条纹中心法是干涉测量技术中分析单幅干涉图的一种重要处理方法,该方法主要包括图像预处理、波前重构和样品表面形貌及参数的测量等三个部分。研究了条纹中心法的关键技术,特别是应用协方差矩阵法求解泽尼克多项式以进行波前重构的过程。提出了基于单幅干涉图自动波前重构的流程方法。最后应用该流程方法处理由泰曼-格林干涉系统采集的精密抛光铝制盘基片表面形成的一幅干涉图像。实验结果表明,该方法可以实现单幅干涉图的自动波前重构,干涉波前重构的拟合精度可达1.468 6×10-6 nm,还可以自动获得精密抛光铝制盘基片表面的形貌及参数。

The fringe center method (FCM) is an important processing method of the single interferogram analysis for interferometry. It integrates several parts including image preprocessing, wavefront reconstruction, and profile and parameters of the sample surface measured. In this paper, the critical processing technique based on FCM is studied and analyzed, especially the technique that solving Zernike polynomial by using covariance matrix method to reconstruct the wavefront. The automatic processing flow and method of the wavefront reconstruction based on the single interferogram are proposed. With the flow and method, the interferogram of the fine polished aluminum disk surface captured by the Twyman-Green interferometer is processed. The experiments show that the wavefront reconstruction based on the single interferogram can be realized automatically and the fitting precision of the wavefront reconstruction is 1.468 6×10-6 nm, and the profile and parameters of the disk surface can also be obtained automatically.