Piston Error Evaluation and Correction for Multi-aperture Imaging System

Abstract

In this paper, the imaging quality of a three-aperture Golay3 imaging system is studied. The formula of point spread function (PSF) is derived when piston errors exist among each subaperture. The 1951 resolution target is used to analyze the imaging quality under the influence of different piston errors. To evaluate the imaging quality quantificationally, the Tenengrad function based on image gradient definition is employed. The fast steering mirror (FSM) controlled by PZT is used to eliminate the phase error in the optical structure of the Golay3 imaging system. The principle and formula of piston error correction are introduced. Using the Tenengrad function, the relationship between the movement of PZT and the image sharpness is obtained. Through the simulation of piston error correction, the piston error p = λ/2 in the system can be completely corrected when the PZT movement p’ = 0.35λ.