Image simulation of remote sensing in rugged terrain for hyperion data

Terrain is one of the important factors which could badly affect the remote sensing image. In rugged terrain, the irradiance at ground level,including the solar direct irradiance, the solar diffuse irradiance and the surrounding terrain reflected irradiance,is influenced by terrain severely. It is valuable to investigate the image simulation of remote sensing in rugged terrain. In this paper, a modified method for the precise simulation of at-sensor radiance is developed. In the calculation of the solar direct irradiance, the shade factor is modified to a decimal between 0 and 1 instead of the binary factor 0 or 1 to indicate the pixels that are partly receiving solar direct beam. Reindl's solar diffuse irradiance method is introduced to account for the horizon brightness component ignored by other methods. Proy's accurate surrounding reflected irradiance model is introduced as well. Simulation of radiance image in Qulong, Tibet is carried out using Hyperion reflectance data and associated DEM to evaluate the modified method's precision. Spectra and statistics characteristics of simulation radiance image are compared with original radiance image. Comparisons indicate the modified method can achieve fine results and the average of maximum error is 10.9%.