A Low-Cost Robotic Camera System for Accurate Collection of Structural Response

Abstract

Vision-based technologies are becoming ubiquitous when considering sensing systems for measuring the response of structures. Availability of proprietary camera systems has opened up the scope for many bridge monitoring projects. Even though structural response can be measured at high accuracies when analyzing target motions, the main limitations to achieving even better results are camera costs and image resolution. Conventional camera systems capture either the entire structure or large/small part of it. This study introduces a low-cost robotic camera system (RCS) for accurate measurement collection of structural response. The RCS automatically captures images of parts of a structure under loading, therefore, (i) giving a higher pixel density than conventional cameras capturing the entire structure, thus allowing for greater measurement accuracy, and (ii) capturing multiple parts of the structure. The proposed camera system consists of a modified action camera with a zoom lens, a robotic mechanism for camera rotation, and open-source software which enables wireless communication. A data processing strategy, together with image processing techniques, is introduced and explained. A laboratory beam subjected to static loading serves to evaluate the performance of the RCS. The response of the beam is also monitored with contact sensors and calculated from images captured with a smartphone. The RCS provides accurate response measurements. Such camera systems could be employed for long-term bridge monitoring, in which strains are collected at strategic locations, and response time-histories are formed for further analysis.

Bolt-Loosening Monitoring Framework Using an Image-Based Deep Learning and Graphical Model

“…Recent research has focused on developing more advanced and low-cost vision-based techniques for on-site applications with complicated conditions. For examples, Kromanis and Forbes [ 21 ] introduced a low-cost robotic camera system which allows collecting high pixel density for the accurate measurement of structural responses; other researchers have developed smartphone-based monitoring systems to measure structural deformation with an inexpensive cost [ 22 ].…”

Experiment of Structural Geometric Morphology Monitoring for Bridges Using Holographic Visual Sensor

“…To summarize, contact health monitoring sensors or non-contact sensors are primarily used in the existing literature about SHM theories and methods to identify static or dynamic characteristic parameters of structures; and, in combination with finite element analysis (FEA) and experimental analysis, structural damage identification and working status estimation are performed based on measured responses of the structure, so as to reveal whole-process static/dynamic behavior, mechanisms and evolutionary rules of the structure under actions of complex loads and environmental coupling. Thanks to definite physical meanings, these approaches have been employed in practical projects [18][19][20][21][22][23][24][25][26][27][28][29]. However, they remain very vulnerable to limitations of corresponding technical conditions.…”

“…Regarding structural geometric deformation monitoring, it is both a key component of health monitoring in the field of bridge engineering [20][21][22][23][24][25][26][27][28][29] and a critical index of structural behavior evaluation for bridges. To a certain extent, anomalous changes in structural geometry give embodiments to present safety status of bridges in a real sense; and, different degrees of structural damages or defects in long-term service time are also embodied in such anomalous changes.…”

“…To a certain extent, anomalous changes in structural geometry give embodiments to present safety status of bridges in a real sense; and, different degrees of structural damages or defects in long-term service time are also embodied in such anomalous changes. As for structural geometric deformation monitoring of long-span bridges [23][24][25][26][27][28][29] and in order to monitor mechanical parameters of and environmental effects on bridges, a limited number of contact sensors should be arranged on key monitoring points of the bridge structure to form a sensor array on one hand; and, on the other hand, a health monitoring system should be established by integrating them with other monitoring sensors. Alternatively, manual inspections are regularly carried out for control points of the bridge area monitoring by a total station, a level gauge and a theodolite.…”

An Overall Deformation Monitoring Method of Structure Based on Tracking Deformation Contour

“…The majority studies have still been focused on measurements of small-scale laboratory structures or field measurements of large structures at a limited number of points for a short period of time. Rolands Kromanis et al [9] introduces a low-cost robotic camera system (RCS) for accurate measurement collection of structural response. The low-cost RCS provides very accurate vertical displacements.…”