Gu Feifei, Song Zhan, Zhao Zilong
Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Mechanical and Automation Engineering Department, The Chinese University of Hong Kong, Hong Kong, China.
Sensors (Basel). 2020 Feb 17;20(4):1094. doi: 10.3390/s20041094.
Structured light (SL) has a trade-off between acquisition time and spatial resolution. Temporally coded SL can produce a 3D reconstruction with high density, yet it is not applicable to dynamic reconstruction. On the contrary, spatially coded SL works with a single shot, but it can only achieve sparse reconstruction. This paper aims to achieve accurate 3D dense and dynamic reconstruction at the same time. A speckle-based SL sensor is presented, which consists of two cameras and a diffractive optical element (DOE) projector. The two cameras record images synchronously. First, a speckle pattern was elaborately designed and projected. Second, a high-accuracy calibration method was proposed to calibrate the system; meanwhile, the stereo images were accurately aligned by developing an optimized epipolar rectification algorithm. Then, an improved semi-global matching (SGM) algorithm was proposed to improve the correctness of the stereo matching, through which a high-quality depth map was achieved. Finally, dense point clouds could be recovered from the depth map. The DOE projector was designed with a size of 8 mm × 8 mm. The baseline between stereo cameras was controlled to be below 50 mm. Experimental results validated the effectiveness of the proposed algorithm. Compared with some other single-shot 3D systems, our system displayed a better performance. At close range, such as 0.4 m, our system could achieve submillimeter accuracy.
结构光（SL）在采集时间和空间分辨率之间存在权衡。时间编码的结构光可以生成高密度的三维重建结果，但不适用于动态重建。相反，空间编码的结构光单次工作，但只能实现稀疏重建。本文旨在同时实现精确的三维密集和动态重建。提出了一种基于散斑的结构光传感器，它由两个相机和一个衍射光学元件（DOE）投影仪组成。两个相机同步记录图像。首先，精心设计并投射散斑图案。其次，提出了一种高精度校准方法来校准系统；同时，通过开发优化的极线校正算法精确对齐立体图像。然后，提出了一种改进的半全局匹配（SGM）算法来提高立体匹配的正确性，从而获得高质量的深度图。最后，可以从深度图中恢复密集点云。DOE投影仪的尺寸设计为8毫米×8毫米。立体相机之间的基线控制在50毫米以下。实验结果验证了所提算法的有效性。与其他一些单次三维系统相比，我们的系统表现出更好的性能。在近距离，如0.4米处，我们的系统可以达到亚毫米级精度。
