Imaging Through Obscurants

The US Fleet Forces are often present in congested waterways throughout the world for a variety of humanitarian and military purposes. To maintain situational awareness (SA) and to support target detection, tracking, and identification, electro-optical (EO) and infrared (IR) sensors could be employed for their superior resolution and image-forming mode of operation, in contrast to radar. However, the short wavelengths associated with EO-IR make imaging far more susceptible to performance degradation from scattering by ubiquitous water-based aerosols, which typically generate a large, non-information carrying, background radiation that overwhelms the ballistic signals that do carry information about the scene. Imaging through dense fog is the intrinsic hard problem, as a strongly scattering medium fills the entire working volume. Imaging through cloud layers, haze, or fog can be improved via post processing by exploiting prior information about the scene, but the deleterious effect of the scattering medium on the signal-to-background ratio remains the key limitation, which depends on the image acquisition mode as well as the optical properties of the water-based aerosols. The ONR Code 312 EO-IR Technologies Focus Area seeks information on both active and passive solutions to imaging through obscurants, including fog, haze, rain, and snow, but excluding dust or smoke. Active imaging techniques employing, for example, structured laser-light illumination and/or temporal gating are of interest, along with passive imaging techniques employing, for example, a judicious choice of spectral band(s), polarization diversity, high-speed multi-frame acquisition, or other mode of acquisition together with advanced processing to achieve a substantial overall improvement. Solutions that invoke unique material (e.g., spectroscopic) properties of relevant obscurants would also be of interest. Solutions can exploit all or any portion of the electromagnetic spectrum ranging from the UV to the far IR, including the conventional bands referred to as electro-optic (EO), near-infrared (NIR), short-wave IR (SWIR), mid-wave IR (MWIR), and long-wave IR (LWIR), but excluding active mm-wave operation.