Conception and development of an optical methodology applied to long-distance measurement of suspension bridges dynamic displacement

Martins, L. Lages; Rebordão, J.; Ribeiro, A.

doi:10.1088/1742-6596/459/1/012055

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…In recent years, with the increasing development of computer vision technology and image acquisition equipment, computer vision-based structural monitoring methods have been used in bridge deformation monitoring [6], structural displacement measurement [7,8], cable vibration [9], fan blade vibration [10], and so on.…”

Section: Introductionmentioning

confidence: 99%

Vision‐Based Dynamic Displacement Measurement of Isolation Bearing

Dang

2022

Advances in Civil Engineering

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The existing computer vision-based structural displacement measurement method can only obtain structural displacement when the camera is fixed or the pose of the camera is known at all times. However, the aforementioned conditions cannot be met when an earthquake occurs. Therefore, this study presents a method to achieve a dynamic displacement measure of an isolated bearing from a video without the known camera motion: two cameras are set up along the horizontal orthogonal direction, and circular targets are set at the upper and lower connecting plates of the isolation bearing. A combination of HSV color space, Canny edge detection, and Hough transform circle detection is used to obtain the dynamic displacement of the isolation bearing. This task is done by measuring the relative displacement between the upper and lower target points. A basic mechanical performance test of LRB500 isolation bearing is used to verify the proposed method. The result shows that the horizontal displacement time history of the isolation bearing obtained by this method is almost the same as the result obtained by the displacement meter whether the camera is moving or fixed. However, compared with the results measured by the displacement meter, the absolute error of the peak horizontal and vertical displacements are both less than 1 mm, which indicates that the proposed method can be used in displacement monitoring under long-term load and earthquake action of isolation bearing.

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Section: Introductionmentioning

confidence: 99%

Vision‐Based Dynamic Displacement Measurement of Isolation Bearing

Dang

2022

Advances in Civil Engineering

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“…Meanwhile, Ho et al (2012) proposed an infrastructure dynamic displacement measurement method based on multipoint vision. Moreover, Martins et al (2013) proposed the use of visual technology to measure the three-dimensional displacement of suspension bridges. Based on correlation theory of digital image processing and a multipoint template matching algorithm, Ye et al (2013Ye et al ( , 2016a proposed a computer vision-based longdistance noncontact distributed structural displacement monitoring method for long-span bridges, which realized the onsite structural displacement monitoring of distance in kilometers.…”

Section: Introductionmentioning

confidence: 99%

Novel Approach to Extract Dense Full-Field Dynamic Parameters of Large-Scale Bridges Using Spatial Sequence Video

Deng

Zhou

Shao

et al. 2021

Journal of Civil Engineering and Management

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This study proposes the use of a high-speed camera as a holographic visual sensor to obtain the dense full-field dynamic parameters of the main beam of a bridge by the field of view through uniaxial rotation photography. Based on the basic principle that the frequency and mode of a structure are inherent characteristics, the mode coordinates obtained from each field of view are unified, normalized, and matched according to the same name pixels to obtain the dense fullfield dynamic parameters of the entire bridge. The frequency and first three order modes of a self-anchored suspension test bridge are collected by the method proposed in this study. The frequency comparison between the accelerometers and dial gauges is within 3%, and the mode shapes are more holographic and more realistic than those obtained by limited measuring points. In addition, the difference in the curvature mode under various damage conditions obtained by limited measurement points is compared with that obtained by the method proposed in this study. Results shows that the dense full-field modal curvature difference can reflect the change in the damage location even in a low order, which means the sensitivity of the change of damage location in low-order modal.

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“…Elgemal et al [22] included computer vision in an integrated system to create a ''decision support system'' for bridges and other lifelines. It is good to note that recently several studies have been conducted to address the issue of measuring displacement of civil structures using videos cameras [23][24][25][26][27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

“…Our methodology is based on the original idea presented in [33] and further applied in [34]. The essence of the original idea is that single pixels can carry essential information about minute changes of objects that are not visible to the naked eye, but can be made visible by a technique called Eulerian motion magnification [24]. In our work we have showed, experimentally, that change of intensity in certain pixels of a digital video can be related to the natural frequency of a vibrating structure.…”

Section: Introductionmentioning

confidence: 99%

Eulerian-based virtual visual sensors to detect natural frequencies of structures

Shariati

Schumacher

Ramanna

2015

J Civil Struct Health Monit

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Natural frequency of vibration data are often used to study the behavior of structures. They are also used to calibrate finite element models and some studies have proposed that the presence and location of damage can be estimated using these data. Along this line, we earlier proposed the concept of Eulerian-based virtual visual sensors to estimate natural frequencies of structural vibrations based on the change of pixel intensity captured in a digital video. Benefits of this approach are that it allows for distributed sensing and is contactless. However, as intensity does not reflect any physical quantity, such as displacement, and the range of values is difficult to control, the signal-to-noise ratio (SNR) can be relatively low. Furthermore, impulsive changes of intensity caused by large deformations compared to the pixel size can result in an impulse train in the frequency domain which leads to ambiguity in determining peak frequencies. As a result, it is often only possible to estimate the first fundamental mode of vibration. In this paper, we present strategies using targets mounted to the structure combined with signal processing methods that significantly improve the SNR and allow for detecting higher natural frequencies of vibration. The concepts, their mathematical background, laboratory tests to prove the accuracy and enhancement of SNR, as well as an example of an in-service pedestrian bridge are presented and discussed.

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Conception and development of an optical methodology applied to long-distance measurement of suspension bridges dynamic displacement

Cited by 6 publications

References 8 publications

Vision‐Based Dynamic Displacement Measurement of Isolation Bearing

Vision‐Based Dynamic Displacement Measurement of Isolation Bearing

Novel Approach to Extract Dense Full-Field Dynamic Parameters of Large-Scale Bridges Using Spatial Sequence Video

Eulerian-based virtual visual sensors to detect natural frequencies of structures

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