Vegetation Indices
Different bands of a multispectral image may be combined to accentuate the vegetated areas.
One such combination is the ratio of the near-infrared band to the red band. This ratio is known
as the Ratio Vegetation Index (RVI)
RVI = NIR/Red
Since vegetation has high NIR reflectance but low red reflectance, vegetated areas will have
higher RVI values compared to non-vegetated aeras. Another commonly used vegetation index is
the Normalised Difference Vegetation Index (NDVI) computed by
NDVI = (NIR - Red)/(NIR + Red)