We analyze 7258 global spectral irradiance functions over 0.4–2.2 μm that were acquired over a wide range of conditions at Boulder, Colorado, during the summer of 1997. We show that low-dimensional linear models can be used to capture the variability in these spectra over both the visible and the 0.4–2.2 μm spectral ranges. Using a linear model, we compare the Boulder data with the previous study of Judd <i>et al.</i> [J. Opt. Soc. Am. <b>54</b>, 1031 (1964)] over the visible wavelengths. We also examine the agreement of the Boulder data with a spectral database generated by using the MODTRAN 4.0 radiative transfer code. We use a database of 223 minerals to consider the effect of the spectral variability in the global spectral irradiance functions on hyperspectral material identification. We show that the 223 minerals can be discriminated accurately over the variability in the Boulder data with subspace projection techniques.
© 2003 Optical Society of America
Zhihong Pan, Glenn Healey, and David Slater, "Global spectral irradiance variability and material discrimination at Boulder, Colorado," J. Opt. Soc. Am. A 20, 513-521 (2003)