Value Range: -1–  1

The greenness index, also referred to as Green Leaf Index, represents the relation between the reflectance in the green channel compared to the other two visible light channels (red and blue).

It is computed as (2*G-R-B)/(R+G+B). The higher the green reflection compared to the other channels the lower the greenness index. A value of -1 would represent a full reflection in the green channel and no reflection in the other two channels. 

The illustration below shows three different examples for the calculation of greenness. The X axis represents a simplified spectrum in the range from 400 to 1,000nm. The Y axis shows the relative reflectance for each wavelength. The colored blocks represent the measurement channels of PlantEye with standard configuration.