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Automation of point cloud processing to increase the deformation monitoring accuracy / Ján Erdélyi in Applied geomatics, vol 9 n° 2 (June 2017)  

Public [article]  inApplied geomatics > vol 9 n° 2 (June 2017) . - pp 105 - 113 Titre : Automation of point cloud processing to increase the deformation monitoring accuracy Type de document : Article/Communication Auteurs : Ján Erdélyi, Auteur ; Alojz Kopacik, Auteur ; Imrich Liptak, Auteur ; Peter Kyrinovič, Auteur Année de publication : 2017 Article en page(s) : pp 105 - 113 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Matlab [Termes IGN] régression [Termes IGN] semis de points [Termes IGN] surveillance d'ouvrage [Termes IGN] traitement automatique de données [Termes IGN] traitement de données localisées Résumé : (auteur) The weather conditions and the loading during operation cause changes in the shape of engineering structures that affect static and dynamic function and reliability of these structures. Due to this fact, geodetic monitoring is an integral part of engineering structure diagnostics and gives important information about the current state (condition) of the structure. Terrestrial laser scanning (TLS) is often used for data acquisition in cases, requiring 3D information with high resolution. Therefore, TLS is used in different surveying applications, even in deformation monitoring of buildings or engineering structures. TLS allows non-contact documentation of the behaviour of the monitored structure. The accuracy of determination of the 3D coordinates of single measured points by currently commercially available laser scanners is several millimetres. The precision can be increased using suitable data processing, when valid assumptions about the scanned surface are available. The paper presents the possibility of deformation monitoring using TLS. To increase the precision of the results, the chosen parts of the monitored structure are approximated by fitting planes to point cloud. In this case, the position of the monitored point (part of structure) is calculated from tens or hundreds of scanned points instead of a single measurement. An application based on software MATLAB®, Displacement_TLS, was developed for automated data processing. It takes only several minutes, as the calculation is executed automatically for all monitored points at once. The proposed method represents fast and simple data processing. Benefits of the proposed method are demonstrated by experimental measurements of different structures and building elements. Numéro de notice : A2017-360 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s12518-017-0186-y Date de publication en ligne : 19/04/2017 En ligne : http://doi.org/10.1007/s12518-017-0186-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85769 [article]

Spectral analysis of structural deformation - A case study / Alojz Kopacik in Journal of applied geodesy, vol 6 n° 3-4 (November 2012)  

Public [article]  inJournal of applied geodesy > vol 6 n° 3-4 (November 2012) . - pp 159 - 166 Titre : Spectral analysis of structural deformation - A case study Type de document : Article/Communication Auteurs : Alojz Kopacik, Auteur ; Imrich Liptak, Auteur Année de publication : 2012 Article en page(s) : pp 159 - 166 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] analyse spectrale [Termes IGN] auscultation d'ouvrage [Termes IGN] Bratislava [Termes IGN] déformation d'édifice [Termes IGN] lever tachéométrique [Termes IGN] pont [Termes IGN] surveillance d'ouvrage [Termes IGN] transformation rapide de Fourier Résumé : (Auteur) Building structures are extremely sensitive to the influence of outdoor conditions. The most frequent types of outdoor conditions are the influence of wind, sunshine, changes in the temperature of a building's surroundings and, lastly, the effect of a buildings own loading or the improper loading by another source. According to the resonance of the structure with its surroundings, vibrations and oscillations at relatively high frequency intervals (0.1–100.0 Hz) also occur. These phenomena significantly affect the static and dynamic characteristics of structures, as well as their safety and functionality. The paper provides an example of the monitoring of these phenomena using geodetic methods at two different types of structures. The first example is an industrial structure with a cylindrical shape, the monitoring of which was made by a total station with a measuring frequency of approximately 2 Hz. The second example is the Apollo Bridge on the Danube in Bratislava (Slovakia), the steel structure of which was measured by acceleration sensors with a frequency of up to 10 Hz. The central aim of the paper is an analysis of the dynamic behavior of both structures using spectral analysis methods. The use of the Fast Fourier Transform (FFT) and the Lomb–Scargle periodogram is described; the structure's own frequencies and the amplitudes of the structure's oscillations are calculated. Numéro de notice : A2012-596 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : doi.org/10.1515/jag-2012-0023 En ligne : http://www.degruyter.com/view/j/jag.2012.6.issue-3-4/jag-2012-0023/jag-2012-0023 [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32042 [article]