Monitoring 3D vibrations in structures using high resolution blurred imagery

Photogrammetry has been used in the past to monitor the laboratory testing of civil engineering structures using multiple image based sensors. This has been successful, but detecting vibrations during dynamic structural tests has proved more challenging. Detecting vibrations during dynamic structural tests usually depend on high speed cameras, but these sensors often result in lower image resolutions and reduced accuracy. To overcome this limitation, a novel approach described in this paper has been devised to take measurements from blurred images in long-exposure photos. The motion of the structure is captured in individual motion-blurred image, without dependence on imaging speed. A bespoke algorithm then determines each measurement point’s motion. Using photogrammetric techniques, a model structure’s motion with respect to different excitation frequencies is captured and its vibration envelope recreated in 3D. The approach is tested and used to identify changes in the model’s vibration response.