PRINCIPAL COMPONENT ANALYSIS FOR ALTERATION MAPPING 论文

摘要

Reducing the number of image bands input for principal component analysis (PCA) ensures that certain materials will not be mapped and increases the likelihood that others will be unequivocally mapped into only one of the principal component images. In arid terrain, PCA of four TM bands will avoid iron-oxide and thus more reliably detect hydroxyl-bearing minerals if only one input band is from the visible spectrum. PCA for iron-oxide mapping will avoid hydroxyls if only one of the SWIR bands is used. A simple principal component color composite image can then be created in which anomalous concentrations of hydroxyl, hydroxyl plus iron-oxide, and iron-oxide are displayed brightly in red-green-blue (RGB) color space. This composite allows qualitative inferences on alteration type and intensity to be made which can be widely applied.