快速稳定的白光干涉测量法  

Fast and Stable White Light Interferometry

作　　者：董一帆[1] 万新军[1] 孟涵[1] 解树平 

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093

出　　处：《激光与光电子学进展》2017年第5期214-220,共7页Laser & Optoelectronics Progress

基　　金：国家重大科研仪器专项(2012YQ170004)

摘　　要：为了减少白光干涉法的采样数据和计算成本,提高测量速度,提出了一种快速稳定的白光干涉测量方法。根据白光干涉显微镜模型,对光学干涉法的数学模型进行了推导分析,确定了干涉光强函数与包络函数之间的关系。在此基础上,提出利用加大采样间隔的离散采样点的希尔伯特变换函数提取干涉信号包络算法,并基于采样原理分析确定了符合算法的采样间隔条件。通过仿真实验对该算法的有效性进行了验证。实际样品的白光干涉光强信号存在直流(DC)偏置噪声,影响快速白光干涉测量法的稳定性,因此采用中值滤波法消除背景噪声,分析滤波后干涉光强包络的质量。通过白光干涉显微镜装置进行了实际样品白光干涉图像采集,并对不同倍率采样间隔重构的三维表面形貌图进行比较。结果表明,该快速算法重构三维形貌的速度相比传统方法提高了20倍,同时增强了稳定性。To reduce the sampling data and the computational cost of white light interferometry, and improve the measurement speed, fast and stable white light interferometry is proposed. The mathematical model of light interferometry is deduced from the white light interference microscope model, and the relationship between light interference intensity function and envelop function is confirmed. On the basis of these studies, the envelope algorithm of Hilbert transform function extracting interference signal is proposed by increasing the sampling interval of discrete sampling point. And the sampling interval that satisfies the condition of the proposed algorithm is analyzed and determined based on the sampling principle. The algorithm effectiveness is then verified by a simulation test. The white light interference intensity signal of the sample has the direct current （DC） bias noise, which affects the stability of the fast white light interference measurement method. Therefore, median filtering method is used to eliminate background noise. And the quality of the filtered light intensity envelope is analyzed. The white light interference images of the sample are collected by a white light interference microscope, and the three-dimensional surface topographies reconstructed with different sampling intervals are compared. The results show that the envelope algorithm can improve the speed of three-dimensional reconstruction by 20 times compared with the traditional method. Meanwhile, the stability is improved as well.

关 键 词：测量 白光干涉法 三维表面形貌 希尔伯特变换 采样间隔 噪声滤波 

分 类 号：TH744[机械工程—光学工程]