Stochastic model-based processing for detection of small targets in non-Gaussian natural imagery

Stochastic background models incorporating spatial correlations can be used to enhance the detection of targets in natural terrain imagery, but are ge nerally difficult to apply when the statistics are non-Gaussian, Recently C happle and Bertilone III proposed a simple stochastic model for images of n atural backgrounds based on the pointwise nonlinear transformation of Gauss ian random fields, and demonstrated its effectiveness and computational eff iciency in modeling the textures found in natural terrain imagery acquired from airborne IR sensors. In this paper, we show how this model can be used to design algorithms that detect small targets (up to several pixels in si ze) in natural imagery by identifying anomalous regions of the image where the statistics differ significantly from the rest of the background. All of the model-based algorithms described here involve nonlinear spatial proces sing prior to the final decision threshold, Monte Carlo testing reveals tha t the model-based algorithms generally perform better than both the adaptiv e threshold filter and the generalized matched filter for detecting Low-con trast targets, despite the fact that they do not require the target statist ics needed for constructing the matched filter.