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Auteur Mamdouh El-Badry |
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Multi-dimensional and multi-temporal motion estimation of a beam surface during dynamic testing using low-frame rate digital cameras / I. Detchev in Applied geomatics, vol 9 n° 3 (September 2017)
[article]
Titre : Multi-dimensional and multi-temporal motion estimation of a beam surface during dynamic testing using low-frame rate digital cameras Type de document : Article/Communication Auteurs : I. Detchev, Auteur ; Derek Litchi, Auteur ; Ayman Habib, Auteur ; Mamdouh El-Badry, Auteur Année de publication : 2017 Article en page(s) : pp 127 - 141 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] ajustement de paramètres
[Termes IGN] caméra numérique
[Termes IGN] déviation de la verticale
[Termes IGN] méthode des moindres carrés
[Termes IGN] photogrammétrie métrologiqueRésumé : (Auteur) The combination of digital close-range photogrammetric systems and image processing techniques has been employed in structural health monitoring applications for more than 10 years. The use of off-the-shelf entry level digital single-lens reflex cameras has lately become a suitable choice even for applications requiring sub-millimetre- level precision especially when the involved devices need to be inexpensive. The drawback of such low-cost cameras is in the trade-off between spatial resolution, frame rate, and burst rate—at the highest available spatial resolution, a high frame rate is either not possible or it has a low burst rate. This may be problematic when monitoring a structural component during a dynamic/fatigue test. In order to estimate specimen motion in such a situation, this paper proposes an innovative sinusoidal fitting based on a least squares adjustment. This method simultaneously processes multiple bursts of data in order to synthetically increase the sampling frequency of the system. The input data for the adjustment comes from a full surface modelling procedure based on a newly proposed generalized 3D polynomial. The experimental results include a beam deformation test performed in a structures laboratory. The new sinusoidal fitting method effectively increased the system temporal resolution three-fold, which improved the precision of the derived parameters with up to two orders of magnitude. The root mean square error of the residuals were as good as 26 μm, and the one of the estimated amplitudes from the photogrammetric system versus a set of laser transducers used as control was as small as 43 μm. Numéro de notice : A2017-595 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s12518-017-0184-0 Date de publication en ligne : 10/04/2017 En ligne : https://doi.org/10.1007/s12518-017-0184-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86803
in Applied geomatics > vol 9 n° 3 (September 2017) . - pp 127 - 141[article]Structural dynamic deflection measurement with range cameras / Xiaojuan Qi in Photogrammetric record, vol 29 n° 145 (March - May 2014)
[article]
Titre : Structural dynamic deflection measurement with range cameras Type de document : Article/Communication Auteurs : Xiaojuan Qi, Auteur ; Derek D. Lichti, Auteur ; Mamdouh El-Badry, Auteur ; Ting On Chan, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 89 - 107 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] déformation d'édifice
[Termes IGN] photogrammétrie terrestre
[Termes IGN] surveillance d'ouvrage
[Termes IGN] télémétrieRésumé : (Auteur) Time-of-flight range cameras offer numerous advantages for the measurement of dynamic phenomena, thanks to their ability to directly measure three-dimensional coordinates of objects at video rates using only one sensor. This paper reports the results of an investigation into the development of a range camera based system for measuring the deflection of reinforced concrete beams subjected to cyclic fatigue loading. New data segmentation methods and reconstruction algorithms have been developed to reconstruct the time-dependent displacement of the beam with sub-millimetre amplitude and millihertz-level frequency precision and accuracy in all three dimensions along the entire beam length. Moreover, sub-millimetre changes in displacement measurements due to stiffness degradation caused by fatigue are also reported. Numéro de notice : A2014-157 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12047 Date de publication en ligne : 21/02/2014 En ligne : https://doi.org/10.1111/phor.12047 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33062
in Photogrammetric record > vol 29 n° 145 (March - May 2014) . - pp 89 - 107[article]Réservation
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