基于光阑优化设计对非制冷红外成像系统内部杂散光的抑制研究

The internal stray light is an imp、ortant factor affecting the performance of uncooled infrared imaging systems. It has existed in many military uncooled infrared imaging systems for a long time, seriously interfering with the weapon equipment’s identification and aiming to the target. At present, there is still a lack of effective solutions for it either in the domestic and foreign documentary records or in the practical application. Our previous studies found that it is an effective solution for stray light suppression to assemble an internal stop with an abnormally-shaped aperture in the uncooled detector window and an external stop with special surface shape out of the window. The solution can meet the requirements of low cost and small size for uncooled infrared imaging systems, and is suitable for all kinds of uncooled infrared imaging systems. Therefore, optimization and design for the aperture shape of internal stop and the surface shape of external stop is the key to suppress stray light in the uncooled infrared imaging systems. The project intends to use superposition method and Monte Carlo method to calculate the stray light energy distribution of internal and external stop. Based on the methods and the idea of mathematical optimization, mathematical model of optimization and design for internal and external stop will be built. Then the internal stray light suppression technology for all kinds of uncooled infrared imaging systems will be mastered, which provides a new idea to solve the problem of the stray light in the uncooled infrared imaging system, and thus the detection and identification accuracy and anti-jamming capability of the whole uncooled infrared weapon systems will be promoted.

内部杂散光是影响非制冷红外系统成像性能的重要因素，它长期存在于很多军用非制冷红外成像系统，严重干扰武器系统对目标的识别瞄准，从国内外文献和实际应用情况来看，目前仍缺有效的解决方法。我们前期研究发现，在非制冷探测器窗口内外分别增设异形开孔的内光阑和特殊表面形状的外光阑，是有效的杂光抑制方式，能满足非制冷系统低成本、小型化要求，有较强的普遍适用性。因此，对内光阑的开孔形状、外光阑的表面形状进行优化设计，是抑制非制冷成像系统内部杂散光的关键。本项目拟分别采用叠加运算法和蒙特卡洛法计算内、外光阑对应的杂散光能量分布状况，在此基础上，利用最优化计算的数学思路，建立优化设计内、外光阑的数学模型，掌握对各类非制冷系统具有普遍适用性的内部杂光抑制技术，为解决非制冷红外成像系统的杂散光问题提供新思路，从而提升整个非制冷红外武器系统的探测与识别精度和抗干扰能力。

内部杂散光是影响非制冷红外系统成像性能的重要因素，它长期存在于很多军用非制冷红外成像系统，严重干扰对目标的识别瞄准，目前缺少有效的解决方法。本项目提出，在非制冷探测器窗口内外分别增设异形开孔的内光阑和特殊表面形状的外光阑，可有效抑制杂散光，满足非制冷系统低成本、小型化要求，并有较强的普遍适用性。因此，开展对内光阑的开孔形状、外光阑的表面形状优化设计的研究。.对于外光阑异形表面散射杂散光的计算，提出了一种新的蒙特卡洛（MC）方法。与传统的MC光线追迹方法相比，利用空间离散和网格递减的方法来代替求解方程组的方法，以寻找光线与外光阑异形表面的交点。结果表明该方法具有较高的计算效率和对不同形状曲面的适用性，计算耗时仅为传统算法的1/6。该算法的建立，不仅能够用于外光阑表面结构的评价和优化计算，其思路也可扩展应用到其它的内部杂散光传输计算。另外，建立了区域法计算杂散光通过内光阑在焦平面上照度分布的模型，为内光阑开孔形状的优化奠定基础。基于内、外光阑对应的焦平面杂散光能量分布状况计算模型，把光阑的优化抽象成数学中的最优化计算，建立了变量模型和目标函数模型，采用区间穷举法作为极值搜寻方法，并完成了优化光阑形状的程序编制。.针对典型的非制冷红外探测器，利用建立的数学方法优化设计外光阑表面形状和内光阑的开孔形状，将其搭配用于非制冷探测器。通过仿真和实物实验，修正了优化光阑的数学模型；并根据对最终设计光阑的仿真和实验结果，验证了内、外光阑对探测器杂散光的抑制作用，进而验证了光阑优化设计方法的正确性与实用性，为削弱非制冷红外成像系统的杂散光提供新思路，对提升整个非制冷红外武器系统的探测与识别精度和抗干扰能力具有重要意义。