小波去噪在激光气体遥测系统中的应用  

The application of wavelet de-noising in laser gas remote system

作　　者：任红军 郭东歌 陈海永 陆漫 贾林涛 郑国锋 REN Hongjun;GUO Dongge;CHEN Haiyong;LU Man;JIA Lintao;ZHENG Guofeng(Hanwei Technology Group Co.,Ltd.,Zhengzhou 450001,China)

机构地区：[1]汉威科技集团股份有限公司,郑州450001

出　　处：《自动化与仪器仪表》2021年第7期195-199,共5页Automation & Instrumentation

摘　　要：为了进一步提高激光气体遥测系统的信噪比,降低其最小检测限。基于可调谐激光吸收光谱(TDLAS)技术,在激光气体遥测系统中采用小波变换,对其检测到的二次谐波进行matlab小波去噪仿真实验,并进行气体模拟测试对比。结果表明:使用第二代提升的小波函数相对于传统小波函数的消噪效果好,曲线光滑,有用信息保留度高。应用小波去噪算法后,激光气体遥测系统的信噪比提高为原来的1.93倍,对甲烷气体的最小检测限由4.95μmol/mol·m提升到2.56μmol/mol·m,测量误差由5.5%降低为2.7%,实用性好。In order to improve the signal noise ratio(SNR) of the laser gas remote system, and reduce its minimum detection limit.Based on the tunable laser absorption spectroscopy, a wavelet de-noising simulation experiment is used in the laser gas remote system, and matlab wavelet de-noising simulation test is carried out for the second harmonic detected by the system, and then has carried on the simulation test.The experimental results show that the de-noising effect of the second enhancement wavelet function is better than the traditional wavelet functions, the signal is smooth, and the useful signal is retained better.Applying the wavelet de-noising algorithm, the minimum detection limit of the laser gas remote system is increased from 4.95 μmol/mol·m to 2.56 μmol/mol·m, the measurement error is reduced from 5.5% to 2.7%,and the practicability is well.

关 键 词：激光 遥测 TDLAS 小波变换 第二代小波变换 阈值去噪 

分 类 号：TP29[自动化与计算机技术—检测技术与自动化装置] TN21[自动化与计算机技术—控制科学与工程]