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A methodology is presented that, for the first time, allows characterization of the atmospheric effects on the propagation of target contrast. The two elements of target contrast are inherent contrast as seen closeup or in the near-field and propagated contrast as produced by the degradation of the inherent target and background radiation in propagating from closeup to engagement range or in the far-field. Atmospheric effects can produce dynamic changes in these two elements. Examples of these changes are presented as well as features or metrics of target contrast which can be used to quantify them. The technology for quantifying changes in target contrast was developed at the U.S. Army Atmospheric Sciences Laboratory, and the equipment is termed the Target Contrast Characterizer (TCC). The basic concept is to simultaneously compare matched images from two imagers--one in the near-field and the other in the far-field--along a common line of sight. For example, if one imager with a 1X lens is used to view a target from 100 m and a second imager is used to view the same target simultaneously with a 10X lens from 1 km, their fields of view will have a common window in the target plane. The ability to compare the images from these two imagers in real-time was made possible by the use of a unique real-time image processing system. This system was developed in the course of an in-house laboratory independent research project of the authors. The application of this real-time image processor to one-to-one comparison of the two matched target scenes allows, for the first time, the separation of the changes in target contrast due to propagation between the near-field and the far-field positions from the changes in the inherent or near-field contrast. In addition, temporal changes of the inherent contrast can be quantified by monitoring the change in the near-field imagery. The TCC already has a wide range of military applications which include assisting the development of aided target recognition systems as well as improved design and performance testing of weapons used to engage enemy targets. The real-time image processing techniques, proof of principle guidelines, and several applications of this technology are detailed.
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