<title>Contrast-limited target acquisition: atmospheric and motion effects</title>

Abstract

In this paper, the incorporation of atmospheric aerosol and turbulence blur and motion blur into visible, near infrared, and thermal infrared target acquisition modeling is considered. Here, we show how the target acquisition probabilities and, conversely, the ranges at which objects can be detected are changed by the inclusion of these real-life environmental effects whose blur is often significantly greater than that of imaging system hardware. It is assumed that images are contrast-limited rather than noise-limited, as is indeed the case with most visible, near infrared (IR) and thermal JR sensors. For short focal lengths with low angular magnification, such environmental blur effects on target acquisition are negligible. However, for longer focal lengths with large angular magnification, resolution is limited by them and this has a strong adverse effect on target acquisition probabilities, times and ranges. The considerable improvement possible with image correction for such environmental blur automatically in a fraction of a second is significant for contrast-limited imaging, and is discussed here too. Knowledge of such environmental MTF is essential to good system design and is also very useful in image restoration for any type of target or object.