详细介绍了分孔径光学系统初始结构参数确定和光学设计方法。分孔径光学系统是一种偏心系统，可分解为多个同轴子系统的组合，在给出其初级像差表达式的基础上，利用PW法及最小二乘法计算其初始结构参数。优化设计得到了适用于偏振成像的、焦距为40 mm、F数为4.5的和工作波长范围为450~650 nm的四孔径光学系统。该系统采用普通光学玻璃，光学总长为120 mm。镜头的成像性能接近于衍射极限，能够满足应用和指标要求。

Design method of an aperture-divided optical system used for polarization imaging systems is introduced and discussed in detail. Aperture-divided optical system is a decentered optical system composed of several coaxial subsystems. Its primary aberrations are represented based on the primary aberration theory. The initial structure parameters are calculated with the PW method and least square algorithm. A four sub-aperture optical system with effective focal length of 40 mm, F-number of 4.5 and wavelength range from 450 nm to 650 nm is optimized. The system uses an ordinary optical glass with total optical length of 120 mm. Imaging performances of the designed system approache to diffraction-limited and can meet the application requirements of the polarization imaging.