A Vicarious Calibration of the Probe-1 Hyperspectral Sensor

Analysis of Probe-1 hyperspectral data obtained during July 1998 revealed that neither the spectroscopic nor the radiometric laboratory calibrations supplied with the data were applicable, presumably because the sensor had suffered an undocumented opto-mechanical realignment between the calibration and the flight. In this paper the calculation of a new set of calibration coefficients is described, based upon the simultaneous acquisition of high-resolution GER3700 field spectra for a calibration site within the Probe-1 image. For the calibration calculations, an average ground-based reflectance spectrum for the target area was convolved and resampled to match the spectral characteristics of the Probe-1 sensor. The MODTRAN3 radiative-transfer code was used to correct the Probe-1 radiance spectra to surface reflectance, and an iterative numerical technique was applied to adjust the Probe-1 radiometric coefficients, to reduce the absolute reflectance difference between the GER3700 and Probe-1 spectra for the calibration site to 0.02 percent. This technique for the vicarious calibration of hyperspectral data has been implemented into the Imaging Spectrometer and Data Analysis System developed at the Canada Centre for Remote Sensing (CCRS).