新型航空镜间快门对光学传递函数的影响分析

Abstract

The optical transfer function is the important parameter to evaluate the image quality of optical system. Based on the working property of one new type aviation lens shutter designed for the digital aerial photograph camera, the analysis of influence on the optical transfer function is presented. The lens shutter can change the optical pupil shape of the camera's optical system in the processing of control exposure, which means the point spread function is changed. Thus the optical transfer function is also changed. The relationship between the variety of aperture stop and the optical pupil function is built up by taking the optical system as the spatial frequency filter and adopting the Fourier transfer method and scalar diffraction theory as the theoretical foundation to analysis the influence of the shutter in the working period on the optical transfer function. Through the comparing analysis of the calculation and measurement results, they show that the maximum absolute error is 0.196 and the maximum relative repetitiveness. Furthermore, the design decreases the time ratio occupying whole error is -0.274 for the optical transfer function, which has better accuracy and exposure time for the beginning stage of shutter and the closing stage of shutter. It improves the comprehensive transfer function of system, which provides the theoretical reference for the optimization design of center shutter.