为了使相移式横向剪切干涉法能够广泛应用于大口径非球面的在线检测, 通过计算机仿真研究横向剪切干涉测量的非球面面形, 实现其二维波面的重建.分别对仿真中获得的被测非球面在x方向和y方向的两个差分波前中剪切量大小和采样点个数的选取进行分析, 利用最小二乘法求取波差值, 采用Zernike 多项式拟合法进行波前重建, 在保证高准确度测量情况下, 对一被测抛物面面形进行计算机仿真实验, 结果表明: 最适合的剪切量是其被测口径的十分之一大小, 此时只需要对其选取49个离散数据采样点, 采用泽尼克多项式拟合就可得到二维波面的形貌.该结论为相移式横向剪切干涉的二维波前重建提供了理论指导, 同时, 也为大口径非球面在线测量的实际应用提供了技术支撑.

To realize the widely use of phase shift type lateralshearing interferometer in large-diameter aspherical online detection, the measuring for aspherical surface by lateral shearing interferometer was simulated to reconstruct the two dimensional surface. Shearing displacement size and sampling points numbers in the x and y direction of simulated aspheric surfaces were analysed, respectively. By using least squares method to strike waves difference and Zernike polynomial quasi to reconstruct wave-front, a non-spherical surface was simulated. The results indicate that, it′s suitable to set the shearing amount of one-tenth about the size of the aperture to guarantee high precision, and only 49 discrete sampling points are needed to display the two dimensional surface topography by using Zernike polynomial fitting.The conclusion provides a theoretical guidance for the phase shift type two-dimensional wavefront reconstruction of lateral shearing interferometry and technical support for the online practical application of large-diameter aspherical surface measurement.