From: FPGA Implementation of the Pixel Purity Index Algorithm for Remotely Sensed Hyperspectral Image Analysis
USGS
ENVI
PPI
Our FPGA-based
mineral
software
approximation
Alunite
0.084
Buddingtonite
0.071
0.068
Calcite
0.089
Kaolinite
0.136
0.132
Muscovite
0.092
0.081