利用激光扫描技术进行变形监测的原理,针对所监测的区域通过对比分析不同时段所测得的点云数据,确定监测对象中的变形区域与变形量。与传统的单点测量技术相比,三维激光扫描技术具有效率高、精度高、测量数据量大等优点,然而在应用该技术进行变形监测时,对于监测结果的可靠性并未作出评价。因此,需要对点云误差进行分析,并由此确定点云变形可监测指标。在确定点云误差空间时,引入误差熵来消除相邻点之间的误差影响,以及控制误差空间不确定性的影响。根据误差熵与误差极值的关系,最终确定点云变形可监测指标。利用平面板模拟实验,验证该指标的可行性,然后将其应用于桥梁的变形监测中。

The principle of three-dimensional(3D) laser scanning technology for deformation monitoring is to analyze the point cloud data measured at different time intervals and determine the deformation area and the deformation amount in the monitoring object based on the contrast of the obtained data. Compared with the traditional single-point measurement technology, the 3D laser scanning technology has advantages such as high efficiency, high precision and large amount of measurement data. However, no evaluation is made on the reliability of monitoring results when applying this technology for deformation monitoring. Therefore, it is necessary to analyze the point cloud error and determine the indicators of point cloud deformation monitoring. In determining the point cloud error space, we introduce the error entropy to eliminate the influence of the error between adjacent points and control the influence of the uncertainty of the error space. According to the relationship between the error entropy and the extreme value of the error, the indicators of point cloud deformation monitoring can be finally determined. The feasibility of the indicators are verified based on the flat panel simulation experiment, and then applied to the bridge deformation monitoring.