空间外差光谱仪系统级平场校正方法研究

空间外差光谱仪单独进行面阵探测器校正无法满足系统级响应非一致性校正需求，传统均匀光源照射和列平场等方法对空间外差光谱仪并不适用。首先简要阐述了空间外差光谱仪传统挡光臂平场方法原理，指出传统挡光臂平场方法存在测量单臂数据在光栅胶合后与实际干涉数据不匹配的问题，不匹配形式包括像元级、亚像元级平移和旋转。针对实验室现有实验装置分析了平场系数配准精度的影响，通过分析单臂数据不同偏移量与光谱偏差之间的定量关系，得出本实验装置平场系数的配准精度需要优于0.1像元。根据配准需求，采用对数—极坐标变换求出旋转角度和相位相关方法进行像元级平移量计算，通过基于矩阵乘法的DFT实现亚像元级平移量的估算。最后总结了系统级平场方法的流程，利用实验室装置对空间外差光谱仪系统级平场方法进行了验证，通过对光栅位置的微量调整模拟实际胶合后干涉仪整体状态，对模拟胶合后数据采用平场校正流程与单臂数据完全匹配下校正后的光谱对比显示，二者之间光谱平均偏差为0.6%，与不校正时4.1%的光谱偏差相比，校正后光谱复原精度大大提高，为后续进一步数据处理奠定基础。

The Research of Flatfielding Correction Method for Spatial Heterodyne Spectrometer at Systematic Level

It can't satisfy the requirement of correction for response non-uniformity at systematic levelif only if the array detector for spatial heterodyne spectrometer i s corrected .Traditional methods,such as irradiation with uniform source and column-flat-fielding,are not suitable for spatial heterodyne spectrometer .T he article expounds convection arm-blocking method for spatial heterodyne spectrometer briefly at first .This method leads to kinds of mismatches including pixel and sub-pixel level shift and rotation in a single arm data after gluing gratings .The effect of registration accuracy of flatfielding coefficients has been analyzed for the experimental breadboard .The result shows that the registratio n accuracy of flatfielding coefficients needs to be better than 01 pixel for t he breadboard .The shift at pixel level is calculated by solving the rotational degree by using logarithm-polar coordinate and phase correlation method for the requirement of registration .The shift at sub-pixel level is estimated with DFT based on matrix multiplication .The flow path of flatfielding method at systematic level is concluded .The integral condition of interferometer after actual gluing is modulated by adjusting the positions of gratings slightly .The flatfielding flow path is applied to the data acquired from the modulated interferometer after gluing .Then,the result is compared with the spectrum after the correction with totally matched signal arm data .The final result shows that the spectral deviation is 0.6％ between the two spectra compared with the spectral deviation of 4.1％ without correction .The accuracy of recovered spectrum after correction has been improved markedly .This can be the foundation for the follow data processing .