Iterative Pixel Purity Index

Pixel Purity Index (PPI) has been widely used in endmember extraction. While it is available in ENVI software there are several interesting issues arising in its implementation. This paper re-invents the wheel by re-visiting the design rationale of the PPI and re-designing algorithms to implement PPI in an iterative manner, referred to as iterative PPI (IPPI) which iterates the PPI in two processes, one for data sample vectors and the other for skewers, each of which can be implemented as a real time processing algorithm in a causal manner. The proposed IPPI can be implemented automatically and resolves the main issue of requiring human intervention to determine parameters.