Effects of aerosol forward scatter on the long- and short-exposure atmospheric coherence diameter Academic Article uri icon

abstract

  • An experimental investigation of the atmospheric coherence diameter is presented in order to examine the relative effects of turbulence and aerosol forward scattering The investigation includes measurements through the open atmosphere for pathlengths of several kilometres. In addition to turbulence degradation of the atmospheric coherence diameter. it is shown here that aerosol forward scattering also causes severe limitations, particularly for short exposures. Two methods, direct (spatial domain) and indirect (spatial frequency domain), for measuring the atmospheric coherence diameter are presented. The methods are theoretically and experimentally independent. The results of both methods are in very good agreement, emphasizing meamrement reliability. It is shown that, in contradiction to turbulence, aerosols afect light coherence identically for both short and long exposures. Experimenial results during rather extreme atmospheric conditions such as fog are pieseated too. The results here are applicable to cost-effective imaging system design involving aperture size, and to predicting imaging system performance through the atmosphere

publication date

  • January 1, 1994