Atmospheric and Terrain Correction of Ikonos Imagery Using Atcor3

When ordering very high resolution (VHR) imagery of IKONOS or QuickBird a cloud coverage up to 20 % within the scenes has to be accepted. This indicates the high impact of atmospheric conditions to VHR imagery. Beside clouds the images are influenced by haze oftentimes. This haze could be removed using new atmospheric correction algorithms, which were not available for VHR data so far. Furthermore, effects caused by the terrain are influencing the classification quality of VHR imagery in particular in areas of high relief energy. These effects can be eliminated using a high resolution digital elevation model (DEM) within the correction process. The main reason for atmospheric correction is that multi-temporal scenes become comparable, because digital numbers are substituted by surface reflectances. Thus, classification schemes developed once can easily be applied to other subsequent recorded scenes. The haze removal and atmospheric-topographic correction algorithms are implemented in the software ATCOR3 which is available as an extension of standard remote sensing software, like ERDAS IMAGINE 8.7 or PCI Geomatica, and as stand-alone software based on IDL as well. The software was tested and improved in cooperation between users and the developers using IKONOS data, but it is also applicable to other VHR data (QuickBird etc.). Within the paper the procedure and the results of correcting two hazy IKONOS scenes will be demonstrated and evaluated from an end-user’s point of view. On the other hand the terrain correction of this imagery using a VHR laser scanning DEM is in the focus of the investigation. * Corresponding author.