Guangdong Provincial Key Laboratory of Urbanization and Geo-Simulation, School of Geography and Planning, Sun Yat-sen University, Guangzhou 510000, China.
Department of Geomatics Engineering, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada.
Sensors (Basel). 2020 Aug 16;20(16):4594. doi: 10.3390/s20164594.
Pipe elbow joints exist in almost every piping system supporting many important applications such as clean water supply. However, spatial information of the elbow joints is rarely extracted and analyzed from observations such as point cloud data obtained from laser scanning due to lack of a complete geometric model that can be applied to different types of joints. In this paper, we proposed a novel geometric model and several model adaptions for typical elbow joints including the 90° and 45° types, which facilitates the use of 3D point clouds of the elbow joints collected from laser scanning. The model comprises translational, rotational, and dimensional parameters, which can be used not only for monitoring the joints' geometry but also other applications such as point cloud registrations. Both simulated and real datasets were used to verify the model, and two applications derived from the proposed model (point cloud registration and mounting bracket detection) were shown. The results of the geometric fitting of the simulated datasets suggest that the model can accurately recover the geometry of the joint with very low translational (0.3 mm) and rotational (0.064°) errors when ±0.02 m random errors were introduced to coordinates of a simulated 90° joint (with diameter equal to 0.2 m). The fitting of the real datasets suggests that the accuracy of the diameter estimate reaches 97.2%. The joint-based registration accuracy reaches sub-decimeter and sub-degree levels for the translational and rotational parameters, respectively.
管弯头接头几乎存在于每一个支持许多重要应用的管道系统中，例如清洁水供应。然而，由于缺乏适用于不同类型接头的完整几何模型，从激光扫描获得的点云数据等观测结果中很少提取和分析弯头接头的空间信息。在本文中，我们提出了一种新颖的几何模型和几种针对典型弯头接头（包括 90°和 45°类型）的模型适配方法，这使得可以使用从激光扫描收集的弯头接头的三维点云。该模型包括平移、旋转和尺寸参数，不仅可用于监测接头的几何形状，还可用于其他应用，例如点云配准。使用模拟和真实数据集验证了该模型，并展示了从所提出的模型衍生的两个应用（点云配准和支架检测）。模拟数据集的几何拟合结果表明，当引入±0.02m 的随机坐标误差到模拟的 90°接头（直径为 0.2m）时，该模型可以非常精确地恢复接头的几何形状，平移误差（0.3mm）和旋转误差（0.064°）非常小。真实数据集的拟合结果表明，直径估计的精度达到 97.2%。基于接头的配准精度在平移和旋转参数方面分别达到分米和度的级别。
