光纤式色散共焦三维测量系统及算法比较研究

Fiber-coupled Chromatic Confocal 3D Measurement System and Comparative Study of Spectral Data Processing Algorithms

利用Zemax优化设计了结构简单、低成本的非球面色散镜组,搭建了光纤式色散共焦三维测量软硬件系统。结合实验测试数据定量比较了峰值法、质心法、高斯拟合法和样条插值法的色散共焦光谱响应峰值波长提取性能,通过轴向分辨率和位移精度测试实验对比分析了两种测量曲线标定方法对于系统测量性能的影响。实验结果表明:系统轴向测量范围为1 mm,高斯拟合法在四种峰值波长提取算法中精度较高且适应性更好,两种标定方法对应的轴向分辨率均达到0.2μm,在整个量程范围内,位移测量精度优于1%;对厚度为0.219 mm的石英玻璃进行测量,均值的相对误差为0.5%。利用该系统实际测量了台阶结构、柔性电极和MEMS器件的三维形貌,充分验证了本系统可实际应用于三维微观形貌和透明材料厚度的高精度测量。

A simple aspheric chromatic dispersion lens group of low cost is designed using Zemax,and an integrated fiber-coupled chromatic confocal 3D measurement system is developed.Performances of four peak wavelength extraction methods,i.e.the maximum method,centroid method,Gaussian fitting method and spline interpolation method,have been compared and analyzed quantitatively.In addition,calibration accuracy of Gaussian fitting method and spline interpolation method is tested and compared through the axial resolution and displacement measurement experiments.The experimental results show that the axial measurement range of the built system is 1 mm.The Gaussian fitting method has higher accuracy and better stability among the four peak extraction algorithms.The axial resolution of the system using Gaussian fitting based and spline interpolation based calibration methods can both reach 0.2μm and the displacement measurement accuracy is better than 1%within the whole measurement range;a quartz glass with a thickness of 0.219 mm is measured,and the relative measurement error of the average value is 0.5%.Finally,the developed system is applied to the 3D surface measurement of a step structure,a flexible electrode and a MEMS unit,and the experimental results indicate that the proposed system can perform high-precision 3D measurements of complex microstructures and transparent material thicknesses.