高精度动态白光干涉测量方法

High-Precision Dynamic White-Light Interferometry

白光干涉测量技术具有精度高和非接触式测量的优点,是超精密加工领域中的一项重要测量手段。针对白光干涉测量技术容易受环境振动影响的问题,提出了一种动态垂直扫描干涉测量方法(DVSI)。该方法将白光干涉光路分为两个成像通道,得到与白光干涉图同步移相的准单色光干涉图。通过相位-倾斜迭代方法(PTI)对准单色光干涉图进行处理得到实际的移相扫描位置,对白光干涉信号进行相干峰位置的定位,并计算出粗糙的形貌分布,之后利用局部最小二乘方法(LLS)计算出精细的相位分布,将粗糙形貌以及精细相位相结合来复原出待测件的三维形貌。本研究通过数值仿真和实验对比对该方法进行了验证,结果表明本方法具有较好的抗振性能。

White-light interferometry has the advantages of high accuracy and non-contact measurement, which is an important measurement method in the field of ultra-precision machining. To tackle the problem that white-light interferometry is easily affected by environmental vibration, dynamic vertical scanning interferometry(DVSI) is proposed. This method divides the white-light interferometric optical path into two imaging channels to generate a quasi-monochromatic light interferogram, which is phase-shifted synchronously with the white-light interferogram. We obtain the actual phase-shift scanning position by processing the quasi-monochromatic light interferogram through the phase-tilt iteration(PTI), after which the coherence peak of the white-light interference signal is located and the coarse topographic distribution is calculated. The local least square(LLS) is used to calculate the fine phase distribution. The coarse topographic distribution and fine phase distribution are combined to recover the three-dimensional topography of the tested sample. The method is verified through numerical simulation and experimental comparison, and the results show that the method has good vibration-resistant performance.