针对超光谱遥感中,传统定标光源和目标光源光谱精细结构不匹配、精确度量困难,影响定标精度的难题,提出了一种基于数字微镜器件和光谱仪结构的新型光谱可调光源,并设计了该光源的光学系统。详细描述了这种光源系统的工作原理,确定了光学系统的设计方案,计算了系统的结构参数,并说明了具体的设计过程。设计结果表明:在0.4~1.0μm的设计波段上,光学系统整体性能接近衍射极限,各波长点列图RMS半径小于3.5μm,各波长MTFs在37 lp/mm空间频率处都达到0.8左右,满足设计要求。这种新型的光谱可调光源,有望提高目标光谱精细结构模拟的准确度,可利用基于标准探测器的方法进行精确度量,有利于降低超光谱遥感仪的定标不确定度。
The fine structures of traditional calibration sources and target spectra may have differences, which could hinder the calibration accuracy of hyperspectral remote sensors. Furthermore, traditional sources are difficult to be measured accurately. To solve such problems, a novel spectrally tunable source based on digital micromirror device (DMD) and spectroradiometer structure was introduced. The optical system of the new source was designed. The principles of the system, structural parameter calculation of the system and the process of optical design were described in detail. The results indicate that the optical system′s performances are near-diffractive-limit in the whole band from 0.4μm to 1.0μm. The RMS spot radii are less than 3.5μm and the MTFs at 37 lp/mm are near 0.8 for all the design wavelengths, which meet the requirements of the source.The novel source is promising to improve the imitation accuracy of target spectra, and it could also be measured accurately by detector-based calibration method. With these features, the new source is helpful to reduce the calibration uncertainties of remote sensors.