Table 2.

Common Vegetation indices used for plant disease detection

Index	Name	Formula based on reflectance of given bands or wavelengths (nm)	Reference
DVI	difference vegetation index	NIR - R	Tucker and Red (1979)
RVI	ratio vegetation index	NIR / R	Jordan (1969)
NDVI	normalized differential vegetation index	(NIR-R) / (NIR + R)	Rouse et al. (1974)
GNDVI	Green normalized difference vegetation index	index (NIR - G) / (NIR + G)	Gitelson et al. (1996)
NBNDVI	Narrow-band normalized difference vegetation index	(850–680) / (850 + 680)	Thenkabail et al. (2000)
NRI	Nitrogen reflectance index	(570—670) / (570 + 670)	Filella et al. (1995)
TVI	Triangular vegetation index	0.5[120(750–550) - 200(670–550)]	Broge and Leblanc (2001)
P/PRI	Photochemical/Physiological Reflectance Index	(531–570) / (531 + 570)	Gamon et al. (1992)
TCARI	The transformed chlorophyll absorption and reflectance index	3[(700–670) - 0.2(700–550)(700 / 670)]	Haboudane et al. (2004)
MCARI	Modified chlorophyll absorption ratio index	[(701–671)- 0.2(701–549)] / (701/671)	Daughtry et al. (2000)
RVSI	Red-Edge Vegetation Stress Index	[(712+752)/2] - 732	Merton and Huntington (1999)
PSRI	Plant Senescence Reflectance Index	(680–500)/750	Merzlyak et al. (1999)
ARI	Anthocyanin Reflectance Index	(550)-1 - (700)-1	Gitelson et al. (2001)
λred	Red edge position	Wavelength at red edge	Gong et al. (2002)
drred	Red edge slope	Maximum value of 1st derivative with in red edge	Gong et al. (2002)
Σdr680–760 nm	The area of the red edge peak	The area under the derivative curve in the region of red edge	Gong et al. (2002)

R = Reflectance of red band within wavelengths 650 to 680 nm

NIR = Reflectance of near-infrared band within wavelengths 780 to 890 nm

G = Reflectance of green band within wavelengths 560 to 600 nm.