A non-contact measurement method is proposed to overcome the shortcomings of traditional contact sensors in this paper. The camera is used as a non-contact virtual sensor of the whole field vibration. The motion in raw video was amplified by Eulerian Video Magnification technology and the gray mean of the selected region from processed video is obtained. The gray value difference between frames represents the dynamic response signal of the local area of the bridge structure under the excitation. The actual displacement amplitude in the time domain of the target structure can be obtained by conversion. A model bridge experiment was carried on, the results show that good coincidence in time domain and good accuracy in frequency domain, the error of the proposed method is 2.2% compared with the traditional measurement, indicating that the method without manual mark has the advantages of accurate, easy to obtain, low cost and high efficiency.
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