Optical measurements from high-speed, high-definition video recordings can be used to define the full-field dynamics of a structure. By comparing the dynamic responses resulting from both damaged and undamaged elements, Structural Health Monitoring (SHM) can be carried out, similarly as with mounted transducers. Unlike the physical sensors, which provide point-wise measurements and a limited number of output channels, high-quality video recording allows very spatially dense information. Moreover, video acquisition is a non-contact technique. This guarantees that any anomaly in the dynamic behaviour can be more easily correlated to damage and not to added mass or stiffness due to the installed sensors. However, in real-life scenarios, the vibrations due to environmental input are often so small that they are indistinguishable from measurement noise if conventional image-based techniques are applied. In order to improve the signal-to-noise ratio (SNR) in lowamplitude measurements, Phase-Based Motion Magnification (PBMM) has been recently proposed. This study intends to show that model-based SHM can be performed on modal data and time histories processed with PBMM, whereas unamplified vibrations would be too small for being successfully exploited. All the experiments were performed on a multidamaged box beam with different damage sizes and angles.

中文翻译：

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基于相位的视频放大在操作偏转形状中进行损伤检测和定位的可行性的实验研究

来自高速、高清视频记录的光学测量可用于定义结构的全场动态。通过比较损坏和未损坏元件产生的动态响应，可以执行结构健康监测 (SHM)，类似于安装的换能器。与提供逐点测量和有限数量的输出通道的物理传感器不同，高质量的视频记录允许非常密集的空间信息。此外，视频采集是一种非接触式技术。这保证了动态行为中的任何异常都可以更容易地与损坏相关联，而不是与由于安装的传感器而增加的质量或刚度相关联。然而，在现实生活中，如果应用传统的基于图像的技术，环境输入引起的振动通常很小，以至于无法与测量噪声区分开来。为了提高低幅度测量中的信噪比 (SNR)，最近提出了基于相位的运动放大 (PBMM)。本研究旨在表明基于模型的 SHM 可以对使用 PBMM 处理的模态数据和时间历程执行，而未放大的振动太小而无法成功利用。所有实验均在具有不同损伤尺寸和角度的多损伤箱形梁上进行。本研究旨在表明基于模型的 SHM 可以对使用 PBMM 处理的模态数据和时间历程执行，而未放大的振动太小而无法成功利用。所有实验均在具有不同损伤尺寸和角度的多损伤箱形梁上进行。本研究旨在表明基于模型的 SHM 可以对使用 PBMM 处理的模态数据和时间历程执行，而未放大的振动太小而无法成功利用。所有实验均在具有不同损伤尺寸和角度的多损伤箱形梁上进行。