红外与毫米波学报, 2018, 37 (1): 106, 网络出版: 2018-03-14
近红外混叠吸收线光谱解析及线强测量方法研究
Spectral analysis and line strength measurement method of near-infrared overlapped absorption lines
激光吸收光谱 光谱解析 小波降噪 线型拟合 线强 laser absorption spectroscopy spectrum analysis wavelet denoising line profile fitting line strength
摘要
近年来近红外激光吸收光谱检测技术得以飞速发展,其中对吸收线的光谱解析是光谱检测的重要研究内容之一.文章建立了气体激光吸收光谱测量实验平台,重点研究了混叠吸收线光谱检测算法,以6528.8 cm-1附近氨气吸收线为例,开展了特征光谱解析实验与算法研究.结果表明,结合小波降噪方法后,信号均方根误差降低4.45倍,利用多线Voigt线型拟合算法实现混叠吸收线特征光谱解析,线型拟合残差优于±2%.实验获得了氨气在室温不同压力下的特征吸收光谱,并计算得到各条吸收线的线强参数结果.测量线强与Hitran数据库的相对偏差在5.67~8.2%之间,线强计算的不确定度约为4.6%.有效的混叠吸收线光谱解析算法可实现气体线强参数的准确测量,有益于提高氨气浓度反演的准确性.
Abstract
In recent years, near-infrared laser absorption spectroscopy detection technique has developed rapidly, and spectral analysis of absorption lines is one of the important research contents of spectrum detection. The experimental platform for gas laser absorption spectroscopy measurement was established in this study, moreover the experiment of ammonia characteristic spectroscopy analysis at 6528.8 cm-1 and algorithm research were carried out. Experimental results show that the root mean square error of the measured signal reduced 4.45 times after combined with wavelet denoising method, and the fitting residual error of overlapped absorption lines was lower than 2% by using multi-line Voigt line profile fitting algorithm. In the experiment, the ammonia characteristic absorption spectrum of different pressures at room temperature was obtained, and the line strength parameters of each absorption line were also calculated. The relative deviation between the measured results and Hitran database was between 5.67~8.2%,and the uncertainty of calculated line strength was about 4.6%. The accurate measurement of line strength by the effective spectrum analysis algorithm of overlapped absorption lines is in favor for improving the accuracy of ammonia concentration inversion.
贾巍, 何莹, 张玉钧, 刘建国, 刘文清, 王敏, 张润梅. 近红外混叠吸收线光谱解析及线强测量方法研究[J]. 红外与毫米波学报, 2018, 37(1): 106. JIA Wei, HE Ying, ZHANG Yu-Jun, LIU Jian-Guo, LIU Wen-Qing, WANG Min, ZHANG Run-Mei. Spectral analysis and line strength measurement method of near-infrared overlapped absorption lines[J]. Journal of Infrared and Millimeter Waves, 2018, 37(1): 106.