20.500.12556/RUL-158171 Mode-shape magnification in high-speed camera measurements If motion, identified using image-based methods, is too small to be seen with the naked eye, motion magnification can be used to help with the visualization. Established motion-magnification methods magnify (typically up to 1000 times) the band-passed content of the image data. Especially at higher frequencies, the amplitudes of measured displacements are often below the noise floor. In this research, a novel method for amplifying vibrations, based on experimental modal analysis (EMA), is introduced. The response of the examined structure to dynamic excitation is measured with a simplified, gradient-based, optical flow method and used to perform a hybrid modal analysis in conjunction with a reference accelerometer response measurement. Such a hybrid approach can: (a) identify structural dynamics significantly in the sub-pixel range, and (b) significantly below the image noise floor. The image of the vibrating structure is subdivided using a planar triangle mesh, which is then warped in accordance with the identified mode shape. A mesh-element-wise affine transformation is performed to obtain an image of the magnified mode shape. In the experimental part, the proposed method achieved magnification factors of approximately 40 thousand times, which is an order of magnitude deeper into noise than available before; additionally, the proposed approach is numerically significantly less demanding. The introduced mode-shape magnification presents an alternative to existing motion-magnification methods for applications where the harmonic displacement information is hidden by image noise. image-based structural identification mode-shape magnification motion magnification DIC optical flow identifikacija struktur na podlagi slikovnega gradiva povečanje nihanja na podlagi modalnih oblik DIC optični tok true false true Angleški jezik Slovenski jezik Članek v reviji 2024-05-27 13:42:52 2024-05-27 13:42:58 2024-06-21 03:36:09 0000-00-00 00:00:00 2024 0 0 15 str. Vol. 213, art. 111336 May 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 519.677:681.7 1096-1216 10.1016/j.ymssp.2024.111336 196821507 1-s2.0-S0888327024002346-main.pdf 1-s2.0-S0888327024002346-main.pdf 1 403FFF18A0A861AD5B668F70AB31EB50 addd8f8d81590ccf0d4c50ea3829d091d3c990e11f4843954dc47d57b63bd601 53130146-1cde-11ef-a9a3-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=185670 https://www.sciencedirect.com/science/article/pii/S0888327024002346 1 443a660c-1c1e-11ef-927e-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=185654 Fakulteta za strojništvo 0 0 0