NVThermIP vs TOD: matching the target acquisition range criteria

Currently, three major approaches exist to predict Target Acquisition (TA) performance with thermal imagers: i) the TOD laboratory method and model, ii) the NVThermIP model and iii) the MTDP lab method and TRM3 model. In this study, TOD measurements, TOD predictions and NVThermIP predictions are compared for a number of simulated sensors ranging from very well-sampled to highly under-sampled. A similar comparison study using a previous (2001) version of the NVTherm model showed huge differences in sensor performance predictions (Bijl, Hogervorst & Valeton; SPIE Proceedings Vol. 4719, 51-62; 2002). The most important result of the current study is that NVThermIP predictions are much closer to the TOD measurements and predictions than those of its predecessor, showing limited effect of under-sampling. Quantitatively, TA range predictions for well-sampled imagers are equivalent and NVThermIP predicts 25% longer ranges than the TOD model for under-sampled imagers with MP = 0.35∙ VP and β = 1.25, where VP are the criteria published with NVThermIP to predict TA range for a variety of target sets, MP are the corresponding TOD magnification factors, and β is the slope of the probability vs range function in the TOD target acquisition model. Which method yields the best predictions under which circumstances should be the subject of an empirical study using TA performance for real targets. It is therefore advised that all available TA validation data be presented in such a way that all models and methods can be compared to the data directly and unambiguously.