Testing the Radiometric Performance of Digital Photogrammetric Images: Vicarious vs. Laboratory Calibration on the Leica ADS40, a Study in Spain

This paper deals with the vicarious calibration of a linear array sensor, A DS40, and the comparison and analysis with the laboratory calibration provided by the manufacturer. For this purpose, a specific test field located in the city of Avila (Spain) was designed for the two different flights performed during the 8th and 9th of April, 2010 with a spatial resolution of 10 cm and 25 cm, respectively. In addition, a reflectance measurement campaign was performed during the flight using an ASD FieldSpec 3 Hi-Res spectroradiometer, observing a group of 24 targets which included natural and artificial surfaces. Two study cases were considered: with and without atmospheric correction. In order to take into account atmospheric effects, the reflectance method based on the radiative transfer model was applied to establish the relationship between sensor and ground magnitudes. Compared to the calibration results provided by the manufacturer, the results of the vicarious calibration are better. In particular, the root-mean-square grey value error (RMSE) reached through the vicarious calibration in the different reference surfaces is lower than for the laboratory calibration, which considers always the same atmospheric model. Finally, analyzing the stability of the calibration and its relation with the flying height, the calibration of the lower flight (10 cm) was extrapolated to the 25 cm flight, obtaining similar accuracies.