Paper: Imaging Spectroscopy: Earth and Planetary Remote Sensing with the PSI Tetracorder and Expert Systems from Rovers to EMIT and Beyond
Authors: Roger N. Clark, Gregg A. Swayze, K. Eric Livo, Philip G. Brodrick, Eldar Noe Dobrea, Srinivasan Vijayarangan, Robert O. Green, David Wettergreen, Alberto Candela, Amanda Hendrix, Carlos Pérez García-Pando, Neil C. Pearson, Melissa D. Lane, Adolfo González-Romero, Xavier Querol
Figure caption: (a) Group 1 minerals mapped (left image). This Tetracorder group 1 map is Fe2+ and Fe3+ electronic transitions in ferric and ferrous-bearing minerals. The image on the right is an approximate true color image using red, green, and blue channels from the spectrometer data. It is approximate because only a single channel for each color is used instead of a spectral profile of human eye response. The user can define the channels used for each sensor to make the color image on the right. The channels used for these 1995 AVIRIS data are 30, 20, and 10 for red, green, and blue, respectively. This is a Tetracorder 5.27 standard product with expert system 5.27e1. All code and spectral libraries are in the Zenodo repository (R. N. Clark 2024) and on GitHub to reproduce this image and others in Figures 11(b)–(g). (b). Group 2 minerals mapped (left image) and approximate true color (right image). Tetracorder Group 2 minerals in this map are due to vibrational absorptions, with diagnostic absorption mainly in the 2–2.5 μm region. This is a Tetracorder standard product with expert system 5.27e1. (c). EMIT 8, custom RGB color-composite product (left image) and approximate true color (right image). These are Tetracorder Group 2 minerals in this map and are due to vibrational absorptions with diagnostic absorption mainly in the 2–2.5 μm region. This is a Tetracorder standard product with expert system 5.27e1. (d). Muscovite aluminum content in the muscovite octahedral sites illustrates a specialty product useful for specific applications (left image) and approximate true color (right image). These are Tetracorder Group 2 minerals in this map and are due to vibrational absorptions with diagnostic absorption in the 2–2.5 μm region. Constructing additional products like this is copying and modifying a simple script to put in the materials desired and their colors. This is a Tetracorder standard product with expert system 5.27e1. (e). Detected vegetation spectral type (left image) and approximate true color (right image). The spectral type is a Tetracorder Case 2 analysis after vegetation was detected in Group 3. This is a Tetracorder standard product with expert system 5.27e1. (f). Vegetation water content (left image) and approximate true color (right image). The water image on the left is an RGB color composite derived from Tetracorder case 3 (0.95 μm water band depth), case 4 (1.15 μm water band depth), and case 5 (1.4 μm water band depth) after vegetation was detected in Group 3. This is a Tetracorder standard product with expert system 5.27e1. (g). Vegetation red-edge position (left image) and approximate true color (right image). This is a Tetracorder Case 1 analysis after vegetation was detected in Group 3. This is a Tetracorder standard product with expert system 5.27e1.