Vo Quangsang, Fang Fengzhou, Zhang Xiaodong, Gao Huimin
Appl Opt. 2017 Oct 10;56(29):8174-8185. doi: 10.1364/AO.56.008174.
Quality control of micro-nano structured and freeform surfaces is becoming increasingly important, which leads to challenging requirements in the measurement and characterization of rough and highly reflective surfaces. As an important measurement technique, white light scanning interferometry (WLSI) is a fast noncontact method to measure three-dimensional (3D) surface profiles. Nevertheless, the existing WLSI 3D surface reconstruction algorithms are prone to environmental vibrations and phase changes caused by reflections on the tested surface. A novel peak detecting algorithm that combines the white light phase-shifting interferometry (WLPSI) method and fast Fourier transform (FFT) coherence-peak-sensing technique is proposed in this paper, which can accurately determine the local fringe peak and improve the vertical resolution of the measurement. A microcomponent (10 μm standard step height) and a spherical surface were used as test specimens to evaluate the proposed method. Both simulated and experimental results show that the proposed algorithm improves the precision and anti-interference ability of the WLPSI and FFT methods, which can effectively reduce the batwing effects at the edges and solve the problem of positioning error in the maximum modulation.
微纳结构和自由曲面的质量控制变得越来越重要，这对粗糙且高反射表面的测量和表征提出了具有挑战性的要求。作为一种重要的测量技术，白光扫描干涉测量法（WLSI）是一种测量三维（3D）表面轮廓的快速非接触方法。然而，现有的WLSI三维表面重建算法容易受到环境振动以及被测表面反射引起的相位变化的影响。本文提出了一种将白光相移干涉测量法（WLPSI）和快速傅里叶变换（FFT）相干峰值传感技术相结合的新型峰值检测算法，该算法能够准确确定局部条纹峰值并提高测量的垂直分辨率。使用一个微型部件（标准台阶高度为10μm）和一个球面作为测试样本对所提出的方法进行评估。模拟和实验结果均表明，所提出的算法提高了WLPSI和FFT方法的精度和抗干扰能力，能够有效减少边缘处的蝙蝠翼效应并解决最大调制中的定位误差问题。
