Imaging Vertically Through the Atmosphere: Restoration of Satellite Images Based on Atmospheric MTF Evaluation

When carrying out satellite images by imaging vertically through the atmosphere, distortions and blur arise as a result of turbulence and aerosols. Contrast is reduced by path radiance. The recently developed atmospheric Wiener filter, which corrects for turbulence blur, aerosol blur, and path radiance simultaneously, is implemented in digital restoration of Landsat imagery over seven wavelength bands of the satellite instrumentation. A required input is weather. Restoration is most impressive for high optical depth situations, which cause larger blur. Restoration improves both smallness of size of resolvable detail and contrast. Turbulence modulation transfer function (MTF) is calculated from meteorological data. Aerosol MTF is consistent with optical depth. The product of the two yields atmospheric MTF, which is implemented in the atmospheric Wiener filter. Turbulence blur, aerosol blur, and path radiance contrast loss are all corrected simultaneously, as if there were no intervening atmosphere. The primary source of atmospheric blur is seen to be aerosol forward scatter of light. Restorations are shown for various wavelength bands and are quite apparent even under clear weather conditions.