基于网络摄像机的桥梁挠度非接触识别

针对传统的桥梁挠度识别系统可达性差、效率低、不能全天候实时监测，建立了一种基于网络摄像机的桥梁挠度非接触识别系统。系统采用LED光源作为标志物，以网络摄像机作为采集设备，通过无线传输图像信息，利用计算机搭载基于HSV的快速模板匹配和基于颜色追踪(cvCamShift)的几何匹配算法获取目标的挠度时程信息，进而实现对桥梁挠度的非接触识别。通过在人行桥模型上进行四种工况的振动试验以及现场实桥测试，以此验证系统的可行性。研究结果表明:在模型试验中，系统识别得到的时域和频域信息与激光位移传感器对比的误差都小于0.6%，在雾气干扰下识别的误差仍可小于0.7%；实桥测试下，系统的识别结果与桥梁挠度仪对比的误差小于1.9%。由此表明系统鲁棒性强且经济性好，具备广泛的应用前景。

NON-CONTACT IDENTIFICATION OF BRIDGE DEFLECTION BASED ON NETWORK CAMERA

A non-contact identification system of bridge deflection based on network cameras is established to solve the problem of poor accessibility, of low efficiency, and of incompetence in all-weather real-time monitoring of the traditional bridge deflection identification system. The system used LED (light-emitting diode) lights as the marker and took network cameras as the acquisition equipment to transmit the image information wirelessly, the deflection time history information of the target is obtained by using the computer carries HSV (hue, saturation, and value) based on fast template matching and color tracking (cvCamShift) based on geometric matching algorithm, and then the non-contact identification of bridge deflection can be realized. The feasibility of the system is verified by the vibration tests under four working conditions on the footbridge model and the field test of a real bridge. The results show that: in the model test, the error of the time domain and of the frequency domain information identified by the system compared with the laser displacement sensor is less than 0.6%, and the error can still be less than 0.7% under the interference of fog. Under the real bridge test, the error of the system identification results is less than 1.9% compared with the bridge deflection instrument. This indicates that the system has strong robustness and good economy and has a wide application prospect.