New Bridge Inspection Approach with Joint UAV and DIC System

Abstract

This research aims to develop a new bridge inspection approach using unmanned aerial vehicle (UAV) coupled with digital image correlation (DIC) system. The DIC system incorporating UAV images can measure displacements or strains by analyzing patterns of reference and deformed images. As part of this research, a commercially available UAV, DJI Matrice 210, was integrated with the DIC system using a 3D printed mounting plate, and the joint UAV-DIC system was utilized to inspect a timber bridge girder in the Structure Lab. Then, the UAV-DIC system inspected an existing timber slab bridge in Pipestone, Minnesota, but the system was not able to efficiently identify critical damage due to its instability caused by windy conditions. Therefore, only the UAV equipped with a gimbal camera was operated to perform the bridge inspection. A significant number of images from the UAV were used and analyzed through a conventional image analysis algorithm within ImageJ software for damage quantification. The major conclusion from this research was that the UAV-DIC system was only able to detect and quantify damage (i.e., crack) on the considered girder under almost zero ambient wind conditions, and the UAV integrated with the image analysis algorithm was capable of damage identification and quantification for the inspected bridge.

UAV-based inspection of bridge and tunnel structures: an application review

“…Another emerging imaging-based application with UAVs is the displacement/deformation measurement techniques of bridge structure, e.g., photogrammetric computer vision [9], [83], [89], [97], [146] and digital image correlation (DIC) [79], [92]- [95], [148]. Despite these imaging-based techniques, it is also worth mentioning the use of Laser Doppler Vibrometers (LDV) in UAVs as a non-contact sensor to measure bridge displacements [84]- [86].…”

Grayscale Drone Inspection Image Enhancement Framework for Advanced Bridge Defect Measurement

“…Most importantly, the safety of rope access inspectors is uncertain (1). To resolve these issues, bridge inspections using drones have been frequently adopted by many researchers (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Particularly, drones can provide easier accessibility and straightforward maneuverability to the inspectors to record a high volume of videos and images for visual defect detection of a bridge.…”

“…Although the drone-enabled inspection is a useful approach to identify the defects, the inherent limitation of the image analysis may impede the accurate quantification of the defects because of inaccurate and insufficient defect boundary information. Many studies have suggested various image processing techniques including pixel-based measurement (15), pattern recognition (16)(17)(18), and digital image correlation (7,(19)(20)(21). Especially, defect measurement using the pixel-based measurement technique (15) is regarded as a commonly used suitable technique to quantify specific defects such as spalling, efflorescence, and discoloration.…”