Railroad bridge inspection manuals recommend measuring bridge displacements under train crossing events. Traditional displacement measurement methods require humans climbing the infrastructure for sensor installation, which is unsafe. Therefore, bridge inspectors are interested in noncontact methods. The authors of this paper developed a methodology that measures the noncontact, reference‐free total transverse displacement of structures using a laser and a camera. Total displacement refers to both dynamic and pseudostatic components of displacement. The developed method can be implemented with off‐the‐shelf hardware components that are lightweight, and simple enough, so researchers can build their own system and test it in the field. First, the paper presents the methodology and tests it with a 1 degree of freedom (DOF) estimation with neither rotation nor elevation change. Subsequently, authors developed a new algorithm combining both laser and camera under arbitrary 6 DOF motion. The results of this research support noncontact reference‐free total displacement measurements of railroad bridges.

中文翻译：

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一种使用激光摄像机系统测量结构总位移的方法

铁路桥梁检查手册建议在火车穿越事件下测量桥梁位移。传统的位移测量方法要求人类攀爬传感器安装的基础设施，这是不安全的。因此，桥梁检查员对非接触式方法很感兴趣。本文的作者开发了一种方法，该方法使用激光和照相机来测量结构的非接触式，无参考值的总横向位移。总位移是指位移的动态分量和伪静态分量。开发的方法可以使用重量轻且足够简单的现成硬件组件实现，因此研究人员可以构建自己的系统并在现场进行测试。第一的，本文介绍了该方法，并以1自由度（DOF）估计进行了测试，既没有旋转也没有高度变化。随后，作者开发了一种在任意6自由度运动下将激光和相机结合在一起的新算法。这项研究的结果支持铁路桥梁的非接触无参考总位移测量。