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  • High-speed camera based experimental modal analysis based on pixel intensities [Elektronski vir] = Eksperimentalna modalna analiza s hitro kamero na podlagi intenzitete slikovnih točk
    Tomac, Ivan ; Gorjup, Domen, 1992- ; Slavič, Janko, 1978-
    Modal identification with high-speed cameras is a challenging task. The displacements measured in this way are in the range of one hundredth or even one thousandth of a pixel. Such displacements are ... at the level of the camera-sensor noise and are also affected by the low dynamic range of the sensor AD converter. Nowadays, a typical approach is to first obtain full-field displacements from the high-speed video recording using the digital image correlation (DIC) method, which is computationally intensive. Then in the next step perform modal identification based on the identified displacements. Optical flow is a method based on the change in intensity in each pixel due to the change in reflection from a moving surface. To detect displacement, knowledge of the spatial gradient is required. If the movement is in the sub-pixel range, a linear relationship can be assumed between the change in pixel intensity and the displacement. This opens the possibility to perform the modal identification directly based on the pixel intensities. Since pixel intensities are usually highly noisy, a method is needed that can identify modal parameters from such signals. A recently introduced method based on the Morlet-wave integral is used here to identify modal parameters. The method has good time-frequency separation which enables identification from just a fraction of the signal in time-frequency domain. Such an approach opens up possibility to transform the pixel intensities directly into the modal domain, where further processing can be done with a much smaller amount of data. The presented method was successfully applied to the experimental test case, where a pixel-based, full-field modal analysis was performed. The influence of averaging the results from several pixels in the modal domain is investigated.
    Source: Kuhljevi dnevi 2023 [Elektronski vir] : zbornik del : Bled, 21.–22. september 2023 (Str. 202-210)
    Type of material - conference contribution ; adult, serious
    Publish date - 2023
    Language - english
    COBISS.SI-ID - 165948675

    Link(s):

    http://www.drustvozamehaniko.si/zbornik/ZbornikKD2023.pdf

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