The Point-Spread-Function (PSF) field characterizes the geometric and diffractive properties of most optical system designs for imaging applications. The conventional method of computing the PSF field is carried out in two steps: first, geometrical computation of the wave aberration function, and then, diffraction evaluation. That method usually applies two approximations: (1) the exit and entrance pupil ray intersection coordinates are equal; and (2) the optical field amplitude distribution does not change between exit and entrance pupil planes. We propose here a variation of the conventional method that allows overcoming these two approximations in axially symmetric optical systems. To show the potentials of the method we applied it to a Cooke triplet. We analyse the influence of the number of traced rays on the measured accuracy of the method. We also evaluate the differences in the PSF estimation accuracy with respect to a method where the two aforementioned approximations were applied.

中文翻译：

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轴对称光学系统中点扩展函数场的计算估计

点扩展函数 (PSF) 场表征了大多数成像应用光学系统设计的几何和衍射特性。计算 PSF 场的传统方法分两步进行：首先是波像差函数的几何计算，然后是衍射评估。该方法通常应用两个近似值：(1) 出射光瞳光线交点坐标相等；(2)光场振幅分布在出射光瞳平面之间没有变化。我们在这里提出了一种传统方法的变体，它可以克服轴对称光学系统中的这两种近似。为了展示该方法的潜力，我们将其应用于库克三元组。我们分析了跟踪射线的数量对方法测量精度的影响。