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A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment

Computer vision-based approaches are very useful for dynamic displacement measurement, damage detection, and structural health monitoring. However, for the application using a large number of existing cameras in buildings, the computational cost of videos from dozens of cameras using a centralized c...

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Autores principales: Hsu, Ting-Yu, Kuo, Xiang-Ju
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7349837/
https://www.ncbi.nlm.nih.gov/pubmed/32549260
http://dx.doi.org/10.3390/s20123374
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author Hsu, Ting-Yu
Kuo, Xiang-Ju
author_facet Hsu, Ting-Yu
Kuo, Xiang-Ju
author_sort Hsu, Ting-Yu
collection PubMed
description Computer vision-based approaches are very useful for dynamic displacement measurement, damage detection, and structural health monitoring. However, for the application using a large number of existing cameras in buildings, the computational cost of videos from dozens of cameras using a centralized computer becomes a huge burden. Moreover, when a manual process is required for processing the videos, prompt safety assessment of tens of thousands of buildings after a catastrophic earthquake striking a megacity becomes very challenging. Therefore, a decentralized and fully automatic computer vision-based approach for prompt building safety assessment and decision-making is desired for practical applications. In this study, a prototype of a novel stand-alone smart camera system for measuring interstory drifts was developed. The proposed system is composed of a single camera, a single-board computer, and two accelerometers with a microcontroller unit. The system is capable of compensating for rotational effects of the camera during earthquake excitations. Furthermore, by fusing the camera-based interstory drifts with the accelerometer-based ones, the interstory drifts can be measured accurately even when residual interstory drifts exist. Algorithms used to compensate for the camera’s rotational effects, algorithms used to track the movement of three targets within three regions of interest, artificial neural networks used to convert the interstory drifts to engineering units, and some necessary signal processing algorithms, including interpolation, cross-correlation, and filtering algorithms, were embedded in the smart camera system. As a result, online processing of the video data and acceleration data using decentralized computational resources is achieved in each individual smart camera system to obtain interstory drifts. Using the maximum interstory drifts measured during an earthquake, the safety of a building can be assessed right after the earthquake excitation. We validated the feasibility of the prototype of the proposed smart camera system through the use of large-scale shaking table tests of a steel building. The results show that the proposed smart camera system had very promising results in terms of assessing the safety of steel building specimens after earthquake excitations.
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spelling pubmed-73498372020-07-15 A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment Hsu, Ting-Yu Kuo, Xiang-Ju Sensors (Basel) Article Computer vision-based approaches are very useful for dynamic displacement measurement, damage detection, and structural health monitoring. However, for the application using a large number of existing cameras in buildings, the computational cost of videos from dozens of cameras using a centralized computer becomes a huge burden. Moreover, when a manual process is required for processing the videos, prompt safety assessment of tens of thousands of buildings after a catastrophic earthquake striking a megacity becomes very challenging. Therefore, a decentralized and fully automatic computer vision-based approach for prompt building safety assessment and decision-making is desired for practical applications. In this study, a prototype of a novel stand-alone smart camera system for measuring interstory drifts was developed. The proposed system is composed of a single camera, a single-board computer, and two accelerometers with a microcontroller unit. The system is capable of compensating for rotational effects of the camera during earthquake excitations. Furthermore, by fusing the camera-based interstory drifts with the accelerometer-based ones, the interstory drifts can be measured accurately even when residual interstory drifts exist. Algorithms used to compensate for the camera’s rotational effects, algorithms used to track the movement of three targets within three regions of interest, artificial neural networks used to convert the interstory drifts to engineering units, and some necessary signal processing algorithms, including interpolation, cross-correlation, and filtering algorithms, were embedded in the smart camera system. As a result, online processing of the video data and acceleration data using decentralized computational resources is achieved in each individual smart camera system to obtain interstory drifts. Using the maximum interstory drifts measured during an earthquake, the safety of a building can be assessed right after the earthquake excitation. We validated the feasibility of the prototype of the proposed smart camera system through the use of large-scale shaking table tests of a steel building. The results show that the proposed smart camera system had very promising results in terms of assessing the safety of steel building specimens after earthquake excitations. MDPI 2020-06-15 /pmc/articles/PMC7349837/ /pubmed/32549260 http://dx.doi.org/10.3390/s20123374 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Hsu, Ting-Yu
Kuo, Xiang-Ju
A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title_full A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title_fullStr A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title_full_unstemmed A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title_short A Stand-Alone Smart Camera System for Online Post-Earthquake Building Safety Assessment
title_sort stand-alone smart camera system for online post-earthquake building safety assessment
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7349837/
https://www.ncbi.nlm.nih.gov/pubmed/32549260
http://dx.doi.org/10.3390/s20123374
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