Normalized Difference Vegetation Index (NDVI): Normalized Difference Vegetation Index proposedby Rouse et.al. (1973), NDVI is a measure of healthy, green vegetation. Thecombination of its normalized difference formulation and use of the highestabsorption and reflectance regions of chlorophyll make it robust over a widerange of conditions, the value of this index ranges from -1 to 1. The commonrange for green vegetation is 0.
2 to 0.8 8, (1) Where is reflectance AtmosphericallyResistant Vegetation Index (ARVI): Main advantages of this index is its resistanceto atmospheric effects, as compared to the Normalized Difference VegetationIndex which is accomplished by a self-adjustment procedure for the atmosphericinfluence on the red band, using the difference in the radiance between theblue and the red bands to correct the radiance in the red band. Simulationsusing radiative transfer computations on arithmetic and natural surfacespectra, for numerous atmospheric conditions, show that ARVI has an analogousdynamic range to the NDVI, but it is less sensitive to atmospheric effects thanthe NDVI 9.
The formula for ARVI for narrowband data is as given below. ARVI: (?864 ? 2 × ?671 ? ?467)/(?864 + 2 × ?671 ? ?467) (2) RedEdge Normalized Difference Vegetation Index (RENDVI): Red Edge Normalized Difference Vegetation Index: The reflectance near700 nm has found to be very sensitive to red edge position as well aschlorophyll concentration 10 RENDVI gives normalized value at the wavelengthof 752 nm and 701nm the equation for this Index is as given in equation (3). RENDVI= (p752 ? p701)/(p752 + p701) (3) ModifiedRed Edge Normalized Difference Vegetation Index (MRENDVI): Thisindex is a modification of the RedEdge NDVI thatcorrects for leaf specular reflection.
It capitalizes on the sensitivity of thevegetation red edge to small changes in canopy foliage content, gap fraction,and senescence. Applications include precision agriculture, forest monitoring,and vegetation stress detection.The value of this index ranges from -1 to1. The common range for green vegetation is 0.2 to 0.7.
See NarrowbandDefinitions for theallowable range of wavelengths 11, 12.. (4) NormalizedDifference Infrared Index (NDII):NDII is thereflectance estimation that represents to changes in water substance of plantcanopy. It is not the simple ratio index it is normalized difference index. Itincreases with increasing water contents in the canopy its range is -1 to 1,forgreen vegetation it varies from 0.
02 to 0.6 13, 14. It is defined as follows: