Hyperspectral imagery for mineral exploration: comparison of data from two airborne sensors

摘要

Abstract: Hyperspectral image data sets acquired near Cuprite, Nevada in 1995 with the SWIR full spectrum imager (SFSI) and in 1996 with the Airborne Visible/IR Imaging Spectrometer (AVIRIS) are analyzed with a spectral unmixing procedure and the result compared. The SFSI image has pixels on 1 m by 1.5 m centers, the AVIRIS on 17 m centers; the region imaged by SFSI is a small portion of the full AVIRIS scene. Both have nominal spectral band center spacings of about 10 nm. The image data, converted to radiance units, are atmospherically corrected and converted to surface reflectance. Spectral end members are extracted automatically from the two data sets; those representing mineral species common to both are compared to each other and to reference spectra obtained with a portable IR mineral analyzer. The full sets of end members are used in a constrained linear unmixing of the respective hyperspectral image cubes. The resulting unmixing fraction images derived from the AVIRIS and the SFSI data sets for the minerals alunite, buddingtonite, and kaolinite exhibit strong similarities. !12