The VARI operator algorithm computes the Visible Atmospherically Resistant Index from a given product.

The VARI results from the following equation:

VARI = (G - R) / (G + R - B)

, where:

The bands are:

- B is the Blue band
- G is the Green band
- R is the Red band

Also the processor computes an additional flags band called 'vari_flags' with the following bit coding:

Bit Position	Description
Bit 0	The computed value for VARI is NAN or is Infinite
Bit 1	The computed value for VARI is less than -1 (minus one)
Bit 2	The computed value for VARI is greater than 1 (one)