离轴积分腔输出光谱气体传感降噪技术  

Denoising Technique in Gas Sensing Based on Off-Axis Integrated Cavity Output Spectroscopy

作　　者：张海鹏[1,2] 郑凯元 李俊豪 刘梓迪 李秀英 郑传涛[1,2] 王一丁 Zhang Haipeng;Zheng Kaiyuan;Li Junhao;Liu Zidi;Li Xiuying;Zheng Chuantao;Wang Yiding(State Key Laboratory of Integrated Optoelectronics,College of Electronic Science&Engineering,Jilin University,Changchun,Jilin 130012,China;Jilin Provincial Engineering Research Center of Infrared Gas Sensing Technique,Changchun,Jilin 130012,China)

机构地区：[1]吉林大学集成光电子学国家重点联合实验室,电子科学与工程学院,吉林长春130012 [2]吉林省红外气体传感技术工程研究中心,吉林长春130012

出　　处：《光学学报》2021年第24期286-293,共8页Acta Optica Sinica

基　　金：国家重点研发计划(2017YFB0405300);国家自然科学基金(61627823,61775079,61960206004);吉林省科技发展计划(20180201046GX,20190101016JH,20200401059GX)。

摘　　要：为了有效抑制离轴积分腔输出光谱气体传感中存在的系统及腔模噪声并提高信噪比和气体检测灵敏度,在传统经验模态分解(EMD)方法的基础上,提出了一种改进型的EMD滤波算法。在对含噪信号进行分层分解的过程中,结合Savitzky-Golay(SG)滤波算法和互相关运算,利用滤波信号与互相关系数来得到重构滤波信号。利用甲烷气体样品开展的仿真和实验结果表明,采用EMD-SG滤波方法能显著提高信噪比,降低气体检测下限。与传统的小波去噪、卡尔曼滤波相比,EMD-SG滤波算法在处理系统噪声中的高斯白噪声成分和非线性、非平稳的随机噪声成分上具有明显的优势,实现了较好的滤波效果。经EMD-SG滤波算法处理后,吸收信号的信噪比提高了1.9倍,系统的检测下限由8.7×10^(-6)下降到4.6×10^(-6)。所提出的基于离轴积分腔输出光谱技术的EMD-SG滤波算法具有较高的信噪比和较好的去噪效果,有效提升了系统的检测性能,为研制低噪声离轴积分腔气体传感器并将其用于大气环境监测提供了方法和依据。To effectively suppress the system and cavity mode noises in gas sensing based on off-axis integrated cavity output spectroscopy and therefore improve the signal-to-noise ratio(SNR)and gas detection sensitivity,this paper proposes an improved empirical mode decomposition(EMD)filtering algorithm on the basis of the traditional EMD method.In the process of hierarchically decomposing noisy signals,the Savitzky-Golay(SG)filtering algorithm and cross-correlation operation are combined,and a reconstructed filtering signal is obtained by using the filtering signals and correlation coefficients.Simulation and experimental results of methane gas samples show that the EMD-SG filtering method can significantly improve the SNR and reduce the lower limit of gas detection.In addition,compared with traditional wavelet-denoising and Kalman filtering,the EMD-SG filtering algorithm has obvious advantages in processing the Gaussian white noise and the non-linear and non-stationary random noise in the system noise and achieves a better filtering effect.After treatment with the EMD-SG filtering algorithm,the SNR of the absorption signal is increased by 1.9 times,and the lower limit of the detection is reduced from 8.7×10^(-6)to 4.6×10^(-6).The proposed EMD-SG filtering algorithm based on off-axis integrated cavity output spectroscopy has a high SNR and favorable denoising effect and can effectively improve the detection performance of the system.It provides a new method and a basis for developing low-noise gas sensors based on the off-axis integrated cavity to monitor the atmospheric environment.

关 键 词：光谱学 离轴腔增强吸收光谱技术 经验模态分解 Savitzky-Golay滤波 信噪比 

分 类 号：O433.1[机械工程—光学工程]