傅里叶干涉成像光谱技术中的重构方法

Method of reconstruction on Fourier-Transform spectroscopy

在干涉成像光谱仪的光谱复原中,由于系统存在各种误差,若直接对所得干涉图进行傅里叶变换重构,得到的光谱图会产生较大误差甚至错误。介绍了Sagnac型干涉成像光谱仪基本原理,针对上述问题得到一套对采集得到的干涉图进行光谱重构的方法,通过对所采集干涉图进行消趋势项、切趾、相位校正、共轭对称化等步骤的处理,再进行重构,即可有效避免直接重构所带来的误差,使用所研制的原理样机对氦灯等单色光源进行光谱曲线重构实验,得到的光谱强度分布曲线与标称曲线基本吻合,光谱复原精度达到了4nm,具有较好的重构效果。

In the course of spectrum reconstruction of Fourier-Transform spectrometer, there will be large error of the spectrum if the interferogram is transformed directly without any other process, because there is machining error as well as some other errors in the system. According to the theory of Sagnac Fourier-Transform spectrometer, the method which we used to reconstruct the spectrum correctly from the captured interferogram was developed. With the steps of trend term correction, apodisation, phase correction and conjugate symmetrization applied to the interferogram captured and then reconstructed it, the error was avoid. The experiment to reconstruct the spectrum of monochromatic light source such as Helium lamp used in the developed prototype was carried out. The results agree with the nominal spectrum distibutions of the sources with the accuracy of 4 nm.