ABSTRACT A wide spectrum of Large-Scale Metrology instruments for measuring 3D positions of mobile targets with different levels of accuracy, operational ranges and corresponding cost exist. However, future assembly paradigms and further industrial applications would benefit from a system with ultra low-cost targets and an accuracy in the order of magnitude of 1 mm, which is currently not available. Therefor the authors propose a camera-based tracking theodolite as a novel instrument for measuring 3D positions of printed visual markers. The approach is implemented as a prototype composed of two rotation stages with built-in encoders, a state-of-the-art industrial CMOS-camera and lens with fixed focal length in conjunction with printed chessboard targets. According mathematical models for the calculation of the targets’ position, kinematic error compensation and measurement uncertainty estimation are elaborated. Competitive experiments against a laser tracker show that the position of the marker can be measured with an absolute error below 1 mm and a statistical uncertainty close to 1 mm in a radius of 5 m, confirming the applicability of the developed concept for a novel Large-Scale Metrology instrument.

中文翻译：

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用于大规模计量应用的低成本基于相机的跟踪经纬仪

摘要 存在多种用于测量具有不同精度、操作范围和相应成本的移动目标的 3D 位置的大规模计量仪器。然而，未来的组装范例和进一步的工业应用将受益于具有超低成本目标和 1 毫米数量级精度的系统，目前尚不可用。为此，作者提出了一种基于相机的跟踪经纬仪作为测量印刷视觉标记的 3D 位置的新型仪器。该方法被实施为一个原型，由两个带有内置编码器的旋转台、一个最先进的工业 CMOS 相机和具有固定焦距的镜头以及印刷棋盘目标组成。根据计算目标位置的数学模型，详细阐述了运动误差补偿和测量不确定度估计。针对激光跟踪器的竞争性实验表明，可以在 5 m 半径内以低于 1 mm 的绝对误差和接近 1 mm 的统计不确定性测量标记的位置，这证实了所开发概念对于新型大尺寸的适用性。秤计量仪器。