光学测量系统信噪比优化方法研究  

Research on Optimization Method of Signal-to-Noise Ratio in Optical Measurement Systems

作　　者：李卓然 李雨霄 蒋依芹 刘子龙[1] LI Zhuoran;LI Yuxiao;JIANG Yiqin;LIU Zilong(National Institute of Metrology,Beijing 100029,China;China Electric Power Research Institute,Beijing 100192,China)

机构地区：[1]中国计量科学研究院,北京100029 [2]中国电力科学研究院有限公司,北京100192

出　　处：《计量科学与技术》2022年第2期50-54,共5页Metrology Science and Technology

基　　金：国家自然科学基金面上项目(61875180);国家重点研发计划(2017YFF0205103)。

摘　　要：在光学测量中常常受低信噪比问题的影响,导致测量结果的不确定度增大。近红外波段双向反射分布函数(BRDF)的测量由于红外信号强度偏弱,易受环境干扰,面临的低信噪比问题尤其突出。光学测量系统的信噪比问题一般产生自探测系统,对于红外测量系统来说,经常使用斩波器、锁相放大器进行弱信号测量,但同时也引入了噪声问题。因此,本文针对近红外波段BRDF测量信噪比问题,从探测器、斩波器、锁相放大器三部分着手,分析噪声来源并针对性地提出抑制方法与优化措施,以提升信号信噪比。优化后的测量系统较优化前抗噪声能力提高,可重复性由优化前的2.1%提升到1.6%。Optical measurement are often affected by low signal-to-noise ratios(SNR),resulting in larger measurement uncertainty.Measurement of the bidirectional reflectance distribution function(BRDF)in the near-infrared is particularly vulnerable to environmental interference due to weak infrared signals.The signal-to-noise ratio problem of optical measurement systems generally arises from detection systems.For infrared measurement systems,choppers and lock-in amplifiers are often used for weak signal measurement,but noise problems are also introduced at the same time.Therefore,this article focuses on the SNR of BRDF measurement in the near-infrared,aiming at the detector,chopper and lock-in amplifier,analyzing the source of noise,and proposing suppression methods and optimization measures to improve the signal-to-noise ratio.The optimized measurement system has improved anti-noise ability compared with that before optimization,and the repeatability has been improved from 2.1%to 1.6%.

关 键 词：信噪比 噪声抑制 锁相放大器 斩波器 双向反射分布函数 近红外 

分 类 号：TH74[机械工程—光学工程]