用蒙特卡罗方法和MATLAB计算冷屏效率  

Computation of Cold Shield Effectiveness with Monte Carlo Method and MATLAB

作　　者：王忆锋[1] 范乃华[1] 毛京湘[1] 

机构地区：[1]昆明物理研究所,云南昆明650223

出　　处：《光电技术应用》2010年第1期26-28,32,共4页Electro-Optic Technology Application

摘　　要：在制冷型红外成像系统中,冷屏具有定义视场角大小、限制杂散光辐射的作用.冷屏有各种孔径形状,但是冷屏效率的计算无解析公式,一般需要用数值方法求解.介绍了用蒙特卡罗方法和MATLAB计算简化的圆形冷屏结构、冷屏效率的一种途径.基于三维空间中的方向数概念,首先利用MATLAB命令生成冷屏区域内的随机点,再赋予该点一组随机方向数,获得一条随机直线方程;根据镜面反射的性质及解析几何公式,追踪该直线在冷屏上的反射光线并判断它是否落入探测器芯片区域,由此可以确定冷屏效率.方法具有编程简单、方便实用等特点.The cold shield defines the angle of view field and limits stray radiation in cooled infrared imaging system. The cold shields have various aperture types but no analytical formula is available for cold shield effec- tiveness, and numerical methods are usually needed for its computation. A Monte Carlo method with MATLAB for computing cold shield effectiveness of a simplified round cold shield structure is presented. It is based on the concept of direction numbers in three dimensional space. First, a random point on cold shield is generated with MATLAB. Then a group of random direction numbers is associated to that point so an equation of a random straight line is formed. After tracing the ray reflected from the cold shield and judging that if it falls into the region of detector chip according to the property of specular reflection and formulae in analytical geometry, the cold shield effectiveness can be determined. It is easy in programming and convenient in operation.

关 键 词：冷屏 冷屏效率 红外成像系统 蒙特卡罗方法 MATLAB 

分 类 号：O435[机械工程—光学工程]