Simulated reflectance technique for ATM image enhancement
Abstract. The thermal band of the Airborne Thematic Mapper (ATM) has the same spatial resolution as that of the reflective spectral bands and therefore can be used together with other bands without degrading the resolution as happens with Landsat TM. Here we show that the total solar irradiance on the land surface can be simulated by a properly weighted summation of the thermal band and all the reflective spectral bands. The simulated reflectance as well as emittance can then be derived from the relation between irradiance, thermal emittance, spectral reflectance and albedo based on a simplified energy conservation model of solar radiation incident on a land surface. Compared with other methods for spectral enhancement and topography suppression, such as ratio and logarithmic residual, this method has the advantage of conserving surface albedo information and thus produces a reasonable simulation of reflectance.