结构动态位移远距离摄像测量精度评价

Accuracy assessment of long-range videogrammetrey for structural dynamic displacements

位移是评估结构性能和安全的重要参数.摄像测量有望成为一种实用的位移测量方法,但其远距离摄像测量精度有待研究.以不同测量距离所测得的位移数据为研究对象,开展了结构动态位移远距离摄像测量精度试验,分析了测量距离对摄像测量精度的影响.结果表明:测量距离和目标点振动频率增加将对测量精度产生显著影响,导致测量精度大幅降低;摄像测量系统在510m范围内仍具有较高的测量精度,满足工程测量的要求;对广州新电视塔位移数据分析可知,测量距离增加对结构动态位移频率测量精度的影响较小.

The displacement is an important parameter for evaluating the behavior and safety of a structure. Videogrammetry is expected to be a practical displacement measurement method, but the accuracy of long-range videogrammetrey needs to be studied. With the displacement data obtained from different measuring distances as the study objective, a measuring accuracy test of long-range videogrammetrey for the dynamic displacements of structures is conducted. The effect of the measuring distance on the measuring accuracy of videogrammetrey is analyzed. It is shown that the measuring distance and the vibration frequency of the target point have a marked effect on the accuracy of videogrammetry, resulting in a significant decrease in measuring accuracy. When the measuring distance is smaller than 510 meters, the measuring accuracy of videogrammetry is still high and meets the monitoring requirements of engineering structures. Based on the analysis of the dynamic displacement data of the Canton Tower, it is found that increasing measuring distance has little influence on the dynamic displacement frequency of structures.