光电工程, 2013, 40 (6): 37, 网络出版: 2013-08-05
基于格莱姆-施密特正交化两步相移轮廓术
Two-step Phase-shifting Profilometry Based on Gram-Schmidt Orthonormalization
相移法 相位测量轮廓术 变形光栅图 相位去包裹 格莱姆 -施密特正交化法 phase-shifting algorithm phase measuring profilometry (PMP) deformed fringe pattern phase unwrapping Gram–Schmidt (GS) orthonormalization
摘要
将格莱姆 -施密特正交化法引入投影栅形貌测量, 提出了一种新的两步相移轮廓术。首先将 2幅随机相移正弦条纹通过 DLP投影仪投射到待测物体上, 由 CCD相机采集受物体形貌调制的变形光栅条纹图, 再选择合适大小窗口经像素逐点均值法消除变形栅线图中的背景成分, 然后对消背景栅线图进行格莱姆 -施密特正交化, 得到 2幅消背景相移栅线图对应的正交基, 由正交基解调出相位数据。最后对面膜样品进行了实际测量, 并与其它方法进行了比较分析, 实验结果证明了该方法的有效性。
Abstract
A novel two-step phase-shifting profilometry is proposed after the Gram–Schmidt (GS) orthonormalization is introduced into three-dimensional (3D) shape measurement. Firstly, two phase-shifted randomly sinusoidal fringe patterns are projected onto the tested object by Digital-light-processing (DLP) projector. The fringe patterns modulated with theobject’s surface are captured by a CCD camera. Secondly, the background component is eliminated from deformed gratings by averaging method pixel by pixel after the appropriate window size is adopted. Thirdly, an orthonormalized fringe basis is determined from the two fringe patterns using the GS method. Then, the phase is demodulated from the fringe basis. Finally, we have tested the proposed method with real measurement of the human mask. Our algorithm is compared with the other methods. The experimental results are given, which demonstrate the validity of our method.
周灿林, 司书春, 高成勇, 徐建强, 雷振坤. 基于格莱姆-施密特正交化两步相移轮廓术[J]. 光电工程, 2013, 40(6): 37. ZHOU Canlin, SI Shuchun, GAO Chengyong, XU Jianqiang, LEI Zhenkun. Two-step Phase-shifting Profilometry Based on Gram-Schmidt Orthonormalization[J]. Opto-Electronic Engineering, 2013, 40(6): 37.