利用颜色编码辅助计算绝对相位的傅里叶轮廓术

Absolute phase calculation for Fourier transform profilometry with colour coding grating

针对传统去卷积算法时间需求的弊端,提出一种新的使用颜色编码辅助的绝对相位并行计算方法。该算法采用对光栅数目需求最少的傅里叶变换轮廓术(FTP)做为卷积相位求取的方法;颜色编码光栅被用来标识轮廓的序数。直接使用FTP计算出的卷积相位以及从彩色光栅中获得的轮廓序数,即可方便求出当前像素的绝对相位值;同时只用一副图像标识轮廓序数也比其他轮廓序数标识方法简单。本方法由于使用绝对相位计算方法,局部相位误差不会扩展。实验结果也证明了此算法对于多个分离物体以及复杂物体的有效性。

Aiming at the drawback of large time need for traditional phase unwrapping process, a novel method, absolute phase calculation for Fourier transform profilometry（FTP） with col- our coding grating is proposed. Fourier is adopted to calculate the relative phase （wrapped phase） because of the least need of images. Color strips are used to mark each 2n phase-change period. With the two parts, relative phase and fringe orders, the absolute phase can be ob- tained directly. The fringe orders and the relative phase are calculated simultaneously, and this algorithm can circumvent phase unwrapping process. Moreover, errors can not diffuse, be- cause no unwrapping process is needed in our algorithm, and also because the relative phase and fringe orders are uncorrelated. Besides, no need of unwrapping processing and calculating the absolute phase directly in our algorithm can lead to high speed in 3D profile measurement. Experimental results show the validity of our algorithm both for complex object and separate objects.