Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, ND 58108, USA.
Sensors (Basel). 2023 Mar 15;23(6):3152. doi: 10.3390/s23063152.
Displacement is critical when it comes to the evaluation of civil structures. Large displacement can be dangerous. There are many methods that can be used to monitor structural displacements, but every method has its benefits and limitations. Lucas-Kanade (LK) optical flow is recognized as a superior computer vision displacement tracking method, but it only applies to small displacement monitoring. An upgraded LK optical flow method is developed in this study and used to detect large displacement motions. One motion controlled by a multiple purpose testing system (MTS) and a free-falling experiment were designed to verify the developed method. The results provided by the upgraded LK optical flow method showed 97 percent accuracy when compared with the movement of the MTS piston. In order to capture the free-falling large displacement, the pyramid and warp optical flow methods are included in the upgraded LK optical flow method and compared with the results of template matching. The warping algorithm with the second derivative Sobel operator provides accurate displacements with 96% average accuracy.
当涉及到土木工程结构的评估时，位移是至关重要的。大位移可能是危险的。有许多方法可以用于监测结构位移，但每种方法都有其优点和局限性。Lucas-Kanade（LK）光流被认为是一种优越的计算机视觉位移跟踪方法，但它仅适用于小位移监测。本研究提出了一种改进的 LK 光流方法，用于检测大位移运动。设计了一个由多用途测试系统（MTS）和自由落体实验控制的运动，以验证所提出的方法。与 MTS 活塞的运动相比，改进后的 LK 光流法提供的结果准确率达到 97%。为了捕捉自由落体的大位移，金字塔和光流 warp 方法被包含在改进的 LK 光流方法中，并与模板匹配的结果进行了比较。带有二阶导数 Sobel 算子的 warp 算法提供了准确的位移，平均准确率为 96%。
