DIGITAL IMAGE PROCESSING FOR A MULTIPOINT 2D DISPLACEMENT MEASUREMENT SYSTEM IN STRUCTURAL MODELS

Isuhuaylas S.; Diaz M.; Inocente I.; Guizado E.; Zavala C.; Lopez L.; Jaramillo J. · World Conference on Earthquake Engineering proceedings (2024)

Resumen

Extensive research has been conducted on computer vision-based techniques and digital image processing to accurately measure displacements and deformations for structural health monitoring (SHM). The collective efforts of researchers have facilitated the implementation of displacement measurement systems based on these techniques and proposed various applications. In this context, the present paper introduces a measurement system using video cameras, focusing on two-dimensional and multipoint detection because systems with these characteristics and their potential applications have received less attention. The system’s validity was tested by measuring the displacements of a shaking table. The measurements obtained were compared with those derived from traditional methods and instruments, such as laser and double integration of acceleration sensor records, using the normalized root mean square error (NRMSE) and their peak responses were compared. The results demonstrated the accuracy of the computer vision-based system, and two-dimensional and multiple-point measurements were simultaneously achieved, eliminating the need to install an independent sensor for each point. As an application, the system was implemented to perform dynamic tests on a shaking table to detect torsional irregularities in structural models and monitor their structural health. By recording a top-down view of the structure, two-dimensional displacements at key points can be obtained, allowing the assessment of the emergence of torsional irregularities. In addition, the direct measurement of displacements allows for a more detailed observation of the inelastic behavior of the structure through residual displacement, hysteresis curves, and capacity curves.

Instituciones: Universidad Nacional de Ingeniería