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光学传递函数是评价光学系统成像质量的重要指标。基于为数字航空摄影相机设计的一种新型航空镜间快门的工作特性,镜间快门在控制曝光过程中改变了相机光学系统的光瞳形状,意味着点扩展函数的改变,从而改变了光学系统的传递函数。将光学系统视为一个空间频率的滤波器,以傅里叶积分变换和光的标量衍射理论为基础,将孔径光阑的变化过程与光瞳函数建立关系,应用二次傅里叶变换法得到光学传递函数,分析快门在工作周期内对光学传递函数的影响。通过对计算结果与测量结果的对比分析可知,传递函数的最大绝对误差为0.196,最大相对误差为-0.274,有较好的准确度和重复性,并且缩小镜间快门开始和关闭阶段所用时间占整个曝光时间的比例,可以提高系统的综合传递函数,为中心快门的优化设计提供理论依据。
Optical transfer function is an important index to evaluate the imaging quality of optical system. Based on the operating characteristics of a new type of aviation mirror shutter designed for digital aerial photography cameras, the inter-mirror shutter alters the pupil shape of the camera’s optical system during controlled exposures, implying a change in the point spread function, thereby altering the optical system Transfer function. The optical system is regarded as a spatial frequency filter. Based on the Fourier integral transform and the scalar diffraction theory of light, the relationship between the aperture aperture and the pupil function is established. The quadratic Fourier transform is used to obtain the optical Transfer function to analyze the influence of the shutter on the optical transfer function during the work cycle. By comparing the calculation results with the measurement results, the maximum absolute error of the transfer function is 0.196 and the maximum relative error is -0.274, which shows good accuracy and repeatability. The time taken to reduce the shutter opening and closing phases The proportion of the entire exposure time, can improve the system’s integrated transfer function, to provide a theoretical basis for the optimal design of the center shutter.