将光纤传像束应用到色散型成像光谱仪中取代其狭缝, 链接望远系统和光谱仪组成光纤成像光谱仪。 它是二重采样系统, 光谱仪的谱线畸变使光纤束采样像元的像与探测器像元之间产生对准偏差, 从而对第二次采样过程产生影响, 导致调制传递函数(MTF)下降。 从线扩散函数角度出发推导出采样过程光学传递函数, 分析了谱线畸变对系统MTF的影响, 建立了一套评价光纤成像光谱仪MTF的模型。 该模型比狭缝型成像光谱仪MTF计算模型多了一项光纤积分MTF因子和一项由谱线畸变引起的对准偏差MTF因子, 最后用该模型评价了某机载可见近红外波段光纤成像光谱仪MTF。 MTF计算模型的推导和建立方法对计算二重采样系统光学传递函数有参考意义, 能指导光纤成像光谱仪的设计。

Imaging fiber bundles were introduced to dispersion imaging spectrometer and substituted for slit, connecting the telescope and spectrometer to yield the imaging fiber-optic spectrometer. It is a double sampling system, the misalignment between image of optical fiber and detector pixel has arisen because of the spectrum distortion of spectrometer, which affected the second sampling process, and the modulation transfer function (MTF) therefore degraded. Optical transfer function of sampling process was derived from line spread function. The effect of spectrum distortion on system MTF was analyzed, and a model evaluating the MTF of imaging fiber-optic spectrometer was developed. Compared to the computation model of MTF of slit imaging spectrometer, a MTF item of sampling by optical fiber and a MTF item of misalignment arising from spectrum distortion were added in this model. Employing this, the MTF of an airborne imaging fiber-optic spectrometer for visible near infrared band was evaluated. The approach ro deriving and developing the MTF model has a reference signification for the computation of MTF of double sampling system, which can direct the design of imaging fiber-optic spectrometer also.