Performance analysis of gated SWIR imaging system for target against plume background

In targets like airplanes, rockets, or missiles, there are both the target and the plume. When tracking the target through imaging optics, the plume can become background depending on the perspective of the optical system. When plumes are in the background, the target image may be obscured by the saturation of the plume signals. In this study, a range-gated short-wave infrared (SWIR) imaging system was considered for the acquisition and tracking of the target against the plume background. The target signal is the illumination laser light reflected from the target and the background signal is the self-radiation of the plume. We considered a method using the illumination laser energy and the detector integration time to increase the target signal and decrease the plume signal. We analyzed the system signal-to-noise ratio (SNR) as a function of the illumination laser energy and the detector integration time. As a result, we derived system design specifications satisfying the SNR greater than 2.5.