Real-Time, Reconfigurable, Handheld Molecular Chemical Imaging Sensing for Standoff Detection of Threats

摘要

As the nature of explosive, chemical and narcotic threats become more pervasive and lethal to innocent bystanders andunsuspecting military and law enforcement authorities, there is a growing demand for rapid and effective detection ofmaterials in real-time with a high degree of autonomy at safe distances. In an effort to address this need, ChemImage hasbeen developing novel, adaptable, short-wave infrared (SWIR) molecular chemical imaging systems for real-timeanalysis of complex environments, including for detection of hazardous materials (e.g., explosives, chemical warfareagents, drugs of abuse). At the heart of these systems is the Conformal Filter (CF), which is a liquid crystal (LC)-basedtunable filter that transmits multi-band waveforms. Building on concepts of multivariate optical computing, the CF istuned electro-optically and dynamically to mimic the functionality of a discriminant vector for classification. Theresulting integrated detector response approximates the detection response of conventional hyperspectral imaging withonly two discrete measurements instead of hundreds to thousands. Real-time detection is achieved by operating two CFsin tandem within a dual polarization (DP) system, which exploits the polarization sensitivity of the LC filters and allowsfor simultaneous acquisition of the compressed hyperspectral imagery.This paper will discuss the development, characterization, and test results of a prototype, handheld CF sensor, with a focuson its application to explosives, chemical and narcotic threat detection.