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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, vol 73 n° 3 (September 2016)
[article]
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 IGN] Abies alba
[Termes IGN] Acer pseudoplatanus
[Termes IGN] analyse discriminante
[Termes IGN] caractérisation
[Termes IGN] densité du bois
[Termes IGN] espèce végétale
[Termes IGN] Fagus sylvatica
[Termes IGN] Pseudotsuga menziesii
[Termes IGN] Quercus (genre)
[Termes IGN] teneur en eau de la végétation
[Termes IGN] tomographie
[Termes IGN] troncRésumé : (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 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-016-0555-4 Date de publication en ligne : 20/05/2016 En ligne : https://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
in Annals of Forest Science > vol 73 n° 3 (September 2016) . - pp 601 - 614[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)
[article]
Titre : A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance Type de document : Article/Communication Auteurs : Jian Kong, Auteur ; Yi Bin Yao, Auteur ; Lei Liu, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 741 – 755 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] altération
[Termes IGN] correction troposphérique
[Termes IGN] International Reference Ionosphere
[Termes IGN] Japon
[Termes IGN] séisme
[Termes IGN] teneur totale en électrons
[Termes IGN] tomographie
[Termes IGN] troposphèreRésumé : (auteur) A new algorithm for ionosphere tomography using the mapping function is proposed in this paper. First, the new solution splits the integration process into four layers along the observation ray, and then, the single-layer model (SLM) is applied to each integration part using a mapping function. Next, the model parameters are estimated layer by layer with the Kalman filtering method by introducing the scale factor (SF) γ to solve the ill-posed problem. Finally, the inversed images of different layers are combined into the final CIT image. We utilized simulated data from 23 IGS GPS stations around Europe to verify the estimation accuracy of the new algorithm; the results show that the new CIT model has better accuracy than the SLM in dense data areas and the CIT residuals are more closely grouped. The stability of the new algorithm is discussed by analyzing model accuracy under different error levels (the max errors are 5TECU, 10TECU, 15TECU, respectively). In addition, the key preset parameter, SFγ, which is given by the International Reference Ionosphere model (IRI2012). The experiment is designed to test the sensitivity of the new algorithm to SF variations. The results show that the IRI2012 is capable of providing initial SF values. Also in this paper, the seismic-ionosphere disturbance (SID) of the 2011 Japan earthquake is studied using the new CIT algorithm. Combined with the TEC time sequence of Sat.15, we find that the SID occurrence time and reaction area are highly related to the main shock time and epicenter. According to CIT images, there is a clear vertical electron density upward movement (from the 150-km layer to the 450-km layer) during this SID event; however, the peak value areas in the different layers were different, which means that the horizontal movement velocity is not consistent among the layers. The potential physical triggering mechanism is also discussed in this paper. Compared with the SLM, the RMS of the new CIT model is improved by 16.78%, while the CIT model could provide the three-dimensional variation in the ionosphere. Numéro de notice : A2016-504 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0906-9 En ligne : http://dx.doi.org/10.1007/s00190-016-0906-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81528
in Journal of geodesy > vol 90 n° 8 (August 2016) . - pp 741 – 755[article]Variations in the natural density of European oak wood affect thermal degradation during thermal modification / Joël Hamada in Annals of Forest Science, vol 73 n° 2 (June 2016)
[article]
Titre : Variations in the natural density of European oak wood affect thermal degradation during thermal modification Type de document : Article/Communication Auteurs : Joël Hamada, Auteur ; Anélie Pétrissans, Auteur ; Frédéric Mothe, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 277 - 286 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] bois
[Termes IGN] densité du bois
[Termes IGN] effet thermique
[Termes IGN] industrie forestière
[Termes IGN] Quercus (genre)
[Termes IGN] sylviculture
[Termes IGN] tomographie
[Vedettes matières IGN] ForesterieRésumé : (auteur) Key message : Thermogravimetric analysis, performed on small samples of earlywood (EW) or latewood (LW), indicated that earlywood is more susceptible to thermal degradation than latewood. These results suggest a direct relationship between wood density (which depends on the EW/LW ratio and indirectly on silviculture) and the response of wood during thermo-modification processes.
Context: One of the main difficulties in developing thermo-modified wood products at an industrial scale lies in the difficulty of obtaining consistent products with a stable quality (durability, dimensional stability, color). This may be due either to the thermal treatment process itself or to inter- or intra-specific heterogeneity of wood properties.
Aims: We investigated the effect of the natural variability of oak wood, particularly in density, on the degree of thermo-degradation during thermal treatments.
Methods: X-ray computed tomography was used to assess the effect of initial wood density of oak boards on their thermo-degradation. Intra-ring wood density was estimated using thermogravimetric analysis and micro-densitometry.
Results: X-ray CT did not allow establishment of a clear correlation between initial wood density and mass loss due to thermo-degradation, while thermogravimetric analysis, performed separately on earlywood and latewood samples, revealed a larger susceptibility to thermal degradation of the less dense earlywood samples compared to more dense latewood samples
Conclusion: Initial wood density, which is directly controlled by the earlywood/latewood ratio modulated by silvicultural practices, directly influences thermo-degradation during thermal treatment. Initial wood density therefore appears to be a potential parameter influencing industrial thermal treatment processes.Numéro de notice : A2016-349 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-015-0499-0 Date de publication en ligne : 16/07/2015 En ligne : https://doi.org/10.1007/s13595-015-0499-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81060
in Annals of Forest Science > vol 73 n° 2 (June 2016) . - pp 277 - 286[article]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)
[article]
Titre : Combining spaceborne SAR images with 3D point clouds for infrastructure monitoring applications Type de document : Article/Communication Auteurs : Andrei Anghel, Auteur ; Gabriel Vasile, Auteur ; Rémy Boudon, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 45 – 61 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image mixte
[Termes IGN] analyse combinatoire (maths)
[Termes IGN] appariement d'images
[Termes IGN] France métropolitaine
[Termes IGN] image radar moirée
[Termes IGN] semis de points
[Termes IGN] test de performance
[Termes IGN] tomographieRésumé : (auteur) The measurement and monitoring of critical infrastructure elements by remote sensing has become necessary for economical and security reasons. Information provided by remote sensing for infrastructure monitoring is extracted with specific signal processing chains that have to be adapted to the geometric particularities of the structure. In this paper we present in detail the first monitoring results obtained by combining spaceborne synthetic aperture radar (SAR) data with externally measured point clouds describing an infrastructure element. The processing core is essentially based on refocusing each available SAR image on the provided point cloud and identifying the scatterers that can be monitored by means of four dimensional tomography. The key points and limitations which appear in the measurement and data processing are illustrated on two test sites in France: the Puylaurent water-dam and the Chastel landslide. The SAR products used are high-resolution sliding spotlight SAR images acquired in the TerraSAR-X and TanDEM-X missions, whereas the point clouds of the structures were generated using GPS localization, topographic measurements and laser scans. The estimated deformations of the scatterers using the SAR images were in good agreement with available in-situ data provided through regular topographic surveys and embedded measuring systems. Numéro de notice : A2016-040 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.11.008 Date de publication en ligne : 17/12/2015 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.11.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79520
in ISPRS Journal of photogrammetry and remote sensing > vol 111 (January 2016) . - pp 45 – 61[article]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)
[article]
Titre : Voxel-optimized regional water vapor tomography and comparison with radiosonde and numerical weather model Type de document : Article/Communication Auteurs : Biyan Chen, Auteur ; Z. Liu, Auteur Année de publication : 2014 Article en page(s) : pp 691 - 703 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] positionnement par GNSS
[Termes IGN] tomographie
[Termes IGN] vapeur d'eau
[Termes IGN] voxelRésumé : (Auteur)Water vapor tomography has been developed as a powerful tool to model spatial and temporal distribution of atmospheric water vapor. Global navigation satellite systems (GNSS) water vapor tomography refers to the 3D structural construction of tropospheric water vapor using a large number of GNSS signals that penetrate the tomographic modeling area from different positions. The modeling area is usually discretized into a number of voxels. A major issue involved is that some voxels are not crossed by any GNSS signal rays, resulting in an undetermined solution to the tomographic system. To alleviate this problem, the number of voxels crossed by GNSS signal rays should be as large as possible. An important way to achieve this is to optimize the geographic distribution of tomographic voxels. We propose an approach to optimize voxel distribution in both vertical and horizontal domains. In the vertical domain, water vapor profiles derived from radiosonde data are exploited to identify the maximum height of tomography and the optimal vertical resolution. In the horizontal domain, the optimal horizontal distribution of voxels is obtained by searching the maximum number of ray-crossing voxels in both latitude and longitude directions. The water vapor tomography optimization procedures are implemented using GPS water vapor data from the Hong Kong Satellite Positioning Reference Station Network. The tomographic water vapor fields solved from the optimized tomographic voxels are evaluated using radiosonde data and a numerical weather prediction non-hydrostatic model (NHM) obtained for the Hong Kong station. The comparisons of tomographic integrated water vapor (IWV) with the radiosonde and NHM IWV show that RMS errors of their differences are 1.41 and 3.09 mm, respectively. Moreover, the tomographic water vapor density results are compared with those of radiosonde and NHM. The RMS error of the density differences between tomography and radiosonde data is 1.05 g/m3 . For the comparison between tomography and NHM, an overall RMS error of 1.43g/m3 is achieved. Numéro de notice : A2014-415 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0713-0 Date de publication en ligne : 08/04/2014 En ligne : https://doi.org/10.1007/s00190-014-0713-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=73956
in Journal of geodesy > vol 88 n° 7 (July 2014) . - pp 691 - 703[article]Réservation
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