StarDICE II: Calibration of an Uncooled Infrared Thermal Camera for Atmospheric Gray Extinction Characterization

Autor: Kélian Sommer, Bertrand Plez, Johann Cohen-Tanugi, Sylvie Dagoret-Campagne, Marc Moniez, Jérémy Neveu, Marc Betoule, Sébastien Bongard, Fabrice Feinstein, Laurent Le Guillou, Claire Juramy, Eduardo Sepulveda, Thierry Souverin
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Sensors, Vol 24, Iss 14, p 4498 (2024)
Druh dokumentu: article
ISSN: 1424-8220
DOI: 10.3390/s24144498
Popis: The StarDICE experiment strives to establish an instrumental metrology chain with a targeted accuracy of 1 mmag in griz bandpasses to meet the calibration requirements of next-generation cosmological surveys. Atmospheric transmission is a significant source of systematic uncertainty. We propose a solution relying on an uncooled infrared thermal camera to evaluate gray extinction variations. However, achieving accurate measurements with thermal imaging systems necessitates prior calibration due to temperature-induced effects, compromising their spatial and temporal precision. Moreover, these systems cannot provide scene radiance in physical units by default. This study introduces a new calibration process utilizing a tailored forward modeling approach. The method incorporates sensor, housing, flat-field support, and ambient temperatures, along with raw digital response, as input data. Experimental measurements were conducted inside a climatic chamber, with a FLIR Tau2 camera imaging a thermoregulated blackbody source. The results demonstrate the calibration effectiveness, achieving precise radiance measurements with a temporal pixel dispersion of 0.09 W m−2 sr−1 and residual spatial noise of 0.03 W m−2 sr−1. We emphasize that the accuracy of scene radiance retrieval can be systematically affected by the camera’s close thermal environment, especially when the ambient temperature exceeds that of the scene.
Databáze: Directory of Open Access Journals
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