Influence of moderate-to-strong non-Kolmogorov turbulence on the imaging system by atmospheric turbulence MTF

The atmospheric turbulence modulation transfer function (MTF) which describes the degrading effect of atmospheric turbulence on imaging system is investigated theoretically for plane and spherical waves propagating through moderate-to-strong non-Kolmogorov turbulence. In the investigation, the effective non-Kolmogorov spectral model is adopted, and it modifies the conventional non-Kolmogorov spectral model with a modified frequency filter function. The new expressions cover a more wide range of non-Kolmogorov turbulence strength, and reduce correctly to previously published analytic expressions for both weak non-Kolmogorov turbulence and moderate-to-strong (or strong) Kolmogorov turbulence cases. Numerical calculations show that the MTF model derived in this work deviates from those obtained with the Rytov theory as turbulence strength increases up to moderate-to-strong (or strong) non-Kolmogorov turbulence regime.