Image-based displacement measurement methods are increasingly being used in the field of structural dynamics, the main reasons being their non-contacting operation and high spatial resolution, facilitating full-field vibration measurements. By utilizing multiple calibrated camera views in the imaging process, spatial displacements of the observed structure can be reconstructed using triangulation. In this thesis a novel, frequency-domain triangulation method is introduced. Using this approach, multiple views of the vibrating specimen no longer need to be imaged synchronously, facilitating spatial measurements using a single camera. Additionally, utilizing a known geometric model of the specimen in the imaging system calibration procedure simplifies the relation between the measurement and the numerical model of the structure under test and the selection of measurement points-of-interest. By extending the recently introduced Spectral Optical Flow Imaging method to multiple views using frequency-domain triangulation, a novel method is also introduced that enables the measurement of spatial operating deflection shapes of complex-shaped vibrating structures using a single still-frame camera.
|
