# Table 6 Summary of vegetation indices derived from the aerial orthophotos for the estimation of aboveground biomass in wheat

Index Name Formulation References
VARI Visible Atmospherically Resistant Index $${\text{VARI}} = \frac{g - r}{g + r - b}$$ Gitelson et al. 
ExG Excess Green Index ExG = 2 * g − r − b Woebbecke et al. 
ExR Excess Red Vegetation Index $${\text{ExR}} = \frac{1.4R - G}{G + R + B}$$ Meyer et al. 
ExB Excess Blue Vegetation Index $${\text{ExB}} = \frac{1.4*B - G}{G + R + B}$$ Mao et al. 
ExGR Excess Green minus Excess Red ExGR = ExG–ExR Neto et al. 
GRVI Green Red Vegetation Index $${\text{GRVI}} = \frac{G - R}{G + R}$$ Tucker et al. 
MGRVI Modified Green Red Vegetation Index $${\text{MGRVI}} = \frac{{G^{2} - R^{2} }}{{G^{2} + R^{2} }}$$ Bendig et al. 
GLI Green Leaf Index $${\text{GLI}} = \frac{2*g - r - b}{ - r - b}$$ Louhaichi et al. 
RGBVI Red Green Blue Vegetation Index $${\text{RGBVI}} = \frac{{G^{2} - B*R}}{{G^{2} + B*R}}$$ Bendig et al. 
IKAW Kawashima Index $${\text{IKAW}} = \frac{R - B}{R + B}$$ Kawashima et al. 
1. R, G and B represent the digital number of red, green and blue channels, respectively. r = R/(R + G + B), g = G/(R + G + B), b = B/(R + G + B) 