任意冷屏对应的像面能量分布状况的计算

红外光学系统中存在许多冷屏效率远低于100%的情况,对于这类系统,冷屏对杂散光的抑制能力可以用像面接收的信号能量和杂散能量分布状况来反映,而接收辐射能的多少又可用冷屏和光瞳相对于像面的立体角大小表征。文中首先采用逆向追迹光线的统计方法,提出了准确计算立体角的新思路;然后基于此方法设计了程序,计算任意形状的冷屏对应的像面信号能量和杂散能量的分布情况;最后用所编程序对某典型热像仪进行实例分析,验证了程序的准确性和适用性。该程序计算所得的参数可对冷屏的优劣性进行评价,也可用作冷屏优化的目标参数,为冷屏的优化设计做了关键的铺垫。

Calculation of energy distribution in image plane for all shapes of cold shields

The efficiency of cold shield is probably much lower than 100% in many infrared optical systems.For these systems,cold shield′s ability of suppressing stray light can be indicated by the energy distribution in image plane from target and stray light,which can be described by the solid angles bounded by cold shield or stop for image plane.In this article,a creative idea of using the statistical method of converse ray tracing to accurately calculate the solid angles was proposed.Based on this method,a program was compiled to compute the signal and stray energy distribution in image plane for all shapes of cold shields.Moreover,a typical thermal imager was chosen as an instance to be analyzed by the program,and finally the program was proved to be applicable.The parameters calculated by this program can evaluate the quality of cold shields and be used as target parameters to optimize cold shields,which can establish a significant basis for the optimization and design of cold shields.