Radiometric Cross-Calibration of Low-Cost Multispectral and Hyperspectral Sensors Under Variable Sun-Sensor Geometry for UAV Remote Sensing Applications

Abstract

In this work, the radiometric cross-calibration of low-cost multi/hyperspectral sensors for UAV remote sensing applications with consideration of sun-sensor geometry effects is investigated. First, the standard BRDF model is used to deduce the radiometric correction factors associated to the sun-sensor geometry. Then, the LRM model is used to calibrate the hyperspectral measurements from the corrected multispectral ones. In order to test this methodology, an agriculture-type UAV with integrated multispectral camera and a point micro-spectrometer are used. Results of the corrected irradiance based calibration in a set of four reference targets under clear sky conditions show a reduction of up to 1:3 in the mean absolute reflectance estimation error (MAE) with respect to the reflectance based calibration without irradiance normalization.