基于散射介质成像理论的微光夜视系统研究

Research of low-light-level night vision system based on imaging through scatter medium theory

描述了一种基于大气散射特性分析的微光夜视系统设计。通过分析大气对光学辐射的散射作用,在理想光电成像系统探测方程的基础上,建立了散射介质成像的探测模型,表明大气散射会严重衰减目标对比度,而目标对比度的传递特性即系统调制传递函数将直接影响观察的作用距离。通过选择应用响应光谱主要集中于0.6μm^1.0μm的三代像增强器,优化设计光学系统的MTF,实现了大气环境下的微光系统作用距离的提高。完成的两种焦距分别为250mm和320mm,采用了三代像增强器的夜视仪.野外试验表明,实现对空目标作用距离最大13.7km^18.3km发现、8.0km^8.1km识别。

A design of the low-light-level（L3） night vision system is described.The design bases on imaging through scatter medium theory.By analyzing the scatter influence of atmosphere to optical radiation,a detecting mathematics model for the imaging through scatter medium is built in virtue of the detecting equation of a perfect photoelectric image system.It is indicated that the target＇s contrast is badly attenuated by the scatterance of atmosphere and the contrast transfer characteristic of the target,viz.the modulation transfer function（MTF）,is direct effect factor to the virtual observation range of the night vision system.A 3rd generation image intensifier is used whose response spectrum is focused in 0.6μm—1.0μm.The MTF of the objective lens of the system is optimized in the lower spatial frequency.The virtual observation range of the night vision system is improved in atmosphere.Two kinds of the L3 image system used 3rd generation tube are developed that have respectively the focus length of 250mm and 320mm.The result is achieved in an outdoor test that a plane target is detected at 13.7km—～18.3km max.and recognized at 8.0km-8.1km max.