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Proceedings Paper

The effects of two noises from passive FTIR (Fourier transform infrared) spectroscopy system on the detection probability of stand-off hazardous compounds with passive Fourier transform infrared spectroscopy system using Michelson interferometer
Author(s): Hee Kyung Ahn; Hong Jin Kong; Kang Sup Shim
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Paper Abstract

An Fourier Transform Infra-Red(FTIR) spectrometry has played an significant role in a variety of fields in recent years. In particular, FTIR spectrometer technology has been adopted in passive remote sensing system to predict detection probabilities of stand-off hazardous compounds. There are three steps to detect hazardous compounds. Firstly, MODerate spectral resolution atmospheric TRANsmittance(MODTRAN) algorithm is used to calculate spectral radiances of background and atmosphere affected by hazardous compounds. It transfers a difference of spectral radiance between background and hazardous compounds existing region to FTIR spectroscopy system. Secondly, FTIR spectrometry system collects an interferogram which represents spectral radiances respective to given time intervals (reciprocal of wavenumber) and sends it to signal processing part. Lastly, the signal processing part performs Fourier Transformation on the interferogram and identifies the spectral radiance with reference data from gas library by using Spectral Angle Mapper(SAM) algorithm which results in visualizing the hazardous gases. However, there are some noises which affect the interferogram and the spectrum in practice. Specifically, there are two main noises which have critical effects on the interferogram and the spectrum by reducing its Signal to Noise Ratio(SNR) such as detector noise, jitter of moving mirror and optics misalignment. In this paper, a theory of the effects of the detector noise and the jitter of moving mirror on the interferogram and its demonstration through simulation are presented.

Paper Details

Date Published: 26 May 2011
PDF: 9 pages
Proc. SPIE 8024, Advanced Environmental, Chemical, and Biological Sensing Technologies VIII, 80240V (26 May 2011); doi: 10.1117/12.882820
Show Author Affiliations
Hee Kyung Ahn, KAIST (Korea, Republic of)
Hong Jin Kong, KAIST (Korea, Republic of)
Kang Sup Shim, KAIST (Korea, Republic of)


Published in SPIE Proceedings Vol. 8024:
Advanced Environmental, Chemical, and Biological Sensing Technologies VIII
Tuan Vo-Dinh; Robert A. Lieberman; Günter Gauglitz, Editor(s)

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