TY - GEN
T1 - Accuracy assessment for the radiometric calibration of imaging sensors using preflight techniques relying on the sun as a source
AU - Thome, K.
AU - Czapla-Myers, J.
AU - Kuester, M.
AU - Anderson, N.
PY - 2008
Y1 - 2008
N2 - The Remote Sensing Group (RSG) at the University of Arizona has performed high-accuracy radiometric calibration in the laboratory for more than 20 years in support of vicarious calibration of space-borne and airborne imaging sensors. Typical laboratory calibration relies on lamp-based sources which, while convenient to operate and control, do not simulate the solar spectrum that is the basic energy source for many of the imaging systems. Using the sun as a source for preflight radiometric calibration reduces uncertainties caused by the spectral mismatch between the preflight and inflight calibration, especially in the case in which a solar diffuser is the inflight calibration method. Difficulties in using the sun include varying atmospheric conditions, changing solar angle during the day and with season, and ensuring traceability to national standards. This paper presents several approaches using the sun as a radiometric calibration source coupled with the expected traceable accuracies for each method. The methods include direct viewing of the solar disk with the sensor of interest, illumination of the sensor's inflight solar diffuser by the sun, and illumination of an external diffuser that is imaged by the sensor. The results of the error analysis show that it is feasible to achieve preflight calibration using the sun as a source at the same level of uncertainty as those of lamp-based approaches. The error analysis is evaluated and compared to solar-radiation-based calibrations of one of RSG's laboratory-grade radiometers.
AB - The Remote Sensing Group (RSG) at the University of Arizona has performed high-accuracy radiometric calibration in the laboratory for more than 20 years in support of vicarious calibration of space-borne and airborne imaging sensors. Typical laboratory calibration relies on lamp-based sources which, while convenient to operate and control, do not simulate the solar spectrum that is the basic energy source for many of the imaging systems. Using the sun as a source for preflight radiometric calibration reduces uncertainties caused by the spectral mismatch between the preflight and inflight calibration, especially in the case in which a solar diffuser is the inflight calibration method. Difficulties in using the sun include varying atmospheric conditions, changing solar angle during the day and with season, and ensuring traceability to national standards. This paper presents several approaches using the sun as a radiometric calibration source coupled with the expected traceable accuracies for each method. The methods include direct viewing of the solar disk with the sensor of interest, illumination of the sensor's inflight solar diffuser by the sun, and illumination of an external diffuser that is imaged by the sensor. The results of the error analysis show that it is feasible to achieve preflight calibration using the sun as a source at the same level of uncertainty as those of lamp-based approaches. The error analysis is evaluated and compared to solar-radiation-based calibrations of one of RSG's laboratory-grade radiometers.
KW - Absolute-radiometric calibration
KW - Atmospheric correction
KW - Vicarious calibration
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U2 - 10.1117/12.795681
DO - 10.1117/12.795681
M3 - Conference contribution
AN - SCOPUS:52349106305
SN - 9780819473011
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Earth Observing Systems XIII
T2 - Earth Observing Systems XIII
Y2 - 11 August 2008 through 13 August 2008
ER -