Tri-Camera High-Speed Videogrammetry for Three-Dimensional Measurement of Laminated Rubber Bearings Based on the Large-Scale Shaking Table

Abstract

Laminated rubber bearings are widely used for the mitigation of seismic damage of large-scale structures and equipment. However, owing to the flexibility in horizontal direction, the traditional contacted transducer is difficult to acquire the displacement data accurately in the three directions, respectively. In this paper, three-dimensional displacement measurement of laminated rubber bearing based on the large-scale shaking table is achieved by the use of a tri-camera high-speed videogrammetric system consisting of three complementary-metal-oxide-semiconductor (CMOS) cameras, one synchronous controller, and one pair of 1000 watt light sources, which are used to simultaneously acquire the tri-camera image sequences of laminated rubber bearing at a speed of 300 frames per second (fps). Firstly, this paper proposes a fast image block technique for detecting and tracking targets in tri-camera image sequences by integration of techniques morphological edge detection, attribute based ellipse extraction and least-squares-based fitting adjustment. Secondly, this paper presents an integrated bundle adjustment approach, which brings continuous tracking points into one collinearity condition equation, to reconstruct the three dimensional coordinates of continuous tracking points, for the purpose of improving the accuracy of three-dimensional coordinates of tracking points based on tri-camera image sequences. At last, an empirical experiment was conducted to measure the three-dimensional displacement of laminated rubber bearings on the shaking table by the use of the proposed method. The experimental results showed that the proposed method could obtain three-dimensional displacement of laminated rubber bearings with an accuracy of more than 0.5 mm.

Photogrammetric Solution for Analysis of Out-Of-Plane Movements of a Masonry Structure in a Large-Scale Laboratory Experiment

“…This method was chosen since the wall being tested lacked the texture (Figure 2a) to carry out either the photogrammetric approach based on digital image correlation or the structure from motion strategy. To this end, a similar strategy as proposed by Tong et al [24,25] was used, in which an edge detection algorithm was used to estimate the edges of the targets, followed by a minimization strategy based on the Levenberg-Marquardt method, to estimate the center of the targets. Instead of using a morphological edge detector, our strategy employs state-of-the-art edge detectors based on the partial area effect proposed by Trujillo et al [36].…”

“…In addition to this, its flexibility makes it possible to evaluate the deformation suffered by different engineering solutions, from small scales (e.g., mechanical tests) [16,[21][22][23]] to large structures [7,14,15,20]. This property of the ability to capture several images per second makes it possible to use this technology in dynamic scenarios (e.g., shaking table tests) [7,14,17,20,[24][25][26][27]. Within this discipline, there are three strategies that are commonly applied in order to evaluate the changes that occur during a scenario: (i) digital image correlation method (DIC) [10][11][12]16]; (ii) structure from motion approach using change detection algorithms (i.e., cloud-to-cloud comparison algorithms) [15,[28][29][30]; and (iii) point-tracking approaches [14,20,23,25,26,31].…”

High-speed videogrammetric measurement of the displacement of suspendome structure node

“…Videogrammetry is one such method that utilizes two or more high-speed industrial cameras placed at different positions to monitor fast-moving objects simultaneously. Through captured image sequences, videogrammetry can accurately calculate the three-dimensional (3D) spatial coordinates of the measured object in each epoch [7]. Prior studies have demonstrated the ability of videogrammetry to achieve sub-millimetre accuracy.…”

Indirect Measurement of Loading Forces with High-Speed Camera

“…Vision-based methods are becoming crucial in the non-contact measurement of displacement and velocities of engineering structures [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. However, the use of special high-speed imaging technology is necessary if the dynamic response contains high frequencies, which cameras cannot correctly capture with standard frame rates.…”

“…A Phantom high-speed camera with a maximal frame rate of 12,800 fps was used in the investigation. Tong et al [ 15 ] described a videogrammetry method for three-dimensional vibrations reconstruction of a structure excited on a large-sized shaking table. The tests were carried out to examine the behavior of laminated rubber bearings used to mitigate seismic damage.…”