Vibration Sensing of a Bridge Model Using a Multithread Active Vision System
Vibration Sensing of a Bridge Model Using a Multithread Active Vision System
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DOI：
10.1109/tmech.2017.2764504
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发表时间：
2018-02-01
影响因子：
6.4
通讯作者：
Fujiwara, Akimasa
中科院分区：
文献类型：
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作者：
Aoyama, Tadayoshi;Li, Liang;Fujiwara, Akimasa
本研究提出了一种多线程主动视觉传感的概念，可以测量土木工程结构上多点动态变化的位移和振动。在多线程主动视觉传感中，高速摄像机通过毫秒级的超快视点切换加速其测量、计算和驱动，可以实现多台跟踪摄像机的虚拟功能。这使得可以同时测量分布在大范围内的小振动，这是无法使用单个相机系统观察到的，因为它的像素精度通常与广角视角不兼容。我们开发了一个基于振镜的高速多线程主动视觉系统，可以在一秒钟内切换500个不同的视图；它由15个虚拟摄像机组成，每个虚拟摄像机以33.3 FPS的速度运行，以完全不同的视角观察多个场景。对一个带有15个标记的4 m长桁架结构桥梁模型的实验结果表明，单个主动视觉系统可以在几十赫兹的频率上观察桥梁结构的变形，并估计出共振频率和模态振型等模态参数。
This study proposes a concept for multithread active vision sensing that can measure dynamically changing displacement and vibration at multiple points on civil engineering structures. In multithread active vision sensing, a high-speed camera can function virtually as multiple tracking cameras by accelerating its measurement, computation, and actuation with ultrafast viewpoint switching at millisecond level. This enables simultaneous measurement of small vibrations distributed across a wide range, which cannot be observed using a single camera system, because its pixel accuracy is generally incompatible with its wide angle of view. We developed a galvanomirror-based high-speed multithread active vision system that can switch 500 different views in a second; it functioned as 15 virtual cameras each operating at 33.3 fps to observe multiple scenes in completely different views. The experimental results for a 4-m-long truss-structure bridge model to which 15 markers were attached show that a single active vision system can observe the deformation of the bridge structure and estimate modal parameters, such as resonant frequencies and mode shapes, at a frequency on the order of dozens of hertz.