Détail de l'auteur
Auteur Christian Thom
Commentaire :
Senior researcher since 1990 in LOEMI becoming LaSTIG, ACTE team
Autorités liées :
idHAL :
christian-thom
idRef :
autre URL :
ORCID :
Scopus :
G. Scholar :
DBLP URL :
|
Documents disponibles écrits par cet auteur (69)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Surface reconstruction in urban areas from multiple views of aerial digital frame cameras / Nicolas Paparoditis (2000)
Titre : Surface reconstruction in urban areas from multiple views of aerial digital frame cameras Type de document : Article/Communication Auteurs : Nicolas Paparoditis , Auteur ; Christian Thom , Auteur ; Hassan Jibrini , Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2000 Collection : International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, ISSN 1682-1750 num. 33-B3 Conférence : ISPRS 2000, 19th ISPRS Congress Technical Commission 3, Systems for Data Processing, Analysis and Representation 16/07/2000 23/07/2000 Amsterdam Pays-Bas OA Proceedings archives Importance : pp 43 - 50 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] appariement d'images
[Termes IGN] corrélation d'images
[Termes IGN] couple stéréoscopique
[Termes IGN] image aérienne
[Termes IGN] reconstruction d'objet
[Termes IGN] zone urbaineRésumé : (auteur) This paper describes an original approach and strategy for the automatic surface reconstruction of urban areas from digital aerial multiple views (across track as well as along track). The general reconstruction approach is based on a concept of multi-image matching guided from object space which provides the DSM and the corresponding orthoimage at the same time. The general idea is to match all the images at the same time with a multi-image correlation function instead of merging all elementary DSM computed on all stereopairs. This multi-image correlation function has very interesting properties, we can use very small templates (windows) in the image matching process, the correlation scores give a real reliability indicator of the matches and the false matches can be filtered with a deterministic threshold. All discarded areas are filled with a hierarchical matching strategy aiming at building the surface step by step. Numéro de notice : C2000-014 Affiliation des auteurs : MATIS+Ext (1993-2011) Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.isprs.org/proceedings/Xxxiii/congress/part3/43_XXXIII-part3s.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102891 Multilateration with the wide-angle laser ranging system: ranging performance and first ground-based validation experiment / Olivier Bock in IEEE Transactions on geoscience and remote sensing, vol 37 n° 2 Tome 2 (march 1999)
[article]
Titre : Multilateration with the wide-angle laser ranging system: ranging performance and first ground-based validation experiment Type de document : Article/Communication Auteurs : Olivier Bock , Auteur ; Christian Thom , Auteur ; Michel Kasser , Auteur ; Jacques Pelon, Auteur Année de publication : 1999 Article en page(s) : pp 739 - 747 Note générale : bibliographie Langues : Anglais (eng) Résumé : (auteur) A wide-angle laser ranging system has been developed for high-precision multilateration. A laser transmits short pulses in a widely diverging beam toward a network of cube-corner retroreflectors (CCRs). Returned echoes are detected, amplified, digitized, and timed. Impact of instrumental error sources, atmospheric refraction, and scintillation are discussed. The precision of the correlation method for the estimation of times of arrival and a least-squares adjustment method for the estimation of relative CCR coordinates is studied. Data from several ground-based experiments are analyzed. The positioning precision achieved is of 1-2.3 mm in relative radial coordinates and 1.8-3.8 cm in relative transverse coordinates. Results are consistent with a covariance analysis, demonstrating that, as follows: 1) systematic instrumental errors are well corrected; 2) outliers arising from coincident echoes are properly detected; 3) models for forward and inverse problems and estimation techniques are correct. A numerical simulation program based on these models and techniques can be used for optimizing instrumental aspects, providing extensive simulations in various conditions and processing data from future airborne experiments to which the system is devoted. Numéro de notice : A1999-023 Affiliation des auteurs : LOEMI+Ext (1985-2011) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/36.752190 Date de publication en ligne : 01/03/1999 En ligne : https://doi.org/10.1109/36.752190 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102811
in IEEE Transactions on geoscience and remote sensing > vol 37 n° 2 Tome 2 (march 1999) . - pp 739 - 747[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-99021B RAB Revue Centre de documentation En réserve L003 Disponible First aircraft experiment with the WA-ALRS / Olivier Bock (1999)
contenu dans Proceedings, 11th international workshop on laser ranging, Deggendorf, September 20 - 25, 1998, 2. Volume 2 / W. Schlüter (1999)
Titre : First aircraft experiment with the WA-ALRS Type de document : Article/Communication Auteurs : Olivier Bock , Auteur ; Michel Kasser , Auteur ; Christian Thom , Auteur Editeur : Francfort sur le Main : Bundesamt für Kartographie und Geodäsie Année de publication : 1999 Conférence : IWLR 1998, 11th international workshop on laser ranging 20/09/1998 25/09/1998 Deggendorf Allemagne OA Proceedings Importance : pp 761 - 767 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] précision centimétrique
[Termes IGN] précision millimétrique
[Termes IGN] télémètre laser aéroporté
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) An experiment has been conducted with the Wide Angle Airborne Laser Ranging System (WA-ALRS) in May 1998 over the ancient air base of Crucey, France. A flat area of~1.2xl.2 km around the airstrips has been specially equipped with a network of 8X8 CCRs. The ranging system was operated from the Avion de Recherche Atmosphérique et de Télédétection (ARAT), the French research aircraft for remote sensing of the CNES. Due to the small horizontal separation between the CCRs (about 150 m) it was expected that the return echoes were strongly overlapped. For this reason a revised version of the photodetector / amplifier stage has been used, with a shortened response time. Additionally, a relatively low flight path has been retained. Data have been collected during two 4-hour flights, of which 6,000 actual laser shots came out. The single-shot ranging accuracy was of 1-5 cm which should achieve a final positioning precision of 2-3 mm in the vertical. Data are currently being processed and seem to be able to confirm this prediction. Numéro de notice : C1998-029 Affiliation des auteurs : LOEMI (1985-2011) Thématique : POSITIONNEMENT Nature : Poster nature-HAL : Poster-avec-CL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65753
Titre : The IGN digital camera system in progress Type de document : Article/Communication Auteurs : Christian Thom , Auteur ; Jean-Philippe Souchon , Auteur Editeur : Karlsruhe, Heidelberg, ... : Wichmann Année de publication : 1999 Conférence : PhoWo 1999, 47th Photogrammetric Week 20/09/1999 24/09/1999 Stuttgart Allemagne OA proceedings Importance : pp 89 - 94 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] BD Topo
[Termes IGN] caméra numérique
[Termes IGN] instrumentation IGN
[Termes IGN] photographie en couleur
[Termes IGN] photographie panchromatique
[Termes IGN] Rennes
[Termes IGN] SaumurRésumé : (Auteur) The latest progress of IGN's project on digital cameras, that has begun in 1991, are described. The features of the present prototypes are presented. The results of the first attempt to use digital images in IGN production lines are given, - in color with an orthophoto on the city of Rennes, and - in panchromatic with a survey over the city of Saumur for the production of IGN's BD TOPO. The trends of the project are briefly assessed. Numéro de notice : C1999-025 Affiliation des auteurs : LOEMI (1985-2011) Thématique : IMAGERIE Nature : Communication DOI : sans En ligne : https://phowo.ifp.uni-stuttgart.de/publications/phowo99/thom.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65791 Study of a wide-angle laser ranging system for relative positioning of ground-based benchmarks with millimeter accuracy / Olivier Bock in Journal of geodesy, vol 72 n° 7-8 (July - August 1998)
[article]
Titre : Study of a wide-angle laser ranging system for relative positioning of ground-based benchmarks with millimeter accuracy Type de document : Article/Communication Auteurs : Olivier Bock , Auteur ; Michel Kasser , Auteur ; Christian Thom , Auteur ; Jacques Pelon, Auteur Année de publication : 1998 Article en page(s) : pp 442 - 459 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] benchmark spatial
[Termes IGN] DORIS
[Termes IGN] erreur systématique
[Termes IGN] Global Positioning System
[Termes IGN] positionnement différentiel
[Termes IGN] précision millimétrique
[Termes IGN] repère de nivellement
[Termes IGN] télémétrie laserRésumé : (Auteur) A wide-angle airborne laser ranging system (WA-ALRS) is developed at the Institut Géographique National (IGN), France, with the aim of providing a new geodesy technique devoted to large (100km) networks with a high density (1 km-2) of benchmarks. The main objective is to achieve a 1-mm accuracy in relative vertical coordinates from aircraft measurements lasting a few hours. This paper reviews the methodology and analyzes the first experimental data achieved from a specific ground-based experiment. The accuracy in relative coordinate estimates is studied with the help of numerical simulations. It is shown that strong accuracy limitations arise with a small laser beam divergence combined with short range measurements when relatively few simultaneous range data are produced. The accuracy is of a few cm in transverse coordinates and a few mm in radial coordinates. The results from groundbased experimental data are fairly compatible with these predictions. The use of a model for systematic errors in the vehicle trajectory is shown to be necessary to achieve such a high accuracy. This work yields the first complete validation of modelization and methodology of this technique. An accuracy better than 1 mm and a few mm in vertical and horizontal coordinates, respectively, is predicted for aircraft experiments. Numéro de notice : A1998-202 Affiliation des auteurs : LOEMI+Ext (1985-2011) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s001900050184 En ligne : http://dx.doi.org/10.1007/s001900050184 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26166
in Journal of geodesy > vol 72 n° 7-8 (July - August 1998) . - pp 442 - 459[article]A wide-angle airborne laser ranging system for millimetre accuracy subsidence measurements / Olivier Bock in Journal of optics, vol 29 n° 3 (June 1998)PermalinkLe point sur les caméras numériques de l'IGN / Christian Thom in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 149 (Janvier 1998)PermalinkAn aerial digital frame camera for photogrammetry: radiometric comparison with scanned imagery / Christian Thom in Geomatica, vol 51 n° 2 (June 1997)PermalinkDéveloppement d'un système de télémétrie laser destiné à la mesure de mouvements verticaux du sol de l'ordre du millimètre / Olivier Bock in Revue internationale de géomatique, vol 6 n° 2-3 (juin – août 1996)PermalinkPremières images de la nouvelle camera aérienne numérique / I. Juvillier in Revue internationale de géomatique, vol 6 n° 2-3 (juin – août 1996)PermalinkCaméra numérique de grand format pour les prises de vues aériennes à l'Institut Géographique National / Isabelle Jurvillier in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 132 (Octobre 1993)PermalinkRéalisation d'une caméra aérienne numérique / Christian Thom (1992)PermalinkConception et réalisation d'un appareil de traitement d'images interférométriques en comptage de photons / Christian Thom (1986)Permalink