简易光学系统因系统结构简单而存在严重像差, 导致所成图像出现模糊、失真等问题.对简易光学系统的成像特性进行分析, 在已知光学系统焦距和光瞳孔径的条件下, 建立含有像差的点扩散函数模型和图像复原模型, 根据焦面和离焦面图像以及精确的离焦量, 无需点扩散函数的先验信息, 采用相位差异法对简易光学系统所成图像进行重构.实验结果表明：单透镜、双透镜和三透镜系统复原图像质量评价指标提升率分别达到24.96%、24.80%和42.04%, 重构后图像质量均有明显提升.

There are some problems in the simple optical system, such as blurring and distortion of the image due to the serious aberration. The imaging characteristics of the simple optical system are analyzed. A point spread function model with aberration and an image restoration model are established with the prior knowledge that the focal length and pupil aperture of the optical system are known. Only the focal plane and defocus surface images and the precise defocus amount are required, the image obtained by the simple optical system is reconstructed by the phase diversity method without the prior information of the point spread function. The experimental results show that the image quality evaluation index improvement rates of single lens, double lens and three lens system are 24.96%, 24.80% and 42.04%, respectively, and the restored image quality has been improved obviously.