摘要
针对传统接触式传感器获取桥梁结构振动信息的不足,提出了一种基于欧拉影像放大技术和边缘灰度均值差的非接触式测量方法,该方法将摄像机作为全场振动的非接触式虚拟传感器,拍摄桥梁结构在激励后的整体或局部响应影像数据,利用欧拉微动视频放大技术对获取的影像数据进行微小运动放大处理。对处理后的影像数据进行结构局部边界区域灰度均值提取,同时计算该区域内像素的灰度均值差。差值表征了桥梁结构在激励作用下该局部区域的动态响应信号,该值与结构的实际位移存在着一个线性比例关系,通过标定即可获取目标结构时域中的实际位移幅值。该方法在一个模型悬索桥上进行了试验研究,同时对一座在役斜拉桥的现场测试进行了分析研究,结果表明该方法能够实现常规接触式振动传感器的功能,同时相比于传统的摄影测量,本边缘区域均值差法大大提高了信噪比,其精度与传统振动测量方法相比误差区间在(2%~7%)。该方法具体快捷、高效、易于获取等优点(成本低、效率高),同时其测量精度与传统振动测量方法相当,并且为获取结构全息动力特性参数提供了一种测量手段。
Aiming at the shortcomings of traditional contact sensors in obtaining vibration information of bridge structures,a non-contact measurement method based on Euler image magnification technology and edge gray level difference is proposed.In this method,the camera is used as a full-field vibration non-contact virtual sensor,which captures the overall or local response to the image data of the bridge structure after excitation,and uses Euler micro-motion video magnification technology to magnify the acquired image data with small motion.Extract the average gray value of the local boundary area of the processed image data,and calculate the average gray value difference of the pixels in the area.The difference characterizes the dynamic response signal of the local area of the bridge structure under the excitation.There is a linear proportional relationship between the value and the actual displacement of the structure.The actual displacement amplitude in the time domain of the target structure can be obtained by calibration.This method has been experimentally studied on a model suspension bridge and a cable-stayed bridge in service.The results show that the method can achieve the function of a conventional contact vibration sensor,and meanwhile,compared with the traditional photogrammetry,the mean difference method of the edge area is greatly improved In order to obtain the signal-to-noise ratio,the relative error interval is(2%~7%)compared with the traditional vibration measurement method.The method is specific,fast,efficient,and easy to obtain(low cost and high efficiency).At the same time,its measurement accuracy is equivalent to traditional vibration measurement methods,and it provides a measurement method for obtaining structural holographic dynamic characteristic parameters.
作者
郑佳艳
毛若愚
吴桐
唐亮
周志祥
ZHENG Jiayan;MAO Ruoyu;WU Tong;TANG Liang;ZHOU Zhixiang(State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《公路工程》
2021年第3期45-53,187,共10页
Highway Engineering
基金
国家自然科学基金项目(51778094
51708068)
重庆市研究生科研创新项目(CYS19241)。
关键词
桥梁结构
振动特性
欧拉微动放大
灰度均值差
虚拟传感器
bridge structure
vibration characteristics
euler micro-motion amplification
gray mean difference
virtual sensor
