Determination of the angular sensitivity of a multispectral line scanner from image data

The DAEDALUS AADS 1268 is a multispectral line scanner with 11 spectral channels and 716 pixels per line. This paper presents a post-flight calibration method to correct the data for dependence of the detector sensitivity on the scanning angle. An area has to be found where only negligible BRDF effects are expected across the principle plane for zenith angles smaller than the maximum scanning angle. The area does not need to be homogenous, but it must extend over a whole scan line. The runway of the Nuremberg airport was chosen. The pixels of the scan line acquired when crossing the runway at right angles were divided by the respective pixels of the perpendicular overflight after georegistration. The resulting angular sensitivity functions show variations up to 15% (depending on channel), similar to findings from a laboratory experiment three years earlier. A comparison with laboratory data from a DAEDALUS operated in Australia shows similar results, except for channels 2 and 8