基于数字图像技术的桥梁动态位移测量应用研究

Research on the measurement of dynamic displacement of bridge based on digital image processing techniques

文章开发了一套基于数字图像处理技术的桥梁动态位移测量系统。该系统对采集的光斑图像进行二值化及图像滤波处理,进而搜索光斑中心在像素坐标下的变化来求其空间坐标,以达到识别桥梁动态位移的目的。为证实该系统测量的可行性与准确性,在实验室进行了精度实验,静载、动载测量以及实桥测试。同时用该系统采集的位移数据进行频谱分析,频谱结果与其理论基频吻合。结果表明,在测量环境不变的前提下,该系统的测量结果与其对比方法测量结果基本一致,系统测量精度在毫米级情况下频谱分析所求得的频率结果较为准确,满足桥梁位移测量与基本动态特性分析的需要。

A measurement system based on digital image processing was developed for identifying the dynamic displacement of bridge. In the system, light spot-images were first binarized and filtered, and then the displacement coordinates of bridge were calculated through the center coordinates of the light spot-images. To verify the feasibility and the accuracy of the measurement system, an accuracy test and a series of static load- ing and dynamic loading experiments were carried out in laboratory and a field dynamic experiment was conducted on a real bridge. Meanwhile, spectrum analyses were conducted by utilizing the data of this system acquired, and the results were in accordance with those of theoretical fundamental frequency. It is shown that under the same measurement environment, the displacements acquired by image processing accord with the values measured by the comparative methods, the accuracy of this measurement system maintains at millimeter-level, and the frequency of bridges calculated by using image processing data is accurate, which satisfies the requirement of displacement measurement of bridge and basic analysis of dynamic performance.