Assessment of radiometric correction methods for ADS40 imagery

This article presents the results of an assessment of radiometric correction methods of images taken by the large-format aerial, photogrammetric, multispectral pushbroom camera Leica Geosystems ADS40. The investigation was carried out in the context of the multi-site EuroSDR project “Radiometric aspects of digital photogrammetric images”. Images were collected at the forestry research test site Hyytiälä, Finland in August, 2008. Two processing workflows were evaluated: one based on the photogrammetric software Leica XPro, which in radiometric processes relies on physical modeling and information collected from the imagery only, and one based on ATCOR-4, which is software dedicated to physical atmospheric correction of airborne multi-, hyperspectral and thermal scanner data, and can be operated either with or without in-situ reflectance and atmospheric observations. Outputs of these processes are reflectance images. Three participants processed the data with several processing options which resulted in a total of 12 different radiometrically corrected reflectance images. The data analysis was based on field and laboratory reflectance measurements of reference reflectance targets and field measurements of permanent targets (asphalt, grass, gravel). Leica XPro provided up to 5 % reflectance accuracy without any ground reference and ATCOR-4 provided reflectance accuracy better than 5 % with vicarious inflight radiometric calibration of the sensor. The results show that the radiometric correction of multispectral aerial images is possible in an efficient way in the photogrammetric production environment.