MINERAL IDENTIFICATION WITH HYPERSPECTRAL IMAGERY NEAR THE ATMOSPHERIC WATER ABSORPTION BAND

The Toolbox for Research and Exploration (TREX) team conducted a two-week field campaign simulating exploration of a planetary surface to test autonomous geologic mapping techniques. Carnegie Mellon’s semi-autonomous rover, Zoë, and a suite of instruments collected in situ measurements and visible near infrared (VNIR) spectra and used Tetracorder, an open source mineral identification program, to update maps for the remote science team. The field site Yellow Cat, Utah, was selected for its lack of vegetation, diverse geologic units, distinct layering, and data from previous mapping efforts. Geologic units at the site are exposed in the surrounding cliffs but are otherwise inaccessible for in situ measurements. To include this valuable geologic context, a tripod-mounted PikaIR hyperspectral imager from Resonon was deployed to map the cliffs at high resolution >0.1m/pixel and in the near infrared from 0.9-1.7µm. Typically, absorption by water vapor in Earth’s atmosphere makes several spectral bands around 1.4 μm inaccessible for remote sensing. Previous studies using Tetracorder began identifying minerals with features in this region but did not have enough data to determine if the shape of the absorption feature was unique enough to each mineral. During this study, the amount of atmosphere between the imager and target was on the order of 40-60 meters, much less than experienced from an aircraft or spacecraft, and preliminary review of the spectra showed some enhanced signal integrity. This study focuses on features in the 1.3-1.5 μm range and compares them to the broader USGS library of minerals to determine if there is enough data for a unique mineral identification and compares these results with other data collected by the TREX team. This study not only tests the limits of current spectral analysis software in identifying minerals within regions of challenging absorption bands but also explores the potential of high-resolution hyperspectral imaging in enhancing the accuracy of geological surveys on planetary surfaces. While these data were taken from a tripod, this imager could also be mounted to a drone or the rover for future planetary surface or TREX exploration.