Meng Wang, Quanyao Hou, Yongkai Yin, Yang Yang, Qijian Tang, Xiang Peng, Xiaoli Liu
Opt Express. 2022 Feb 28;30(5):8015-8026. doi: 10.1364/OE.452361.
Fringe projection profilometry (FPP) has been widely researched for three-dimensional (3D) microscopic measurement during recent decades. Nevertheless, some disadvantages arising from the limited depth of field and occlusion still exist and need to be further addressed. In this paper, light field imaging is introduced for microscopic fringe projection profilometry (MFPP) to obtain a larger depth of field. Meanwhile, this system is built with a coaxial structure to reduce occlusion, where the principle of triangulation is no longer applicable. In this situation, the depth information is estimated based on the epipolar plane image (EPI) of light field. In order to make a quantitative measurement, a metric calibration method which establishes the mapping between the slope of the line feature in EPI and the depth information is proposed for this system. Finally, a group of experiments demonstrate that the proposed LF-MFPP system can work well for depth estimation with a large DOF and reduced occlusion.
近几十年来，条纹投影轮廓术（FPP）已被广泛用于三维（3D）微观测量。然而，由于景深有限和遮挡而产生的一些缺点仍然存在，需要进一步解决。本文将光场成像引入微观条纹投影轮廓术（MFPP）以获得更大的景深。同时，该系统采用同轴结构构建以减少遮挡，在此情况下三角测量原理不再适用。在这种情况下，基于光场的极平面图像（EPI）估计深度信息。为了进行定量测量，针对该系统提出了一种度量校准方法，该方法建立了EPI中线特征的斜率与深度信息之间的映射。最后，一组实验表明，所提出的LF-MFPP系统在大景深和减少遮挡的情况下进行深度估计时能够很好地工作。
