光电工程, 2013, 40 (10): 1, 网络出版: 2013-10-23
基于对称判据的白光干涉零光程位置拾取算法
A Zero OPD Location Algorithm for WLI Based on the Symmetry Criterion
摘要
高性能白光干涉测量技术的发展对零光程位置精确拾取提出了更高的要求。基于白光干涉光强对称分布特点设计了对称性判据, 并根据此判据和实际采样数据的离散性, 提出了一种白光干涉零光程位置拾取算法。算法分为两步: 首先, 从数据中寻找最大测量峰值, 然后搜索最大峰值附近的子峰, 利用对称性判据及其变化趋势来确定最接近的零光程位置的子峰; 接着, 由于采样点的离散性, 需要进一步对搜寻到的子峰进行局部数据拟合, 通过拟合峰值最终确定零光程干涉峰值和零光程位置。此时对称性判据还可用于评估零光程拟合位置与真实位置间距。通过实测数据处理和算法对比实验表明: 该算法能够进一步提高零光程位置辨别能力和拾取精度, 保障高性能白光干涉测量设备的超精密测试需求。
Abstract
A symmetry criterion is designed according to the irradiance distribution characteristic of White Light Interference (WLI). A zero Optical Path Difference (OPD) location algorithm is presented based on the symmetry criterion and discreteness of sample. The location algorithm consists of two steps: 1) Using the symmetry criterion and its variation trend to search and locate the measurement sub-peak around the maximal value in the data, which is the closest to the zero OPD; 2) Using fitting method to further locate the zero OPD and peak value based on the located sub-peak in the step 1. The location validity can also be evaluated by the symmetry criterion. The experiment of data processing and algorithm comparison shows that this location algorithm has advantage of discriminating and pick up zero OPD, which can meet the measurement need of the high precision WLI instrument.
蒋大钢, 杨远洪, 秦开宇. 基于对称判据的白光干涉零光程位置拾取算法[J]. 光电工程, 2013, 40(10): 1. JIANG Dagang, YANG Yuanhong, QIN Kaiyu. A Zero OPD Location Algorithm for WLI Based on the Symmetry Criterion[J]. Opto-Electronic Engineering, 2013, 40(10): 1.