View source for NDPI (Lacaux et al., 2006)

Normalized Difference Pond Index (NDPI) :
NDPI = (MIR-G)/(MIR+G)

Reference: J-P. Lacaux, Y. M. Tourre, C. Vignolle, J-A. Ndione, and M. Lafaye, "Classification of Ponds from High-Spatial Resolution Remote Sensing: Application to Rift Valley Fever Epidemics in Senegal," Remote Sensing of Environment 106 66–74, Elsevier Publishers: 2007

Replace the NDVI used with false channels.