title: Infrared differential-absorption Mueller matrix spectroscopy and neural network-based data fusion for biological aerosol standoff detection.
abstract: An active spectrophotopolarimeter sensor and support system were developed for a military/civilian defense feasibility study concerning the identification and standoff detection of biological aerosols. Plumes of warfare agent surrogates gamma-irradiated Bacillus subtilis and chicken egg white albumen (analytes), Arizona road dust (terrestrial interferent), water mist (atmospheric interferent), and talcum powders (experiment controls) were dispersed inside windowless chambers and interrogated by multiple CO(2) laser beams spanning 9.1-12.0 microm wavelengths (lambda). Molecular vibration and vibration-rotation activities by the subject analyte are fundamentally strong within this "fingerprint" middle infrared spectral region. Distinct polarization-modulations of incident irradiance and backscatter radiance of tuned beams generate the Mueller matrix (M) of subject aerosol. Strings of all 15 normalized elements {M(ij)(lambda)/M(11)(lambda)}, which completely describe physical and geometric attributes of the aerosol particles, are input fields for training hybrid Kohonen self-organizing map feed-forward artificial neural networks (ANNs). The properly trained and validated ANN model performs pattern recognition and type-classification tasks via internal mappings. A typical ANN that mathematically clusters analyte, interferent, and control aerosols with nil overlap of species is illustrated, including sensitivity analysis of performance.
authors.affiliation: United States Army Research, Development, and Engineering Command (RDECOM) Edgewood Chemical Biological Center (ECBC) Research and Technology Directorate, Attention: RDCB-DRD-L, 5183 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010-5424, USA. arthur.carrieri@us.army.mil
authors.forename: Arthur H
authors.initials: AH
authors.lastname: Carrieri
authors.forename: Jack
authors.initials: J
authors.lastname: Copper
authors.forename: David J
authors.initials: DJ
authors.lastname: Owens
authors.forename: Erik S
authors.initials: ES
authors.lastname: Roese
authors.forename: Jerold R
authors.initials: JR
authors.lastname: Bottiger
authors.forename: Robert D
authors.initials: RD
authors.lastname: Everly
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Hung
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000391:Air Microbiology; D000393:Air Pollutants / Q000032:analysis; D000818:Animals; D001412:Bacillus subtilis / Q000302:isolation & purification; D054045:Biological Warfare Agents; D023482:Bioterrorism; D004867:Equipment Design; D006801:Humans; D016571:Neural Networks, Computer; D055620:Optical Phenomena; D010047:Ovalbumin / Q000032:analysis; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D054045:Biological Warfare Agents; D010047:Ovalbumin