INCORPORATION OF ATMOSPHERIC BLURRING EFFECTS IN TARGET ACQUISITION MODELING OF THERMAL IMAGES

Recent investigation of atmospheric modulation transfer function (MTF) in the thermal IR has shown significant spatial frequency dependence. This dependence is related to aerosol forward scatter as well as part iculate absorption effects, shown to be primary contributors to blur i n thermal imaging through the atmosphere. One of the primary models fo r target acquisition is the Institute for Defence Analysis variant of the Night Vision Laboratory (IDA/NVL) target acquisition model; in thi s paper, this model is revised to include atmospheric MTF spatial freq uency dependence. It is shown how the target acquisition probabilities and, conversly, the range at which targets can be detected are change d by the inclusion of atmospheric effects. Under weak turbulence condi tions target acquisition probabilities are better than predicted by th e IDA/NVL model at shorter ranges. For very strong turbulence, as at m idday on hot days, target acquisition probabilities decrease. Effects of real-time image restoration are discussed.