ((B4 – B2) / ((B4 + B2) + 0.15)) × (1 + 0.5)

(Huete 1988)

Texture

ndvi_GLCM

(window size of 3 × 3 pixels and a 45 degree shift)

“mean”, “variance”, “homogeneity”, “contrast”, “dissimilarity”, “entropy”, “second_moment”, “correlation”