Dynamic Deformation Measurement by the Sampling Moiré Method from Video Recording and its Application to Bridge Engineering

Ri, Shien; Tsuda, Hiroshi; Chang, Kuang‐An; Hsu, Shu-Kang; Lo, Feng Hsiang; Lee, T.

doi:10.1007/s40799-019-00358-4

Cited by 19 publications

(12 citation statements)

References 21 publications

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“…For geometric feature, some scholars have proposed deflection measurement method based on sampling Moiré pattern. 32,33 Gray feature has certain requirements on the gray information of the measured target surface. The most representative technology using gray feature is the digital image correlation (DIC) technology, which has the advantages of subpixel displacement positioning and high accuracy.…”

Section: Feature Detection and Matchingmentioning

confidence: 99%

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Measurement method and recent progress of vision-based deflection measurement of bridges: a technical review

et al. 2022

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The deflection that can reflect the vertical stiffness of a bridge plays an important role in the structural evaluation and health monitoring of bridges. In the past 20 years, the bridge deflection measurement methods based on computer vision and photogrammetry have been gradually applied to the field measurement due to the advantages of noncontact measurement, simple experimental setup, and easy installation. The technical research progress of vision-based bridge deflection measurement is reported from four aspects: basic principles, measurement methods, influencing factors, and applications. Basic principles mainly include camera calibration, three-dimensional (3D) stereo vision, photogrammetry, feature detection, and matching. For measurement methods, the single-camera two-dimensional measurement, the dual-camera 3D measurement, the quasistatic measurement based on photogrammetry, the multipoint dynamic measurement based on the displacement-relay videometrics and the deflection measurement based on UAV platform are introduced, respectively. In the section of influencing factors, this part summarizes the work of many researchers on the effects of camera imaging factors, calibration factors, algorithm factors, and environmental factors on measurement results. The field measurement results at different measurement distances and measurement accuracy based on these are presented in terms of applications. Finally, the future development trends of vision-based bridge deflection measurement are expected.

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Section: Feature Detection and Matchingmentioning

confidence: 99%

“…The displacement information can be further used to evaluate the deflection. 32 Using 2D grids, the displacement of the research object can be measured in two directions simultaneously. With the help of high-speed cameras, dynamic displacement curves over time can be obtained by this method.…”

Section: Feature Detection and Matching Based On Geometric Featurementioning

confidence: 99%

Measurement method and recent progress of vision-based deflection measurement of bridges: a technical review

et al. 2022

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“…This method uses a charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) sensor to capture a single image of a specimen grating of known pitch during deformation. Only one image is handled to evaluate the phase distribution by generating multiple phase-shifted moiré patterns by the thinning-out, down-sampling, and interpolation of the sequential pixels through phase analysis [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Through the phase difference of the moiré fringe prior to deformation to that of post-deformation, the displacement distribution is attained.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, this has been expanded to the displacement measurement of a concrete bridge for a high-speed railway in Japan using retroreflective moiré markers. The two-dimensional (2-D) in-plane displacements at multiple locations could be easily measured from recorded digital images [11], even for the measurement of the deflection and vibration of a large-scale concrete bridge from captured video with a commercial cinema camera [12] in recent times. Further, in terms of experiments, comparative experiments conducted in a columnar cantilever beam connected to a loading jack and laser displacement meter demonstrated the effectiveness of the method for deformation measurement when the errors between the measurements were compared [14,21].…”

Section: Introductionmentioning

confidence: 99%

CCTV Camera Array for the Displacement and Strain Measurement of a Beam Specimen in a Laboratory

2022

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The available conventional sensors, like displacement transducers, used in the Structural Engineering Laboratory are expensive. In addition to that, the need for data acquisition devices also escalates the expense invested in point contact measurement systems. The recent appeal of vision-based measurement and the search for cost-effectiveness has led to an exploration of the established sampling moiré method using cheap closed-circuit television (CCTV) cameras as a viable option. The sampling moiré method is simple and analyzes the displacements from grating images by a phase-shifting method. Several trial experiments were conducted, which demonstrated that the setup is at least as accurate as the traditional measuring system. An experiment was conducted on a steel I-beam for displacement measurement, which displayed satisfactory results. In addition, the setup was also tested for strain measurement, and it has yielded promising results that need fine-tuning. This paper discusses the challenges, findings, and the possibility of incorporating vision-based displacement measurements in laboratory platforms.

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“…In vibration-based SHM, the latest study by Ri et al [73] used downsized image data from a bridge-field experiment. The study demonstrated that JPEG image quality of 20% was the threshold to balance between an effective compression and the measurement accuracy.…”

Section: Introductionmentioning

confidence: 99%

Implementation and Evaluation of Vision-Based Sensor Image Compression for Close-Range Photogrammetry and Structural Health Monitoring

Ngeljaratan

Moustafa

2020

Sensors

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Much research is still underway to achieve long-term and real-time monitoring using data from vision-based sensors. A major challenge is handling and processing enormous amount of data and images for either image storage, data transfer, or image analysis. To help address this challenge, this study explores and proposes image compression techniques using non-adaptive linear interpolation and wavelet transform algorithms. The effect and implication of image compression are investigated in the close-range photogrammetry as well as in realistic structural health monitoring applications. For this purpose, images and results from three different laboratory experiments and three different structures are utilized. The first experiment uses optical targets attached to a sliding bar that is displaced by a standard one-inch steel block. The effect of image compression in the photogrammetry is discussed and the monitoring accuracy is assessed by comparing the one-inch value with the measurement from the optical targets. The second application is a continuous static test of a small-scale rigid structure, and the last application is from a seismic shake table test of a full-scale 3-story building tested at E-Defense in Japan. These tests aimed at assessing the static and dynamic response measurement accuracy of vision-based sensors when images are highly compressed. The results show successful and promising application of image compression for photogrammetry and structural health monitoring. The study also identifies best methods and algorithms where effective compression ratios up to 20 times, with respect to original data size, can be applied and still maintain displacement measurement accuracy.

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Dynamic Deformation Measurement by the Sampling Moiré Method from Video Recording and its Application to Bridge Engineering

Cited by 19 publications

References 21 publications

Measurement method and recent progress of vision-based deflection measurement of bridges: a technical review

Measurement method and recent progress of vision-based deflection measurement of bridges: a technical review

CCTV Camera Array for the Displacement and Strain Measurement of a Beam Specimen in a Laboratory

Implementation and Evaluation of Vision-Based Sensor Image Compression for Close-Range Photogrammetry and Structural Health Monitoring

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