大孔径静态干涉成像光谱仪获取图谱数据立方体的过程包含干涉仪调制、 探测器矩形函数卷积采样和光谱反演, 其光谱信噪比评估模型复杂。 从光谱能量调制、 采样、 反演的完整传输过程入手, 根据探测器矩形卷积采样原理, 采用离散傅里叶变换取实部的光谱反演方法, 进行信号与噪声的理论推导, 建立了大孔径静态干涉成像光谱仪光谱信噪比评估模型。 考虑了与波数相关的光学系统透过率、 干涉仪分束面效率、 探测器量子效率等仪器设计参数和主要电路噪声参数, 进行了光谱信噪比仿真计算。 利用LASIS仪器进行了光谱信噪比实验测试, 测试结果与模型仿真计算结果平均偏差为358%, 单谱段信噪比趋势基本吻合, 验证了评估模型的正确性。 评估模型中包含了典型LASIS成像光谱仪由输入光谱辐射到输出光谱数据的各项主要技术环节, 在信噪比计算公式中带入干涉仪分束面干涉效率、 探测器矩形采样方式等因素对仪器光谱信噪比的影响算子, 并利用实际仪器进行了实验验证, 对提高LASIS成像光谱仪工程设计水平具有指导意义。

The process of acquiring hyperspectral data cube of a Large Aperture Static Imaging Spectrometer (LASIS) includes several vital and essential steps, such as interferometer modulation, rectangular convolution sampling by pixels of detector and spectra retrieving. In this process, how to precisely evaluate the Signal-Noise Ratio (SNR) of spectra and how to wholly establish a related evaluation model were both generally very complicated. After a full consideration of the transmission process, utilizing the theory of rectangular convolution sampling and the spectral retrieving method regarding the computation of real part of the discrete Fourier transform of interferogram, formulas of both spectral signal and spectral noise were deduced theoretically, and then a evaluation model regarding the spectral SNR of LASIS was established. By using this model and other design factors of LASIS involving the wavenumber related optical transmittance, the interferometer beam splitter efficiency, the detector quantum efficiency and the main circuit noise, a simulation of spectral SNR was implemented. The simulation result was compared with the measurement result of the SNR of a LASIS instrument. The SNR lines and trends of the two match each other basically in single spectral band. The average deviation between them is proved to be 358%. This comparison result demonstrates the feasibility and effectiveness of the evaluation model. This SNR evaluation model consisting of the main technical aspects of typical LASIS instrument from the input spectral radiation to the output spectrum data is possible to be applied widely in practical design and implement of LASIS, as well as may provide valuable reference on SNR calculation and evaluation for other imaging spectrometers.