滤光片对非色散成像系统获取污染气体柱浓度的影响
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摘要
研究了滤光片对非色散可见成像系统获取污染气体柱浓度的影响。分析了滤光片的中心波长与入射角度之间的关系,发现滤光片的中心波长随入射角度的增大向短波方向移动,当入射角度为40°时,滤光片的中心波长漂移17.4 nm。探讨了不同滤光片对信噪比(SNR)、线性响应及灵敏性的影响。研究结果表明,可通过延长曝光时间或叠加图片增大SNR;半峰全宽为10 nm的滤光片具有较好的灵敏性;0.9以上的线性响应系数表明,半峰全宽为40 nm的滤光片仍满足非色散成像系统解析污染气体柱浓度的理论条件;半峰全宽为10 nm的滤光片的检测下限最优,约为4.475×10~(16) molecule/cm~2,获取污染气体柱浓度的滤光片最佳半峰全宽取值范围为2～40 nm之间。基于半峰全宽为10 nm、中心波长为450 nm的滤光片对某钢铁厂烟囱的烟羽进行了测量,获得了烟羽中NO_2柱浓度的二维空间分布图。
The effect of filter on the column density of polluted gas in the non-dispersive visible imaging system is studied. The relationship between central wavelength and incident angle is analyzed for the filter, and it is found that the central wavelength of the filter shifts toward the short-wave direction with the increase of the incident angle. When the incident angle reaches up to 40°, the center wavelength of the filter has a drift of 17.4 nm. The influences of different filters on the signal to noise ratio(SNR), linear response and sensitivity are also discussed. The research results show that the SNR can be increased by the increase of exposure time or by the image stack. The filter with a full width at half maximum(FWHM) of 10 nm possesses good sensitivity. At the same time, the linear response coefficient above 0.9 indicates that a filter with a FWHM of 40 nm can still satisfy the theoretical condition for resolving the column density of polluted gas in the non-dispersive imaging system. The detection limit for a filter with a FWHM of 10 nm is the best, which is about 4.475×10~(16) molecule/cm~2. The optimal FWHM is between 2 nm and 40 nm for obtaining the column density of polluted gas. Based on the filter with a FWHM of 10 nm and a central wavelength of 450 nm, the two-dimensional spatial distribution map of NO_2 column density is obtained by measuring remotely the smoke plume from the chimneys in one steel plant.
The effect of filter on the column density of polluted gas in the non-dispersive visible imaging system is studied. The relationship between central wavelength and incident angle is analyzed for the filter, and it is found that the central wavelength of the filter shifts toward the short-wave direction with the increase of the incident angle. When the incident angle reaches up to 40°, the center wavelength of the filter has a drift of 17.4 nm. The influences of different filters on the signal to noise ratio(SNR), linear response and sensitivity are also discussed. The research results show that the SNR can be increased by the increase of exposure time or by the image stack. The filter with a full width at half maximum(FWHM) of 10 nm possesses good sensitivity. At the same time, the linear response coefficient above 0.9 indicates that a filter with a FWHM of 40 nm can still satisfy the theoretical condition for resolving the column density of polluted gas in the non-dispersive imaging system. The detection limit for a filter with a FWHM of 10 nm is the best, which is about 4.475×10~(16) molecule/cm~2. The optimal FWHM is between 2 nm and 40 nm for obtaining the column density of polluted gas. Based on the filter with a FWHM of 10 nm and a central wavelength of 450 nm, the two-dimensional spatial distribution map of NO_2 column density is obtained by measuring remotely the smoke plume from the chimneys in one steel plant.
引文
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[9] Mori T, Burton M. The SO2 camera: A simple, fast and cheap method for ground-based imaging of SO2 in volcanic plumes[J]. Geophysical Research Letters, 2006, 33(24): L24804.
[10] Mori T, Burton M. Quantification of the gas mass emitted during single explosions on Stromboli with the SO2 imaging camera[J]. Journal of Volcanology and Geothermal Research, 2009, 188(4): 395-400.
[11] Kern C, Kick F, Lübcke P, et al. Theoretical description of functionality, applications, and limitations of SO2 cameras for the remote sensing of volcanic plumes[J]. Atmospheric Measurement Techniques, 2010, 3(3): 733-749.
[12] Nadeau P A, Palma J L, Waite G P. Linking volcanic tremor, degassing, and eruption dynamics via SO2 imaging[J]. Geophysical Research Letters, 2011, 38(1): 121-133.
[13] Tamburello G, Kantzas E P, McGonigle A J S, et al. UV camera measurements of fumarole field degassing (La Fossa crater, Vulcano Island)[J]. Journal of Volcanology and Geothermal Research, 2011, 199(1/2): 47-52.
[14] Klein A, Lübcke P, Bobrowski N, et al. Plume propagation direction determination with SO2 cameras[J]. Atmospheric Measurement Techniques, 2017, 10(3): 979-987.
[15] Gli? J, Stebel K, Kylling A, et al. Improved optical flow velocity analysis in SO2 camera images of volcanic plumes-implications for emission-rate retrievals investigated at Mt Etna, Italy and Guallatiri, Chile[J]. Atmospheric Measurement Techniques, 2018, 11(2): 781-801.
[16] Dalton M P, Watson I M, Nadeau P A, et al. Assessment of the UV camera sulfur dioxide retrieval for point source plumes[J]. Journal of Volcanology and Geothermal Research, 2009, 188(4): 358-366.
[17] Nisulescu G C, Ionel I, Malan B, et al. Remote SO2 monitoring with UV cameras for stack emissions[J]. Revista de Chimie, 2012, 63(9): 940-944.
[18] Prata A J. Measuring SO2 ship emissions with an ultraviolet imaging camera[J]. Atmospheric Measurement Techniques, 2014, 7(5): 1213-1229.
[2] Liu J, Si F Q, Zhou H J, et al. Estimation of sulfur dioxide emission from power plant using imaging differential optical absorption spectroscopy technique[J]. Acta Optica Sinica, 2015, 35(6): 0630003. 刘进, 司福祺, 周海金, 等. 基于成像差分吸收光谱技术测量电厂SO2排放方法研究[J]. 光学学报, 2015, 35(6): 0630003.
[3] Stevenson J A, Varley N. Fumarole monitoring with a handheld infrared camera: Volcán de Colima, Mexico, 2006-2007[J]. Journal of Volcanology and Geothermal Research, 2008, 177(4): 911-924.
[4] Wilkes T, Pering T, McGonigle A, et al. A low-cost smartphone sensor-based UV camera for volcanic SO2 emission measurements[J]. Remote Sensing, 2017, 9(1): 27.
[5] Dekemper E, Vanhamel J, van Opstal B, et al. The AOTF-based NO2 camera[J]. Atmospheric Measurement Techniques, 2016, 9(12): 6025-6034.
[6] Zhang Y H, Li A, Xie P H, et al. An UV imaging methods applicable to the two-dimensional spatial distribution of pollutant concentration[J]. Spectroscopy and Spectral Analysis, 2018, 38(5): 1476-1480. 张英华, 李昂, 谢品华, 等. 污染气体浓度二维空间分布的紫外成像方法[J]. 光谱学与光谱分析, 2018, 38(5): 1476-1480.
[7] Corradini S, Tirelli C, Gangale G, et al. Theoretical study on volcanic plume SO2 and ash retrievals using ground TIR camera: Sensitivity analysis and retrieval procedure developments[J]. IEEE Transactions on Geoscience and Remote Sensing, 2010, 48(3): 1619-1628.
[8] Osorio M, Casaballe N, Belsterli G, et al. Plume segmentation from UV camera images for SO2 emission rate quantification on cloud days[J]. Remote Sensing, 2017, 9(6): 517.
[9] Mori T, Burton M. The SO2 camera: A simple, fast and cheap method for ground-based imaging of SO2 in volcanic plumes[J]. Geophysical Research Letters, 2006, 33(24): L24804.
[10] Mori T, Burton M. Quantification of the gas mass emitted during single explosions on Stromboli with the SO2 imaging camera[J]. Journal of Volcanology and Geothermal Research, 2009, 188(4): 395-400.
[11] Kern C, Kick F, Lübcke P, et al. Theoretical description of functionality, applications, and limitations of SO2 cameras for the remote sensing of volcanic plumes[J]. Atmospheric Measurement Techniques, 2010, 3(3): 733-749.
[12] Nadeau P A, Palma J L, Waite G P. Linking volcanic tremor, degassing, and eruption dynamics via SO2 imaging[J]. Geophysical Research Letters, 2011, 38(1): 121-133.
[13] Tamburello G, Kantzas E P, McGonigle A J S, et al. UV camera measurements of fumarole field degassing (La Fossa crater, Vulcano Island)[J]. Journal of Volcanology and Geothermal Research, 2011, 199(1/2): 47-52.
[14] Klein A, Lübcke P, Bobrowski N, et al. Plume propagation direction determination with SO2 cameras[J]. Atmospheric Measurement Techniques, 2017, 10(3): 979-987.
[15] Gli? J, Stebel K, Kylling A, et al. Improved optical flow velocity analysis in SO2 camera images of volcanic plumes-implications for emission-rate retrievals investigated at Mt Etna, Italy and Guallatiri, Chile[J]. Atmospheric Measurement Techniques, 2018, 11(2): 781-801.
[16] Dalton M P, Watson I M, Nadeau P A, et al. Assessment of the UV camera sulfur dioxide retrieval for point source plumes[J]. Journal of Volcanology and Geothermal Research, 2009, 188(4): 358-366.
[17] Nisulescu G C, Ionel I, Malan B, et al. Remote SO2 monitoring with UV cameras for stack emissions[J]. Revista de Chimie, 2012, 63(9): 940-944.
[18] Prata A J. Measuring SO2 ship emissions with an ultraviolet imaging camera[J]. Atmospheric Measurement Techniques, 2014, 7(5): 1213-1229.