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3D reconstruction of internal wood decay using photogrammetry and sonic tomography / Junjie Zhang in Photogrammetric record, vol 35 n° 171 (September 2020)  

Public [article]  inPhotogrammetric record > vol 35 n° 171 (September 2020) . - pp 357-374 Titre : 3D reconstruction of internal wood decay using photogrammetry and sonic tomography Type de document : Article/Communication Auteurs : Junjie Zhang, Auteur ; Kourosh Khoshelham, Auteur Année de publication : 2020 Article en page(s) : pp 357-374 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes descripteurs IGN] dépérissement [Termes descripteurs IGN] hauteur des arbres [Termes descripteurs IGN] interpolation spatiale [Termes descripteurs IGN] onde acoustique [Termes descripteurs IGN] qualité du bois [Termes descripteurs IGN] reconstruction 3D [Termes descripteurs IGN] temps de vol [Termes descripteurs IGN] tomographie [Termes descripteurs IGN] tronc [Termes descripteurs IGN] visualisation 3D Résumé : (Auteur) Knowledge of deteriorations within tree trunks is critical for arborists to conduct individual tree health assessments. Sonic tree tomography, a non‐destructive technique using sound waves, has been widely used to estimate the size and shape of internal decay based on sound wave velocity variations. However, it has commonly been applied to 2D horizontal or vertical cross sections and its accuracy is questionable due to the poor approximation of the shape of the cross section. This paper proposes an integration of close‐range photogrammetry and sonic tomography to enable accurate reconstruction of the exterior and interior of the tree trunk in 3D. The internal wood quality is represented by the spatially interpolated sound wave velocities, using the time of flight of the sound waves and the coordinates of the acoustic sensors obtained from the photogrammetric model. Experimental results show that the proposed approach provides a realistic 3D visualisation of the size, shape and location of the internal deteriorations. Numéro de notice : A2020-436 Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/phor.12328 date de publication en ligne : 06/08/2020 En ligne : https://doi.org/10.1111/phor.12328 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95842 [article]

An improved constrained simultaneous iterative reconstruction technique for ionospheric tomography / Yi Bin Yao in GPS solutions, Vol 24 n° 3 (July 2020)  

Public [article]  inGPS solutions > Vol 24 n° 3 (July 2020) Titre : An improved constrained simultaneous iterative reconstruction technique for ionospheric tomography Type de document : Article/Communication Auteurs : Yi Bin Yao, Auteur ; Changzhi Zhai, Auteur ; Jian Kong, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] interpolation [Termes descripteurs IGN] modèle ionosphérique [Termes descripteurs IGN] reconstruction 3D [Termes descripteurs IGN] teneur totale en électrons [Termes descripteurs IGN] tomographie [Termes descripteurs IGN] voxel Résumé : (auteur) Global Navigation Satellite System (GNSS) is now widely used for continuous ionospheric observations. Three-dimensional computerized ionospheric tomography (3DCIT) is an important tool for the reconstruction of electron density distributions in the ionosphere through effective use of the GNSS data. More specifically, the 3DCIT technique is able to resolve the three-dimensional electron density distributions over the reconstructed area based on the GNSS slant total electron content (STEC) observations. We present an Improved Constrained Simultaneous Iterative Reconstruction Technique (ICSIRT) algorithm that differs from the traditional ionospheric tomography methods in 3 ways. First, the ICSIRT computes the electron density corrections based on the product of the intercept and electron density within voxels so that the assignment of corrections at different heights becomes more reasonable. Second, an Inverse Distance Weighted (IDW) interpolation is used to restrict the electron density values in the voxels not traversed by GNSS rays, thereby ensuring the smoothness of the reconstructed region. Also, to improve the reconstruction accuracy around the HmF2 (the peak height of the F2 layer) altitude, a multiresolution grid is adopted in the vertical direction, with a 10-km resolution from 200 to 420 km and a 50-km resolution at other altitudes. The new algorithm has been applied to the GNSS data over the European and North American regions in different case studies that involve different seasonal conditions as well as a major storm. In the European region experiment, reconstruction results show that the new ICSIRT algorithm can effectively improve the reconstruction of the GNSS data. The electron density profiles retrieved from ICSIRT are much closer to the ionosonde observations than those from its predecessor, namely, the Constrained Simultaneous Iteration Reconstruction Technique (CSIRT). The reconstruction accuracy is significantly improved. In the North American region experiment, the electron density profiles in ICSIRT results show better agreement with incoherent scatter radar observations than CSIRT, even for the topside profiles. Numéro de notice : A2020-227 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-00981-4 date de publication en ligne : 18/04/2020 En ligne : https://doi.org/10.1007/s10291-020-00981-4 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94958 [article]

Bayesian iterative reconstruction methods for 3D X-ray Computed Tomography / Camille Chapdelaine (2019)  

Public Titre : Bayesian iterative reconstruction methods for 3D X-ray Computed Tomography Type de document : Thèse/HDR Auteurs : Camille Chapdelaine, Auteur ; Charles Soussen, Directeur de thèse Editeur : Paris-Orsay : Université de Paris 11 Paris-Sud Centre d'Orsay Année de publication : 2019 Importance : 185 p. Format : 21 x 30 cm Note générale : Bibliographie Thèse de Doctorat de l’Université Paris - Saclay préparée à l'Université Paris-Sud, Sciences et Technologies de l’Information et de la Communication (STIC), Spécialité Traitement du signal et des images Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes descripteurs IGN] artefact [Termes descripteurs IGN] capteur-projecteur [Termes descripteurs IGN] faisceau [Termes descripteurs IGN] inférence [Termes descripteurs IGN] itération [Termes descripteurs IGN] processeur graphique [Termes descripteurs IGN] rayon X [Termes descripteurs IGN] reconstruction 3D [Termes descripteurs IGN] reconstruction d'image [Termes descripteurs IGN] segmentation [Termes descripteurs IGN] spectroscopie [Termes descripteurs IGN] théorème de Bayes [Termes descripteurs IGN] tomographie [Termes descripteurs IGN] volume (grandeur) Index. décimale : THESE Thèses et HDR Résumé : (auteur) In industry, 3D X-ray Computed Tomography aims at virtually imaging a volume in order to inspect its interior. The virtual volume is obtained thanks to a reconstruction algorithm based on projections of X-rays sent through the industrial part to inspect. In order to compensate uncertainties in the projections such as scattering or beam-hardening, which are cause of many artifacts in conventional filtered backprojection methods, iterative reconstruction methods bring further information by enforcing a prior model on the volume to reconstruct, and actually enhance the reconstruction quality. In this context, this thesis proposes new iterative reconstruction methods for the inspection of aeronautical parts made by SAFRAN group. In order to alleviate the computational cost due to repeated projection and backprojection operations which model the acquisition process, iterative reconstruction methods can take benefit from the use of high-parallel computing on Graphical Processor Unit (GPU). In this thesis, the implementation on GPU of several pairs of projector and backprojector is detailed. In particular, a new GPU implementation of the matched Separable Footprint pair is proposed. Since many of SAFRAN's industrial parts are piecewise-constant volumes, a Gauss-Markov-Potts prior model is introduced, from which a joint reconstruction and segmentation algorithm is derived. This algorithm is based on a Bayesian approach which enables to explain the role of each parameter. The actual polychromacy of X-rays, which is responsible for scattering and beam-hardening, is taken into account by proposing an error-splitting forward model. Combined with Gauss-Markov-Potts prior on the volume, this new forward model is experimentally shown to bring more accuracy and robustness. At last, the estimation of the uncertainties on the reconstruction is investigated by variational Bayesian approach. In order to have a reasonable computation time, it is highlighted that the use of a matched pair of projector and backprojector is necessary. Note de contenu : 1- X-ray computed tomography : an inverse problem 2- Reconstruction methods in X-ray computed tomography 3- Projection and backprojection operators 4- Gauss-Markov-Potts prior model for joint reconstruction and segmentation 5- Error-splitting forward model and its application with Gauss-Markov-Potts prior 6- Towards the estimation of the uncertainties on the reconstruction by Variational Bayesian Approach 7- Conclusion and perspectives Numéro de notice : 25702 Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Sciences et Technologies de l’Information et de la Communication (STIC) : Traitement du signal et des images : Paris 11 : 2019 Organisme de stage : Safran En ligne : https://tel.archives-ouvertes.fr/tel-02110033 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94827

X-ray microdensitometry of wood: A review of existing principles and devices / Philippe Jacquin in Dendrochronologia, vol 42 (March 2017)  

Public [article]  inDendrochronologia > vol 42 (March 2017) . - pp 42 - 50 Titre : X-ray microdensitometry of wood: A review of existing principles and devices Type de document : Article/Communication Auteurs : Philippe Jacquin, Auteur ; Fleur Longuetaud, Auteur ; Jean-Michel Leban , Auteur ; Frédéric Mothe, Auteur Année de publication : 2017 Article en page(s) : pp 42 - 50 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes descripteurs IGN] dendrochronologie [Termes descripteurs IGN] densité du bois [Termes descripteurs IGN] rayon X [Termes descripteurs IGN] tomographie Résumé : (auteur) Wood microdensitometry is the analysis of radial variations of density at the annual or intra-annual growth ring level. Density is related to wood quality, biomass, carbon content, tree growth and climate. Wood microdensitometry is particularly used in dendrochronology and climatology studies. The present study focuses on X-ray based methods used in wood microdensitometry analyses and provides a review of the main available devices. An exhaustive review of 75 works published on this topic in 2014 and 2015 showed that film-based equipment is still commonly used. The three other most popular devices, SilviScan, Itrax and QTRS, are also based on X-ray radiography and deliver results with comparable accuracy, below 50 μm per pixel. X-ray tomography (CT) is still rarely used in wood densitometry. Medical CT scanners currently offer a lower accuracy (above 100 μm per pixel) that is insufficient in most cases for ring or intra-ring scales. Micro-CT scanners offer good performance at the cost of much longer acquisition and reconstruction times. Numéro de notice : A2017-893 Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.dendro.2017.01.004 date de publication en ligne : 27/01/2017 En ligne : https://doi.org/10.1016/j.dendro.2017.01.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91887 [article]

Within-stem maps of wood density and water content for characterization of species: a case study on three hardwood and two softwood species / Fleur Longuetaud in Annals of Forest Science [en ligne], vol 73 n° 3 (September 2016)  

Public [article]  inAnnals of Forest Science [en ligne] > vol 73 n° 3 (September 2016) . - pp 601 - 614 Titre : Within-stem maps of wood density and water content for characterization of species: a case study on three hardwood and two softwood species Type de document : Article/Communication Auteurs : Fleur Longuetaud, Auteur ; Frédéric Mothe, Auteur ; Meriem Fournier, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 601 - 614 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes descripteurs IGN] Abies alba [Termes descripteurs IGN] acer pseudoplatanus [Termes descripteurs IGN] analyse discriminante [Termes descripteurs IGN] caractérisation [Termes descripteurs IGN] espèce végétale [Termes descripteurs IGN] Fagus sylvatica [Termes descripteurs IGN] pseudotsuga menziesii [Termes descripteurs IGN] quercus (genre) [Termes descripteurs IGN] teneur en eau de la végétation [Termes descripteurs IGN] tomographie [Termes descripteurs IGN] tronc [Termes IFN] densité du bois Résumé : (auteur) Key message : Variability and interrelations between wood density, water content, and related properties were analyzed by CT scanning of five species. Relative water content of lumens is proposed as the best complement to basic specific gravity for discrimination of species with respect to their functioning. Context : X-ray computed tomography (CT) is an efficient tool for analysis of wood properties related to density and water content all along a tree stem. Basic specific gravity, an inherent property of the wood material, is well known and widely used in wood sciences. Aims : The first aim of this study was to describe a method for mapping a set of wood properties within a tree stem. The second objective was to analyze the relations among these properties and to identify the one that offers the best information in addition to basic specific gravity for discrimination of species. Methods : Wood discs were collected at various heights along a tree stem. We used a method consisting of comparing the CT images of the discs in the green state and after oven drying. Finally, 10 variables were computed for 115 trees of five temperate species: green, oven-dry, and basic specific gravities; moisture content; relative water content; relative water content of lumens; and fractions of air, water, free water, and cell walls. Results : Maps of wood properties summarizing the radial and vertical variations were obtained, allowing us to highlight species-specific patterns. The five species were discriminated best when plotted in the plane defined by basic specific gravity and relative water content of lumens. Conclusion : The proposed method is original and simple enough to process large samples. Because it correlated less with basic specific gravity than with moisture content, relative water content of lumens was selected for species characterization. This is the first study of such wood properties at this fine scale within a tree stem, simultaneously and for a substantial number of trees of five species including both hardwoods and softwoods. Numéro de notice : A2016-710 Thématique : FORET Nature : Article En ligne : http://dx.doi.org/10.1007/s13595-016-0555-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82088 [article]

A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance / Jian Kong in Journal of geodesy, vol 90 n° 8 (August 2016)  

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Variations in the natural density of European oak wood affect thermal degradation during thermal modification / Joël Hamada in Annals of Forest Science [en ligne], vol 73 n° 2 (June 2016)  

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Combining spaceborne SAR images with 3D point clouds for infrastructure monitoring applications / Andrei Anghel in ISPRS Journal of photogrammetry and remote sensing, vol 111 (January 2016)  

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Voxel-optimized regional water vapor tomography and comparison with radiosonde and numerical weather model / Biyan Chen in Journal of geodesy, vol 88 n° 7 (July 2014)  

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Signal Processing / Charles L. Byrne (2014)  

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Assessment of an ancient bridge combining geophysical and advanced photogrammetric methods: Application to the Pont De Coq / Cyrille Fauchard in Journal of applied geophysics, vol 98 (November 2013)  

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Ground-based array for tomographic imaging of the tropical forest in P-band / Ho Tong Minh Dinh in IEEE Transactions on geoscience and remote sensing, vol 51 n° 8 (August 2013)  

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Phenomenology of ground scattering in a tropical forest through polarimetric synthetic aperture radar tomography / Mauro Mariotti d'Alessandro in IEEE Transactions on geoscience and remote sensing, vol 51 n° 8 (August 2013)  

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Three-dimensional reconstruction of man-made objects using polarimetric tomographic / Shi-Qi Xing in IEEE Transactions on geoscience and remote sensing, vol 51 n° 6 Tome 2 (June 2013)  

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Quantification de l'accélération des plaques tectoniques / Michelle Aubrun (2013)

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