圆形冷屏下红外焦平面探测器光敏元立体角的计算及其成像仿真

给出了圆形冷屏限制下红外焦平面器件任一光敏元立体角的数学模型,该模型由非线性方程组描述,通常,难以求出相应的解析解.以320×256面阵器件为例介绍了一种数值求解方法,即先从面阵中选取若干光敏元作为采样点,用SolidWorks三维实体造型软件求出这些光敏元对应的若干几何参数,再用MATLAB做样条插值计算,求出任一点处光敏元的立体角数值.将这些立体角的相对值投影到0～255的整数值范围,可以得到一张伪灰度图,该图反映了理想情况下面阵器件对均匀面源黑体的成像效果.

Calculation of solid angle of pixels of IRFPA detector under circular cold shield and its imaging simulation

For any pixel of infrared FPA detector, the mathematical model of their solid angle was presented under limitation of circular cold shield. This model could be described with nonlinear equations which were difficult to obtain corresponding analytical solutions in general situation. Taking 320×256 FPA detector as an example, a numerical solution was introduced. Firstly, some pixels were selected as sampling points from FPA detector, several geometric parameters corresponding to these pixels could be obtained with the SolidWorks which was a three dimensional solid modeling software. Secondly, the solid angle of any pixel in the FPA detector could be solved using spline interpolation with MATLAB. Mapping the relative value of solid angle into integer range between 0 and 255, a pseudo gray scale image could be formed, which reflected the imaging effect of the FPA detector in ideal condition when an uniform extended area source blackbody put in front of it.