The NDYI operator algorithm computes the Normalized Difference Yellowness Index from a given product.

The NDYI results from the following equation:

NDYI = (G - B) / (G + B)

, where:

The bands are:

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

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

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