Experimental comparison of imaging illumination modes for long-range target imaging in Near-IR verse SWIR bands

Collecting sufficient photon flux to clearly observe a target against the background and sensor noise is critical for long-range target imaging. The sensitivity can be characterized by signal-to-noise ratio which can be derived from radiometry. There are many factors that affect the radiometry of an imaging system including type of illumination source, atmospheric effects and the operating wavelength or band. This paper compares passive imaging and active imaging for long-range targets in near infrared (NIR) verse shortwave infrared (SWIR) bands. Passive imaging uses direct sunlight as an illumination source to take an image of a target. For active imaging, we investigate continuous wave (CW) and pulsed laser illumination during both day and night operations. LRG illumination provides temporal controls to reduce atmospheric backscatter and distant background in order to maximize contrast to noise ratio (CNR). This study compares experimental data collected over propagation distances up to 1km against radiometric models implemented analytically and numerical modelling implemented in the Night Vision Integrated Performance Model (NV-IPM). This comparison is performed for each illumination mode using both Near-IR and SWIR bands.