The REDSI operator algorithm computes the Red-Edge Disease Stress Index from a given product.

The REDSI results from the following equation:

REDSI = ((705.0 - 665.0) * (RE3 - R) - (783.0 - 665.0) * (RE1 - R)) / (2.0 * R)

, where:

The bands are:

- RE1 is the Red Edge 1 band
- RE3 is the Red Edge 3 band
- R is the Red band

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

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