Liu Yue, Zhao Yong-Chao, Geng Xiu-Rui, Tang Hai-Rong, Ding Chi-Biao
Institute of Electronics, Chinese Academy of Sciences, Beijing 100080, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Jul;29(7):1809-12.
Fourier transform spectrometer is an important instrument in the remote sensing applications. There are phase error problems in the Fourier transform spectrometer signal processing procedure. In the present paper, the cause of phase error of Fourier transform spectrometers is shown firstly. It is mainly because of inaccuracy of sampling. Then the nonlinearity of phase error is analyzed. It is suggested that it is because that the interferogram is of finite length and the interferogram is discrete that this nonlinearity exists. The authors studied this problem with a new method. The nonlinearity is shown by rigorous derivation and the authors draw the conclusion by reasoning. Then through the nonlinearity of phase error, the authors have a discussion on the possible error in the Mertz phase correcting method. The possible error lies in the phase interpolation procedure, a part of Mertz method. A method consisting of zero adding and transforming is given to reduce this error. The methods are compared and illustrated by an experiment which uses simulated interferogram from standard spectrum library. The experiment demonstrates that the method of zero adding and transforming can reduce the phase error of phase interpolation and improve the problem of rapid phase change under some circumstances, which can help get better spectrum.
傅里叶变换光谱仪是遥感应用中的一种重要仪器。在傅里叶变换光谱仪的信号处理过程中存在相位误差问题。本文首先阐述了傅里叶变换光谱仪相位误差产生的原因，主要是采样不准确。接着分析了相位误差的非线性，认为这种非线性的存在是由于干涉图长度有限且干涉图是离散的。作者用一种新方法研究了这个问题，通过严格推导展示了非线性，并经推理得出结论。然后通过相位误差的非线性，作者对默茨相位校正方法中可能存在的误差进行了讨论，可能的误差存在于默茨方法的一部分——相位插值过程中。给出了一种由补零和变换组成的方法来减少这种误差。通过使用标准光谱库中的模拟干涉图进行实验对这些方法进行了比较和说明。实验表明，补零和变换方法可以减少相位插值中的相位误差，并在某些情况下改善快速相位变化的问题，有助于获得更好的光谱。
