Piston error calibration of zonal reconstruction for a segmented wavefront in lateral shearing interferometry

In a segmented wavefront, the piston error of each region has an influence on the continuity and accuracy of the zonal reconstruction. Accordingly, this paper presents a method to calibrate the piston error and improve reconstruction accuracy. The piston in each region of the reconstructed wavefront is adjusted by using an iterative algorithm. The present study analyzes and compares the performance of the presented method under different fitting terms, adjustment factors, shear amounts, and initial values of zonal reconstruction. The method can be applied to calibrate piston errors of the segmented wavefront on an aperture of arbitrary shape in zonal reconstruction, and it was validated by simulations and experiments.