Dynamic beam deformation measurements with off-the-shelf digital cameras

Abstract

The physical health monitoring of civil infrastructure systems is an important task that must be performed frequently to ensure their serviceability and sustainability. Part of this process requires fine-scale monitoring of the structural elements that form the infrastructure system. This has traditionally been done with instrumentation, which either requires contact/access to the structural element, performs deformation measurements in only one dimension, or both. In order to avoid the downsides of the commonly used instrumentation systems, this paper proposes the use of a remote sensing approach based on a three dimensional photogrammetric system. The proposed system is low-cost, consists of off-the-shelf components, and is capable of targetless reconstruction. Also, based on the given configuration and the implemented processing techniques, the system yields deformation measurements well below the submillimetre level.

An artistic, mythological and documentary study of the Atargatis panel from et-Tannur, Jordan

“…The need to provide high quality 3D modelling of the heritage sites and objects has stimulated further research in the field of photogrammetry and computer vision. 44 Photogrammetry is based on a 3D data collection from multiple images. The geometry is created by identifying sets of common points from two or more source images.…”

Structural Dynamic Deflection Measurement With Range Cameras

“…Four measurement systems were used: a range camera system comprising three SR4000 devices; an eight‐camera and a two‐projector digital photogrammetric system (Detchev et al., , ); a single Microsoft (MS) Kinect sensor; and five Keyence LK‐G407 CCD LDSs (Keyence, ). The three optical sensor systems were rigidly mounted to a rigid steel scaffold frame approximately 1·9 m above the top of the concrete beam with a nadir‐looking orientation.…”

“…Over 36 000 load cycles were applied from 24 to 96 kN causing 4 mm displacement amplitude (8 mm peak‐to‐peak displacement) at the beam's mid‐span in Experiment I, and from 24 to 72 kN producing 2·6 mm displacement amplitude at the mid‐span in Experiment II. In both experiments the fatigue loading cycles were applied at two different frequencies: 1 Hz to match the sampling frequency capability of the low‐cost digital camera system (Detchev et al., , ); and 3 Hz, which simulates the common traffic load frequency on bridges (Papakonstantinou et al., ; Heffernan and Erki, ).…”

“…Detchev et al. (; ) report a photogrammetric system comprising multiple off‐the‐shelf digital cameras and projectors for both static and dynamic load test measurement. However, the cameras' low frame acquisition rate limits the loading frequency that can be measured to 1 Hz, whereas 3 Hz is normally required (Papakonstantinou et al., ; Heffernan and Erki, ).…”

Vertical Dynamic Deflection Measurement in Concrete Beams with the Microsoft Kinect

“…Laser scanning systems are, however, best suited for the measurement of displacements under static loading conditions due to their sequential data capture. Though Detchev et al [ 16 ] demonstrate a digital photogrammetric system for both static and dynamic load test measurement—their experiments were conducted concurrently as those reported herein—the cameras' low acquisition rate limits the loading frequency that can be measured to 1 Hz, whereas 3 Hz is normally required [ 17 , 18 ].…”