Quantification of phase-based magnified motion using image enhancement and optical flow techniques
Quantification of phase-based magnified motion using image enhancement and optical flow techniques
复制标题
使用图像增强和光流技术量化基于相位的放大运动
DOI：
10.1016/j.measurement.2021.110508
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发表时间：
2022
期刊：
影响因子：
5.6
通讯作者：
Niezrecki, Christopher
中科院分区：
文献类型：
--
作者：
Valente, Nicholas A.;do Cabo, Celso T.;Mao, Zhu;Niezrecki, Christopher
基于相位的运动放大技术（PMM）以其非侵入性的特性揭示了隐藏的系统动力学，在振动和结构健康监测领域得到了广泛的应用。该方法成功地放大了细微的结构振荡运动，用于系统识别和观察运行形状。尽管这种方法已经实现并且越来越流行，但与放大程度相关的物理运动量尚未被量化。在这项工作中，提出了一个包含振荡几何的合成模拟来量化其放大的像素位移。采用质心检测和光流边缘特征跟踪等计算机视觉技术量化放大与真实运动之间的关系。利用高速光学传感系统在实验结构上对定量技术进行了测试和验证。运动伪影扭曲了放大运动的完整性，这可能会给精确量化带来问题。图像增强技术，如二维维纳滤波器和全变分去噪（TVD）被用来平滑放大后观察到的高频内容。分析了Gabor小波离散漂移的关联误差，证明了空间混叠的合理性。提出了一个调整的放大范围，以显示该技术的局限性，同时提供了对相关误差的洞察。这项工作的结果将有助于将PMM从定性评估工具提高到放大位移的定量测量工具。
Phase-based motion magnification (PMM) has been widely implemented in the field of vibration and structural health monitoring for its non-invasive nature to reveal hidden system dynamics. The approach has shown success in magnifying subtle structural oscillatory motions for system identification and observation of operating shapes. Although this method has been implemented and is becoming increasingly popular, the amount of physical motion associated with the degree of magnification has yet to be quantified. Within this work, a synthetic simulation containing an oscillating geometry is presented to quantify its magnified pixel displacement. Computer vision techniques including centroid detection and edge-feature tracking via optical flow are adopted to quantify the relation between amplification and true motion. The quantification techniques are also tested and verified on an experimental structure with the use of a high-speed optical sensing system. Motion artifacts distort the integrity of the magnified motion, which can pose problems for accurate quantification. Image enhancement techniques such as the two-dimensional Wiener filter and Total Variation Denoising (TVD) are used to smooth the high-frequency content that is observed following magnification. Associative error concerning a discrete shift of the Gabor wavelet is analytically derived to show the justification of spatial aliasing. An adjusted bound on magnification is presented to display the limitations of the technique, while providing insight into associated error. The results of this work will help to enhance PMM from a qualitative evaluation tool to a quantitative measurement tool of magnified displacements.