氢气拉曼光谱压缩感知方法分析研究

Study on Compressed Sensing Method for Raman Spectroscopic Analysis of Isotope Hydrogen Gas

气体监测与我们的生活息息相关,氢气作为一种理想的研究模型更是受到广泛关注。拉曼光谱作为一种气体分析手段,具有无损非接触等优点。气体拉曼光谱测量存在的一个主要问题是拉曼散射信号弱。在一些特定场景下,需要信号采集时间较短,因此获得的拉曼光谱信噪比低。压缩感知方法作为一种新发展起来的信号处理手段,不仅可以压缩采样,缩短采样时间,而且可以降噪,提高信噪比,以更好地实现原始信号的恢复和重建。该研究以氢气和氘气为测量对象,分别采用洛伦兹函数设计原子构建字典OMP(orthogonal matching pursuit)算法重构和傅里叶变换滤波后多个正交基构建正交基字典OMP重构两种压缩感知方法分析氢同位素气体的拉曼光谱。通过对仿真数据和实际测量数据的处理,比对了两种压缩感知分析与小波软阈值、小波硬阈值和SG(Sawitzky-Golay)滤波处理的谱峰强度效果以及信噪比和均方根误差,证明洛伦兹函数设计原子构建字典OMP算法重构可以用于氢气拉曼光谱降噪。

Gas monitoring is closely related to our lives,and hydrogen as an ideal research model has received widespread attention.Raman spectroscopy has the advantages of non-destructive and non-contact measurements.One of the main problems in Raman measurement for gases is the weak Raman scattering.In some specific scenarios,the signal acquisition time is required to be short,so the obtained Raman spectrum has a low signal-to-noise ratio.As a newly developed signal processing method,the compressed sensing method can compress and sample the signal,shorten the sampling time,and reduce the noise and improve the signal-to-noise ratio to better realize the restoration and reconstruction of the original signal.This study used hydrogen and deuterium mixed gas as the measurement object.Two compressed sensing methods were used to analyze the Raman spectra with different sparse matrices:One of the sparse matrices using the Lorentz function to design atoms of the dictionary of OMP(Orthogonal Matching Pursuit)algorithm,and another sparse matrix using Fourier transform filtering to construct the orthogonal basis dictionary of OMP.Through the processing of simulation data and actual measurement data,we compare the effects of the two methods of compressed sensing analysis with wavelet soft threshold,hard wavelet threshold and SG(Sawitzky-Golay)filter processing,and peak intensity,signal-to-noise ratio,and root mean square error.It is demonstrated that using the Lorentz function to design the dictionary of the OMP algorithm can reduce noise for gas Raman spectra.