一种过零单边干涉图加权切趾函数对太阳观测中傅里叶变换光谱的影响分析

Analysis of weighted apodization function for zero-crossing single sided interferogram on Fourier transform spectrum in solar observation

傅里叶变换光谱仪(FTS)因其出色的光谱分辨率而广泛用于太阳活动的观测。在使用过零单边干涉图进行光谱复原时,可能会出现频率泄漏、旁瓣效应以及对零光程差附近的采样数据重复利用,从而导致光谱线的平滑和畸变等问题。为了获得更准确的太阳光谱数据,必须对过零单边干涉图进行加权和切趾操作。对此,文章采用了一种奇次多项式非对称加权切趾函数来处理过零单边干涉图,并探讨了使用不同的切趾函数构建非对称加权切趾函数进行光谱恢复的效果。模拟数据实验的结果表明采用奇次多项式非对称加权切趾函数可以有效地恢复光谱。此外,与Griffiths、相里斌以及SP.Davis提出的加权切趾方法相比,文章中提出的方法表现出较小的误差。最后,将所提出的方法应用于Bruker IFS-125HR FTS采集的干涉图数据,与其他切趾方法相比,使用文中提出的方法可以有效地恢复光谱。

Fourier Transform Spectrometer(FTS)has been extensively utlized in solar activity observation because of its ultra-high spectral resolution.During the process of spectral reconstruction using zero-crossing single sided interferogram,spectral are subject to frequency leakage,side lobes effects,and reuse of sampled data near the zero optical path difference resulting in spectral smoothing and distortion.In order to obtain more accurate solar spectra,it is necessary to apply weighted apodization operations to the zero-crossing single sided interferogram.An odd polynomial asymmetric weighted apodization function is utilized to carry out weighted and apodization operations on the zero-crossing single-sided interferogram.An investigation is conducted to assess the impact of employing diverse apodization functions in the construction of an asymmetric weighted apodization function for spectral reconstruction purposes.The simulated experimental results demonstrate that the use of odd polynomial asymmetric weighted apodization function effectively facilitates spectral recovery.Additionally,when compared with the weighted apodization methods proposed by Griffiths,Xiang Libin,and Sumner P.Davis,the method proposed exhibits a smaller error.Finally,the proposed method is further applied to the interferogram obtained from the Bruker IFS-125HR.Compared to other apodization methods,the use of the method proposed in this paper yields superior results in solar spectral recovery.