光学学报, 2011, 31 (11): 1111002, 网络出版: 2011-10-27
三维成像中相位级次自编码的相位测量方法
A Novel Phase Order Self-Encoding Technique for Phase Measuring Profilometry
成像系统 自编码 相移 结构光照明 三维成像 机器视觉 imaging systems self encoding phase shift structured-light illumination three-dimensional imaging machine vision
摘要
提出一种相位级次自编码技术的相位测量方法。与传统的相位测量技术不同,该方法利用截断相位的微分值作为编码通道,完成对各条纹级次的编码。构造的代码序列总长度为投影条纹的周期数,每个周期作为一个码元,由相邻若干码元构成一个代码子序列。相位计算后,根据截断相位的微分信息,可以提取出各周期及其码元值,通过在设计的代码序列中进行代码子序列匹配,即可确定各周期的序号,从而引导相位展开,获得绝对相位分布。采用希尔伯特变换对因编码引起的局部相位误差进行了有效修正。该方法通过将编码信息加载于截断相位分布中,在计算截断相位的同时获得相位级次信息,不需要投影额外的编码图像,测量速度快,尤其适用于孤立物体的三维面形测量。
Abstract
The phase measuring profilometry using a novel phase order self-encoding technique is presented, which is to use the differential of the wrapped phase as the encoded information to identify all periods of the grating. The length of the encoded sequence is the same as the number of periods. There is only one code value in one period, which can be identified by the information of the differential and phase jumps. For each period, the information of its several neighboring periods will form a subsequence, which is unique and can be used to find the order of each period. The absolute phase can be got after getting the order. To revise the phase errors at some phase-jump areas, Hilbert transform is employed. By embedding the encoded information in the wrapped phase, there is no extra grating needing projecting, and there is also no classical phase unwrapping process. It is promising in measuring the surface profile of the spatially isolated objects.
刘元坤, 苏显渝, 张启灿. 三维成像中相位级次自编码的相位测量方法[J]. 光学学报, 2011, 31(11): 1111002. Liu Yuankun, Su Xianyu, Zhang Qican. A Novel Phase Order Self-Encoding Technique for Phase Measuring Profilometry[J]. Acta Optica Sinica, 2011, 31(11): 1111002.