基于欧拉微动放大的桥梁全息变形形态获取方法

与桥梁变形测量方式中测点分散布置不同,获取桥梁的全息变形行为可以有效地分析其结构变化。采用了基于相位的欧拉影像放大算法,结合视频影像非接触测量的方式,获取桥梁整体的变形形态参数,实现了桥梁全息变形的采集及放大。该方法与数字图像相关方法不同,欧拉放大算法是基于带通滤波并提取相应带通范围内的周期振动信号进行放大。该处理方式适用于桥梁结构这种具有周期性振动的变形特性。采用高速民用摄影机对实验室大跨径自锚式悬索桥缩尺模型进行定点拍摄获取数字影像信息,然后通过基于相位的欧拉影像放大算法将微小的振动形态进行可视化处理,最后利用精简边缘算子实现了桥梁结构边缘的提取。同时结合传统动态位移测量方法获取同期形态变形数据,通过对比分析结果证实了该方法的可行性,为未来利用影像手段进行全息形态获取提供了一种新方法。

Eulerian-based Micro Motion Amplification Method to Measure Holographic Deformation Form of Bridge

Different from the scattered arrangement of measuring points in the traditional bridge deformation measurement method, the holographic deformation behavior of the bridge can effectively analyze its structural changes. In this paper, the phase-based Euler image enlargement algorithm is used to combine the video image non-contact measurement method to obtain the deformation shape parameters of the bridge as a whole, and the acquisition and amplification of the bridge holographic deformation is realized. This method is different from the digital image correlation method (DIC). The Euler amplification algorithm is based on band-pass filtering and extracts the periodic vibration signal in the corresponding bandpass range for amplification. Such a treatment is suitable for a deformation characteristic of a bridge structure having periodic vibration. In this study, a high-speed civilian camera is used to take fixed-point shooting of the laboratory large-span self-anchored suspension bridge scale model to obtain digital image information, and then the phase-based Euler image amplification algorithm is used to visualize the small vibration shape, and finally use the reduced edge. The operator realizes the extraction of the edge of the bridge structure. At the same time, the traditional dynamic displacement measurement method is used to obtain the same shape deformation data. The feasibility of the method is verified by the comparative analysis results, which provides a new method for the future acquisition of holographic morphology by means of imaging. Keywords: Holographic deformation Eulerian Magnification Edge detection algorithm Non-contact measurement