弹光调制干涉图的预处理及相位校正方法

弹光调制傅里叶变换干涉信号是高速、连续非线性变化。为了实现等时间采样干涉信号的准确光谱重建，有必要对弹光调制干涉信号的预处理技术和相位校正方法进行研究。为了从连续的干涉数据中获取一幅完整的干涉图，文中利用干涉图零光程差点的幅值最大特性，获取一幅完整的干涉图。同时，为了克服干涉图的非对称性，提出将改进的Mertz相位校正方法与非均匀快速傅里叶变换算法（NUFFT）相结合，提高重建光谱的速度和准确度。在实验中，通过仿真产生300 K红外黑体的非对称弹光调制干涉图，采用该数据处理方法提高了重建光谱的精度，并以大气窗口为被测对象，比较准确地重建了大气光谱曲线，实现了气体成分的定性分析。

Method of preprocessing and phase correction for photo-elastic modulated interferograms

Interferograms in the photo-elastic modulator Fourier transform spectrometers(PEM-FTS)has high modulation frequency, and its modulated optical path difference is continuous nonlinear. In order to improve the accuracy and stability of the rebuilt spectrums whose interferograms is sampled by the equal time intervals, it is necessary to study the technology of pretreatment and phase correction of photo-elastic modulated interferograms. In the paper, the characteristic that the amplitude of the zero optical path difference was maximum in a interferogram were used to derive these data of a interferogram. Simultaneously, the method which combined the improved Mertz method and the accelerated nonuniform fast Fourier transform algorithm (NUFFT) was put forward to resolve the asymmetric and to improve the velocity and precision of the rebuilt spectrum. In the experiment, the asymmetrical photo-elastic modulated interferograms of 300 K infared blackbody were generated by simulation, the data processing algorithm was applied to enhance the accuracy of the rebuild spectrum, and the atmosphere spectral curve was rebuilt and gas components were qualitative analyzed with the atmosphere window as the measured object.