A photometric function for analysis of lunar images in the visual and infrared based on Moon Mineralogy Mapper observations

Abstract

Changes in observed photometric intensity on a planetary surface are caused by variations in local viewing geometry defined by the radiance incidence, emission, and solar phase angle coupled with a wavelength-dependent surface phase function f(α, λ) which is specific for a given terrain. In this paper we provide preliminary empirical models, based on data acquired inflight, which enable the correction of Moon Mineralogy Mapper (M3) spectral images to a standard geometry with the effects of viewing geometry removed. Over the solar phase angle range for which the M3 data were acquired our models are accurate to a few percent, particularly where thermal emission is not significant. Our models are expected to improve as additional refinements to the calibrations occur, including improvements to the flatfield calibration; improved scattered and stray light corrections; improved thermal model corrections; and the computation of more accurate local incident and emission angles based on surface topography. Copyright 2011 by the American Geophysical Union.