Remote determination of small-scale three-dimensional surface properties based on imaging photometry and polarimetry: an introduction

摘要

The remote sensing analysis of planetary surfaces is a field in which photopolarimetric techniques allow the estimation of the average small-scale 3D properties of the examined surfaces (i.e. on millimeter or sub-millimeter scales) from large distances. This work provides an overview of image-based photometric and polarimetric methods for the remote determination of small-scale 3D properties of planetary regolith surfaces. Specifically, the surface porosity governs the phase angle dependence of the reflectance function of the surface material for near-zero phase angles, while the reflectance behavior at large phase angles between around 90° and 180° allows to estimate the surface roughness on sub-millimeter and millimeter scales. For the lunar regolith, a calibration of the phase angle dependence of the polarization behavior of the light reflected from the surface based on returned lunar sample material provides a framework to determine the median regolith grain size based on measurements of the polarization degree. In this work, the corresponding methodologies as well as their application to specific planetary bodies are discussed. Where deemed favorable, new photometric and polarimetric measurements of prototypical areas of the lunar surface are provided to exemplify the described approaches in an illustrative manner.