星载超光谱成像仪杂散光及其测量

Stray Light of Space-Borne Hyperspectral Imager and Its Measurement

超光谱成像仪比一般光谱仪器具有更多的光谱通道和更高的光谱分辨率,而杂散光是影响超光谱成像仪光谱测量精度的重要因素之一,当前光谱仪器的杂散光测量方法尚不能满足超光谱成像仪杂散光检测的需要。作者探讨了此类成像光谱仪杂散光的定义、来源和危害,论述了使用杂散光影响因子di,j描述光谱仪杂散光的可行性和优越性,并给出了杂散光受扰系数fi(λ)和杂散光干扰系数Fi(λ)的定义、物理意义和工程应用价值。最后,介绍了使用窄带滤光片测量星载超光谱成像仪杂散光的测量系统组成、测量步骤和测量结果。结果表明:杂散光影响因子di,j能正确表示光谱仪的杂散光特性,与光源、滤光片、探测器等测量条件无关,而测量效率比谱杂散光系数法至少提高1倍,满足星载超光谱成像仪杂散光测量的工程需要。

Hyperspectral imager has more spectral channels and higher spectral resolution compared to normal spectral instrument.Stray light is one of the important reasons affecting the spectral accuracy of the hyperspectral imager,but the current stray light measurements can＇t meet the need.Definition,sources and harmfulness of stray light are described in the present paper.The feasibility and superiority of the stray light factor di,j,used to describe the stray light characteristics of the spectral instruments,is investigated thoroughly,where the definition,physical significance and value of engineering application of stray light interference factor fi（λ） and stray light disturbance factor Fi（λ） are given.Finally,the system components,measurement procedure and measurement results of the stray light measurement system,using narrow-band filter,are introduced. Results show that the stray light factor di,j meets the need of the stray light measurement because it can indicate the stray light characteristics of the spectral instruments without relationship to the light source,filter,detector and other measurement conditions,and the measurement efficiency is increased at least one-fold than the spectral stray light factors method.