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Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 14, Iss. 20 — Oct. 2, 2006
  • pp: 9130–9141

Identification and classification of chemicals using terahertz reflective spectroscopic focal-plane imaging system

Hua Zhong, Albert Redo-Sanchez, and X.-C. Zhang  »View Author Affiliations

Optics Express, Vol. 14, Issue 20, pp. 9130-9141 (2006)

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We present terahertz (THz) reflective spectroscopic focal-plane imaging of four explosive and bio-chemical materials (2, 4-DNT, Theophylline, RDX and Glutamic Acid) at a standoff imaging distance of 0.4 m. The 2 dimension (2-D) nature of this technique enables a fast acquisition time and is very close to a camera-like operation, compared to the most commonly used point emission-detection and raster scanning configuration. The samples are identified by their absorption peaks extracted from the negative derivative of the reflection coefficient respect to the frequency (-dr/dv) of each pixel. Classification of the samples is achieved by using minimum distance classifier and neural network methods with a rate of accuracy above 80% and a false alarm rate below 8%. This result supports the future application of THz time-domain spectroscopy (TDS) in standoff distance sensing, imaging, and identification.

© 2006 Optical Society of America

OCIS Codes
(070.4560) Fourier optics and signal processing : Data processing by optical means
(100.5010) Image processing : Pattern recognition
(120.6200) Instrumentation, measurement, and metrology : Spectrometers and spectroscopic instrumentation
(300.6270) Spectroscopy : Spectroscopy, far infrared

ToC Category:
Imaging Systems

Original Manuscript: August 1, 2006
Revised Manuscript: September 11, 2006
Manuscript Accepted: September 12, 2006
Published: October 2, 2006

Virtual Issues
Vol. 1, Iss. 11 Virtual Journal for Biomedical Optics

Hua Zhong, Albert Redo-Sanchez, and X.-C. Zhang, "Identification and classification of chemicals using terahertz reflective spectroscopic focal-plane imaging system," Opt. Express 14, 9130-9141 (2006)

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