傅里叶变换光谱相位特性及处理方法研究  

Phase Characterizing and Processing in Fourier Transform Spectroscopy

作　　者：刘加庆 李志增 李婧[3] 刘雷 刘磊 郭洪龙 王建国 LIU Jia-qing;LI Zhi-zeng;LI Jing;LIU Lei;LIU Lei;GUO Hong-long;WANG Jian-guo(China Electronics Technology Instruments Co.,Ltd.,Qingdao 266555,China;Science and Technology on Electronic Test&Measurement Laboratory,Qingdao 266555,China;College of Electronics and Information Engineering,Shandong University of Science and Technology,Qingdao 266590,China;The 41st Research Institute of China Electronics Technology Group Corporation,Qingdao 266555,China)

机构地区：[1]中电科仪器仪表有限公司,山东青岛266555 [2]电子测试技术重点实验室,山东青岛266555 [3]山东科技大学电子信息工程学院,山东青岛266590 [4]中国电子科技集团公司第四十一研究所,山东青岛266555

出　　处：《光谱学与光谱分析》2020年第11期3328-3335,共8页Spectroscopy and Spectral Analysis

基　　金：国家重点研发计划项目(2017YFF0106900);国家自然科学基金项目(61727821);预研基金项目(JZX7Y2019XXXXX01);电子测试技术重点实验室稳定经费支持计划项目(KWD03012003)资助。

摘　　要：相位校正是傅里叶光谱仪的关键处理步骤,校正精度受仪器特性和不受控环境因素等的影响,如干涉仪温度变化、机械振动等。针对干扰因素引入的相位不确定性及由此带来的校正难题,在对傅里叶光谱仪相位特性进行量化分析的基础上,将测量光谱相位分解为干涉仪温度相关的仪器相位和零光程点采样误差相关的线性相位。其中,仪器相位主要由傅里叶光谱仪自身特性决定,受到干涉仪温度波动影响,干涉仪温度稳定时的仪器相位大致为常数;零光程差点采样误差是线性相位的主要来源,并且每次测量时的采样零光程差点位置都有所不同,这会导致每个获取干涉数据的光谱相位不同。假设干涉仪稳定在温度限内的仪器相位大致为常数,就可将相位处理简化为对线性相位的校正,而包含仪器相位的剩余相位则可在后续的辐射定标过程中予以剔除。相位处理的具体流程如下,获取反演光谱相位数据后,考虑仪器相位的温度相关性,首先采用最小二乘拟合方法提取线性相位项,然后基于提取的线性相位对干涉数据进行对称化处理,对称化处理后的干涉数据相位足够稳定,允许通过光谱均值降低振动等物理效应的干扰,最后在辐射定标过程中,使用复数辐射定标流程,并取定标结果实部作为目标场景的标定光谱辐射数据,即可移除大部分仪器相位,从而完成了相位校正。实验验证环节,首先采用最小拟合方法得到并移除测量光谱的线性相位项后,分析了不同阶次拟合多项式对仪器相位提取精度的影响,结果表明, 5次多项式即可满足需求,此时的均方误差为0.13 rad,更高阶次不会继续改善提取精度。然后基于5次多项式,获取了干涉仪温度为283, 290和300 K时的仪器相位。测量光谱数据移除线性相位和仪器相位后,残余相位误差为幅值在零点处分布的随机噪声,结果表明仪器相位具有Phase correction is a critical procedure for Fourier transform spectrometers(FTS),whose accuracy can be jeopardized from instrument properties and many uncontrollable environmental conditions,such as significant temperature change of interferometer,mechanical disturbances.Nevertheless,a generally applicable phase correction method seems not available,since current research result in limitations of the standard methods and propose solutions tailored to specific instruments.Considering of phase uncertainly and the challenge of phase determination,the phase property of FTS is characterization and analysis,then to resolve the FTS phase into an instrumental phase that is dependent on the interferometer temperature and a linear phase component that accounts for the discrepancy between the actual interferogram zero optical path difference(ZOPD)and the sampled one.The instrumental phase is mostly an instrumental characteristic that can be identified along with the other calibration parameters,the instrumental phase is strongly affected by interferometer temperature fluctuation,the instrumental phase is constant with interferometer temperature changes within threshold;While linear phase is main attributable to the offset between the digitized ZOPD and the real ZOPD,but also a mainly component of FTS phase.According to the principle of FTS,ZOPD sample errors can change abruptly from one interferogram to another;as a result,each spectrum has a different linear phase with respect to the wavenumber.So the phase processing can be simplification as a linear phase correction,residual phase,including the instrumental phase was removed in radiometric calibration later.This work considers the temperature properties of instrument phase,the implemented method is based on the identification of linear phase by least-squares approach,with interferogram symmetrization,residuals phase of measured data is stabilization to permit spectra averaging,so the artifacts due to vibrations are removed,the last step is complex radiometric calibratio

关 键 词：红外傅里叶光谱仪 相位处理 仪器相位 复数辐射定标 

分 类 号：O433.1[机械工程—光学工程]