Incorporation of atmospheric blurring effects in target acquisition modeling

Recent investigation of atmospheric modulation transfer function (MTF) in the thermal range has shown significant spatial frequency dependence. This dependence is related to aerosol forward scatter as well as absorption effects, shown to be primary contributors to the blur in thermal imaging through the atmosphere. In this paper, the night vision laboratory (CNVEO) target acqusition search model is revised to include atmospheric MTF spatial frequency dependence. It is shown how the target acquisition probabilities and, conversly, the range at which targets can be detected are changed by the inclusion of atmospheric effects. Under weak turbulence conditions target acquisition probabilities are better than predicted by the CNVEO model at shorter ranges. For very strong turbulence, as at midday on hot days, target acquisition probabilities decrease. The improvement possible by correcting for this blur automatically in real time is significant.