小波降噪对TDLAS 干涉抑制的研究

大气与环境光学学报 ›› 2022, Vol. 17 ›› Issue (3): 328-335.

小波降噪对TDLAS 干涉抑制的研究

冯仕凌, 崔琪, 郭心骞, 邱选兵, 郭古青, 和小虎, 李传亮∗

太原科技大学应用科学学院, 山西太原 030024

收稿日期:2020-10-30 修回日期:2022-04-22 出版日期:2022-05-28 发布日期:2022-05-28
通讯作者: E-mail: clli@tyust.edu.cn E-mail:li_chuanliang@126.com
作者简介:冯仕凌 (1993 - ), 山西运城人, 硕士研究生, 主要从事光电探测技术及应用的研究。 E-mail: S20180158@stu.tyust.edu.cn
基金资助:
Supported by National Natural Science Foundation of China (国家自然科学基金, U1810129, 11904252, 52076145）

Optical fringes removal in TDLAS based on wavelet denoising

FENG Shiling, CUI Qi, GUO Xinqian, QIU Xuanbing, GUO Guqing, HE Xiaohu, LI Chuanliang∗

School of Applied Science, Taiyuan University of Science and Technology, Taiyuan 030024, China

Received:2020-10-30 Revised:2022-04-22 Published:2022-05-28 Online:2022-05-28

摘要/Abstract

摘要： 基于多光程吸收池的可调谐半导体激光吸收光谱 (TDLAS) 系统在检测过程中容易出现噪声干扰, 影响着其实际检测性能。针对这种干扰的特征进行分析, 提出利用小波降噪法来改善 TDLAS 系统的探测性能。首先依据理论研究结果选择合适的小波函数和分解层数, 然后通过这种小波对叠加干扰的仿真信号进行滤波, 结果表明这种降噪技术具有良好的去噪效果。最后利用小波降噪技术处理了实验采集的不同浓度气体的直接吸收光谱 (DAS) 和二次谐波信号, 相比于原信号, 降噪后信号的信噪比从 0.4 增加到 259, 系统的检测限也达到 7×10−6, 表明小波降噪方法在气体光谱检测中具有较高的应用价值。

关键词: 可调谐半导体激光吸收光谱, 信号处理, 小波降噪

Abstract: The TDLAS system combined with multi-path absorption cell is prone to interference noise in practical application, which has a very adverse impact on its detection performance. In this work, the causes of this interference are analyzed, and a wavelet denoising method is proposed to improve the detection performance of the system. Firstly, the appropriate wavelet function and decomposition layers are selected according to the theoretical research results, and then the simulation signal with superimposed interference is filtered through this wavelet. The results show that this noise reduction technology has good application performance. Finally, the direct absorption spectrum (DAS) and second harmonic signal of each carbon dioxide concentration collected in the experiment are processed by wavelet denoising technology. Compared with the original signal, the signal-to-noise ratio of the denoised signal is increased from 0.4 to 259, and the detection limit of the system reaches 7×10−6, which indicates that the proposed small wave noise reduction method has high application value in the detection of ambient gases.

Key words: tunable diode laser absorption spectroscopy, signal processing, wavelet denoising

中图分类号:

冯仕凌, 崔琪, 郭心骞, 邱选兵, 郭古青, 和小虎, 李传亮∗. 小波降噪对TDLAS 干涉抑制的研究[J]. 大气与环境光学学报, 2022, 17(3): 328-335.

FENG Shiling, CUI Qi, GUO Xinqian, QIU Xuanbing, GUO Guqing, HE Xiaohu, LI Chuanliang∗. Optical fringes removal in TDLAS based on wavelet denoising[J]. Journal of Atmospheric and Environmental Optics, 2022, 17(3): 328-335.

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