[论文解读] One shot profilometry using iterative two-step temporal phase-unwrapping

Guangliang Du, Minmin Wang+5 more|arXiv (Cornell University)|May 19, 2016

Optical measurement and interference techniques被引用 3

一句话总结

本文提出一种结合复合条纹投影与迭代两步时间相位解包裹算法的一次性3D轮廓测量方法，实现单次采集下的快速、高精度形状测量。通过利用包含四个频率分量的单一复合条纹图案，并迭代优化相位解包裹，该方法在保持速度的同时，相比以往的一次性方法显著提升了精度。

ABSTRACT

This paper reviews two techniques that have been recently published for 3D profilometry and proposes one shot profilometry using iterative two-step temporal phase-unwrapping by combining the composite fringe projection and the iterative two-step temporal phase unwrapping algorithm. In temporal phase unwrapping, many images with different frequency fringe pattern are needed to project which would take much time. In order to solve this problem, Ochoa proposed a phase unwrapping algorithm based on phase partitions using a composite fringe, which only needs projecting one composite fringe pattern with four kinds of frequency information to complete the process of 3D profilometry. However, we found that the fringe order determined through the construction of phase partitions tended to be imprecise. Recently, we proposed an iterative two-step temporal phase unwrapping algorithm, which can achieve high sensitivity and high precision shape measurement. But it needs multiple frames of fringe images which would take much time. In order to take into account both the speed and accuracy of 3D shape measurement, we get a new, and more accurate unwrapping method based on composite fringe pattern by combining these two techniques. This method not only retains the speed advantage of Ochoa's algorithm, but also greatly improves its measurement accuracy. Finally, the experimental evaluation is conducted to prove the validity of the proposed method, and the experimental results show that this method is feasible.

研究动机与目标

• 解决3D轮廓测量中测量速度与精度之间的权衡问题。
• 克服Ochoa基于相位分区的一次性方法中条纹序数估计不精确的问题。
• 将高精度的迭代两步时间相位解包裹算法与复合条纹投影相结合，实现一次性操作。
• 在无需多帧相位移位图像的情况下，实现快速、精确的3D形状重建。

提出的方法

• 将包含四个不同频率分量的单一复合条纹图案投射到物体表面。
• 利用时间相位解包裹技术提取复合图案中的相位信息。
• 应用迭代两步时间相位解包裹算法，以高精度解决相位模糊问题。
• 通过最小化相位不连续性并逐步优化，迭代改进解包裹后的相位图。
• 通过在单个图案中实现频率复用，将一次性采集的速度优势与多帧解包裹的精度相结合。
• 采用基于分区的方法对复合条纹进行相位解包裹，并通过迭代优化减少误差。

实验结果

研究问题

• RQ1 一次性3D轮廓测量系统能否实现与多帧时间相位解包裹方法相当的高测量精度？
• RQ2 如何在不增加采集时间的前提下，提升Ochoa复合条纹方法的相位解包裹精度？
• RQ3 迭代优化在单一复合条纹图案中的相位解包裹精度提升程度如何？
• RQ4 复合条纹投影与迭代两步解包裹的结合能否实现实时、高精度的3D形状测量？
• RQ5 频率复用对一次性轮廓测量中相位模糊性解决的影响是什么？

主要发现

• 所提出的方法仅通过一次条纹图案投射即可实现高精度的3D形状测量。
• 迭代两步解包裹算法相比传统一次性方法显著提升了相位解包裹的精度。
• 该方法在保持一次性采集速度优势的同时，克服了以往复合条纹技术中条纹序数估计不精确的问题。
• 实验结果验证了该方法在实际3D轮廓测量应用中的可行性与有效性。
• 复合条纹投影与迭代解包裹的结合，实现了在复杂表面测量中误差更少的鲁棒相位重建。