Detection of Chemicals in Mixed, Two-Dimensional Raman Spectra
NAVAL RESEARCH LAB WASHINGTON DC
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Recently, researchers at the Naval Research Laboratory have developed the SWORrD system for measuring two-dimensional Raman Spectra. The device consists of a tunable 2d ultraviolet laser that illuminates the sample at various wavelengths 210-300 nm and collects a single Raman spectrum at each laser wavelength. The single spectra are combined to form a two-dimensional spectrum laser wavelength by scattered wavenumber. In this paper we introduce a novel method for the detection of known agents targets within measured 2d spectra. Our method is bases on linear mixed pixel techniques from hyperspectral imagery in particular, we generalize the Adaptive Subspace Detector ASD to a form suitable for SWORrD samples. Our detector uses the individual laser runs to define a set of points within wavenumber space the set of points corresponding to a 2d spectra defines a particular subspace that contains each material. These subspaces are then used with ASD to identify targets. We include experimental results using real-world data to illustrate our results.
- Atomic and Molecular Physics and Spectroscopy