RADIOMETRIC CORRECTION OF MULTITEMPORAL THEMATIC MAPPER DATA FOR USE IN AGRICULTURAL LAND-COVER CLASSIFICATION AND VEGETATION MONITORING

Many remote sensing applications, especially multitemporal approaches, require radiometric corrections of image data in which radiometric normalization to standard conditions and modelistic atmospheric corrections are often considered as alternative solutions. Successful radiometric normalization depends on the availability of suitable reference targets within the scenes under considerations, which may be critical. It is demonstrated that even simplified atmospheric correction modelling can provide a valuable alternative solution. We present an atmospheric correction approach for Thematic Mapper data, which is based solely on the evaluation of scene information and may therefore be considered operational. The method is based on the determination of aerosol optical thickness from histogram minima and clear water targets. Atmospheric conditions are assumed constant over the scene, but their variation with the Sun-to-satellite scattering angle is accounted for. The environment effect is approximately corrected for each pixel. The accuracy of the method is analysed with respect to ground measurements, and a between-scene comparison of modelled reflectance factors from invariant targets. These first results indicate a precision of the retrieved reflectance factors which is suitable for a quantitative image analysis and a comparison with radiometric field data.