Detection of Liquids on Surfaces using Long Wave Infrared Hyperspectral Imaging Spectroradiometer

The U.S. military is investing heavily in the development of standoff chemical warfare agent (CWA) sensors for battlefield use. The principal purpose of these sensors is to enable contamination avoidance. While CWAs are typically dispersed as droplets or aerosols, sensors in development and production for field deployment are designed primarily for detection of agents in the vapor phase. As such, these sensors offer limited advanced warning capability, as they are largely insensitive to the presence of low vapor pressure CWAs such as HD and VX, which are encountered primarily as liquids and droplets on surfaces. Physical Sciences Inc. proposes to modify an Adaptive Infrared Imaging Spectroradiometer (AIRIST), an LWIR hyperspectral imaging sensor, to enhance its utility for standoff detection of liquid contamination on surfaces. AIRIS has proven to be highly effective for standoff chemical vapor detection and has demonstrated standoff detection of liquids on several occasions. Field test data using CWA simulants suggests that VX may be detected at <0.1 g/m2 using the core AIRIS technology. The standoff detection range of sensors based on passive sensing of LWIR radiation, such as AIRIS, is limited by line-of-sight transmission through the atmosphere, typically 3-5 km in a horizontal viewing geometry.