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Proceedings Paper

Gas imaging detectivity model combining leakage spot size and range
Author(s): Jiakun Li; Lingxue Wang; Meirong Wang; Yue Gao; Weiqi Jin
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Paper Abstract

As to visualize the leaking gas cloud which is not visible to the naked eyes, three categories of techniques have emerged, Backscatter Absorption Gas Imaging, Passive Thermal Imaging, and Imaging Spectrometer. Among these systems, Signal to Noise Ratio (SNR) is generally used to deduce gas leakage detection limit and leads to several performance evaluation parameters, such as Noise-Equivalent Spectral Radiance and Noise-Equivalent Concentration-Path Length. However, in most cases, measuring the SNR accurately is not accessible and usually needs auxiliary instruments. Therefore, we focus on researching a gas leakage detection model according to the general parameter of a thermal imager, Noise Equivalent Temperature Difference (NETD). Firstly, the Gas Equivalent Blackbody Temperature Difference (GEBTD) is obtained by calculating the attenuated radiation of the On-plume path and that of the Off-plume path respectively. A simplified form of GEBTD was derived by our previous paper, assuming that the work range was short and the affection of atmospheric transmission was omitted. But in this paper, more factors are considered to establish a more realistic and accurate detectivity model. The radiation of the gas cloud and the attenuation of the atmosphere are taken into account as well as the size of the leakage spot which inevitably affects the concentration path length. Secondly, the NETD and the GEBTD are compared to determine the detection capability. At last, an experiment is designed to verify the accuracy and reliability of this model on the basis of the gas cloud concentration cone distribution model.

Paper Details

Date Published: 18 May 2012
PDF: 12 pages
Proc. SPIE 8354, Thermosense: Thermal Infrared Applications XXXIV, 835415 (18 May 2012); doi: 10.1117/12.920664
Show Author Affiliations
Jiakun Li, Beijing Institute of Technology (China)
Lingxue Wang, Beijing Institute of Technology (China)
Meirong Wang, Beijing Institute of Technology (China)
Yue Gao, Beijing Institute of Technology (China)
Weiqi Jin, Beijing Institute of Technology (China)


Published in SPIE Proceedings Vol. 8354:
Thermosense: Thermal Infrared Applications XXXIV
Douglas Burleigh; Gregory R. Stockton, Editor(s)

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