Title :
APEX: Radiometry under spectral shift conditions
Author :
Hueni, A. ; Schlaepfer, D. ; Jehle, M.
Author_Institution :
Remote Sensing Labs., Univ. of Zurich, Zurich, Switzerland
Abstract :
The APEX airborne imaging spectrometer has been shown to exhibit spectral shifts during in-flight conditions, linked to changes in the nitrogen gas density within the APEX optical subunit. These shifts lead to features in the recorded spectra caused by the dichroic coating used as a beam splitter between VNIR and SWIR channels. Consequently dichroic features are no longer compensated for by the radiometric calibration coefficients obtained under laboratory conditions. This paper presents results of a numerical simulation that can model the impact of spectral shifts on radiometry. As a consequence the APEX sensor model has been upgraded and according correction functions have been implemented in the APEX level 1 processor to compensate for shift dependent changes in radiometry due to the dichroic coating.
Keywords :
calibration; geophysical equipment; numerical analysis; optical beam splitters; radiometry; APEX airborne imaging spectrometer; APEX level 1 processor; APEX optical subunit; APEX sensor model; SWIR channel; VNIR channel; beam splitter; correction functions; dichroic coating; in-flight conditions; laboratory conditions; nitrogen gas density; numerical simulation; radiometric calibration coefficients; spectral shift conditions; Atmospheric modeling; Calibration; Coatings; Laboratories; Optical imaging; Radiometry; Airborne Imaging Spectroscopy; Instrument Calibration; Spectral Shifts;
Conference_Titel :
Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International
Conference_Location :
Quebec City, QC
DOI :
10.1109/IGARSS.2014.6946692
