Imaging through the atmosphere for airborne reconnaissance

Turbulence, atmospheric background, and aerosol forward scattering modulation transfer functions (MTFs) are analyzed with regard to both low elevation remotely piloted vehicles and high elevation reconnaissance applications. Turbulence is seen to limit image quality only at very high spatial frequencies, where degradation is likely to take place anyway as a result of vibration and diffraction. Background and aerosol MTFs limit low spatial frequency contrast as well. However, this can be overcome by proper selection of the imaging wavelength and of operation timing. This analysis can aid in sensor selection for system design from the standpoints of both wavelength selection and sensor resolution. Because this analysis includes the effects of weather changes on image propagation through the atmosphere, it can aid in selecting operation timing on the basis of weather forecasts, with a view toward optimizing expected resolution.