Descripteur
Documents disponibles dans cette catégorie (12)
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesEtendre la recherche sur niveau(x) vers le bas
Real-time web map construction based on multiple cameras and GIS / Xingguo Zhang in ISPRS International journal of geo-information, vol 10 n° 12 (December 2021)
Titre : Real-time web map construction based on multiple cameras and GIS Type de document : Article/Communication Auteurs : Xingguo Zhang, Auteur ; Xinyu Shi, Auteur ; Xiaoyue Luo, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 803 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web
[Termes IGN] caméra vidéo numérique
[Termes IGN] connecteur logiciel
[Termes IGN] détection d'objet
[Termes IGN] homologie
[Termes IGN] système d'information géographique
[Termes IGN] temps réel
[Termes IGN] visualisation cartographique
[Termes IGN] web mapping
[Termes IGN] WebSIGRésumé : (auteur) Previous VideoGIS integration methods mostly used geographic homography mapping. However, the related processing techniques were mainly for independent cameras and the software architecture was C/S, resulting in large deviations in geographic video mapping for small scenes, a lack of multi-camera video fusion, and difficulty in accessing real-time information with WebGIS. Therefore, we propose real-time web map construction based on the object height and camera posture (RTWM-HP for short). We first consider the constraint of having a similar height for each object by constructing an auxiliary plane and establishing a high-precision homography matrix (HP-HM) between the plane and the map; thus, the accuracy of geographic video mapping can be improved. Then, we map the objects in the multi-camera video with overlapping areas to geographic space and perform the object selection with the multi-camera (OS-CDD) algorithm, which includes the confidence of the object, the distance, and the angle between the objects and the center of the cameras. Further, we use the WebSocket technology to design a hybrid C/S and B/S software framework that is suitable for WebGIS integration. Experiments were carried out based on multi-camera videos and high-precision geospatial data in an office and a parking lot. The case study’s results show the following: (1) The HP-HM method can achieve the high-precision geographic mapping of objects (such as human heads and cars) with multiple cameras; (2) the OS-CDD algorithm can optimize and adjust the positions of the objects in the overlapping area and achieve a better map visualization effect; (3) RTWM-HP can publish real-time maps of objects with multiple cameras, which can be browsed in real time through point layers and hot-spot layers through WebGIS. The methods can be applied to some fields, such as person or car supervision and the flow analysis of customers or traffic passengers. Numéro de notice : A2021-883 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi10120803 Date de publication en ligne : 28/11/2021 En ligne : https://doi.org/10.3390/ijgi10120803 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99186
in ISPRS International journal of geo-information > vol 10 n° 12 (December 2021) . - n° 803[article]Planimetric simplification and lexicographic optimal chains for 3D urban scene reconstruction / Julien Vuillamy (2021)
Titre : Planimetric simplification and lexicographic optimal chains for 3D urban scene reconstruction Type de document : Thèse/HDR Auteurs : Julien Vuillamy, Auteur ; Pierre Alliez, Directeur de thèse Editeur : Nice : Université Côte d'Azur Année de publication : 2021 Importance : 129 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse Présentée en vue de l’obtention du grade de docteur en Informatique d’Université Côte d’AzurLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] complexe simplicial
[Termes IGN] géométrie de Riemann
[Termes IGN] homologie
[Termes IGN] maillage
[Termes IGN] modèle 3D de l'espace urbain
[Termes IGN] optimisation (mathématiques)
[Termes IGN] programmation linéaire
[Termes IGN] reconstruction 3D du bâti
[Termes IGN] scène urbaine
[Termes IGN] semis de points
[Termes IGN] simplification de surface
[Termes IGN] triangulation de DelaunayIndex. décimale : THESE Thèses et HDR Résumé : (auteur) Creating mesh representations for urban scenes is a requirement for numerous modern applications of urban planning ranging from visualization, inspection, to simulation. Adding to the diversity of possible input data -- photography, laser-based acquisitions and existing geographical information system (GIS) data, the variety of urban scenes as well as the large-scale nature of the problem makes for a challenging line of research. Working towards an automatic approach to this problem suggests that a one-fits-all method is hardly realistic. Two independent approaches of reconstruction from point clouds have thus been investigated in this work, with radically different points of view intended to cover a large number of use cases. In the spirit of the GIS community, the first approach makes strong assumptions on the reconstructed scenes and creates a 2.5D piecewise-planar representation of buildings using an intermediate 2D cell decomposition. Constructing these decompositions from noisy or incomplete data often leads to overly complex representations, which lack the simplicity or regularity expected in this context of reconstruction. Loosely inspired by clustering problems such as mean-shift, the focus is put on simplifying such partitions by formulating an optimization process based on a tradeoff between attachment to the original partition and objectives striving to simplify and regularize the arrangement. This method involves working with point-line duality, defining local metrics for line movements and optimizing using Riemannian gradient descent. The second approach is intended to be used in contexts where the strong assumptions on the representation of the first approach do not hold. We strive here to be as general as possible and investigate the problem of point cloud meshing in the context of noisy or incomplete data. By considering a specific minimization, corresponding to lexicographic orderings on simplicial chains, polynomial-time algorithms finding lexicographic optimal chains, homologous to a given chain or bounded by a given chain, are derived from algorithms for the computation of simplicial persistent homology. For pseudomanifold complexes in codimension 1, leveraging duality and an augmented version of the disjoint-set data structure improves the complexity of these problem instances to quasi-linear time algorithms. By combining its uses with a sharp feature detector in the point cloud, we illustrate different use cases in the context of urban reconstruction. Note de contenu : 1- Introduction
2- State of the art and contributions
3- Parsimonious representations from 2D partitions
4- Dense representations from lexicographic optimal chains
5- Conclusion and perspectivesNuméro de notice : 28655 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Thèse française Note de thèse : Thèse de Doctorat : Informatique : Côte d'Azur : 2021 Organisme de stage : INRIA DOI : sans En ligne : https://hal.science/tel-03339931 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99797
Titre : Modelling and analysing 3D buildings with a primal/dual data structure Type de document : Article/Communication Auteurs : P. Boguslawski, Auteur ; Christopher Gold, Auteur ; Hugo Ledoux, Auteur Année de publication : 2011 Article en page(s) : pp 188 - 197 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] bati
[Termes IGN] CityGML
[Termes IGN] graphe
[Termes IGN] homologie
[Termes IGN] modèle topologique de données
[Termes IGN] modélisation 3D
[Termes IGN] structure de données localiséesRésumé : (Auteur) While CityGML permits us to represent 3D city models, its use for applications where spatial analysis and/or real-time modifications are required is limited since at this moment the possibility to store topological relationships between the elements is rather limited and often not exploited. We present in this paper a new topological data structure, the dual half-edge (DHE), which permits us to represent the topology of 3D buildings (including their interiors) and of the surrounding terrain. It is based on the idea of simultaneously storing a graph in 3D space and its dual graph, and to link the two. We propose Euler-type operators for incrementally constructing 3D models (for adding individual edges, faces and volumes to the model while updating the dual structure simultaneously), and we also propose navigation operators to move from a given point to all the connected planes or polyhedra for example. The DHE also permits us to store attributes to any element. We have implemented the DHE and have tested it with different CityGML models. Our technique allows us to handle important query types, for example finding the nearest exterior exit to a given room, as in disaster management planning. As the structure is locally modifiable the model may be adapted whenever a particular pathway is no longer available. The proposed DHE structure adds significant analytic value to the increasingly popular CityGML model. Numéro de notice : A2011-072 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.11.003 Date de publication en ligne : 28/12/2010 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.11.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30853
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 2 (March - April 2011) . - pp 188 - 197[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2011021 SL Revue Centre de documentation Revues en salle Disponible
Titre : Co-registration and inter-sensor comparison of MODIS and LANDSAT 7 ETM+ data aimed at NDVI calculation Type de document : Article/Communication Auteurs : P. Boccardo, Auteur ; Enrico Borgogno Mondino, Auteur ; et al., Auteur Année de publication : 2006 Conférence : ISPRS 2006, Commission 1 Symposium, From sensors to imagery 03/07/2006 06/07/2006 Champs-sur-Marne [Paris Marne-la-Vallée] France OA ISPRS Archives Article en page(s) : pp 74 - 79 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] erreur systématique
[Termes IGN] homologie
[Termes IGN] image Landsat-ETM+
[Termes IGN] image Terra-MODIS
[Termes IGN] limite de résolution géométrique
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] superposition d'imagesRésumé : (Auteur) To evaluate accuracy of low resolution vegetation mapping for hydrological purposes, a comparative study of NDVI images derived from MODIS and Landsat 7 ETM+ data has been done. Main goal is to understand how effective MODIS images can be for vegetation characterization on large areas, as compared to the Landsat 7 ETM+ ones. In this paper a methodology is proposed with the aim of measuring the difference between NDVI values derived from the two different data, considering synthetic parameters and investigating their dependency on the geometric resolution of the images. Great attention was paid to the problem of the geometric co-registration of the two types of data. This is a very sensitive parameter for the subsequent analysis. A mixed approach was adopted: images were firstly orthoprojected to eliminate sensor geometry and relief displacement effects; subsequently, a refining image-to-image co-registration procedure was carried out through a homographic transformation implemented in a self-developed routine. Two pairs of contemporary images (MODIS and Landsat 7) were used as benchmarks for our tests. Simplified procedures aimed at calibrating images and at removing atmospheric noise were performed. The resulting corrected images were used to calculate NDVI images. These ones (two pairs) were then compared through a statistical approach in order to investigate how a different geometric resolution can influence the NDVI values. The proposed approach is not a traditional image based (matrix comparison) but a new one. NDVI value correspondences were considered between the MODIS pixel and the group of Landsat pixels belonging to the polygon which represents the considered MODIS pixel in the Landsat image space. Statistics extracted on-the-fly from these Landsat pixels were used to investigate in depth the relationship between them and NDVI value of the corresponding MODIS pixel. NDVI differences were calculated between the single NDVI MODIS values and a synthetic parameter (mean value) of the homologous Landsat pixel group. A direct comparison between the NDVI values obtained from MODIS and Landsat 7 images has shown a systematic error that can be read as bias (MODIS NDVI over estimation). This led the authors to determine a suitable model in order to eliminate the bias, whose presence would have conditioned later comparisons. Original MODIS image was then corrected through the defined model. This has been designed to be suitable for any MODIS image acquired over the same area (parameterization was used). New NDVI differences were calculated using the corrected MODIS images and the previous Landsat 7 ones. In order to investigate the nature of the residual differences and to try to recognize the critical MODIS pixels, some considerations were made concerning the statistics of each corresponding group of Landsat pixels. A classification of the MODIS pixel was generated according to the behaviour of their differences with respect to the adopted statistics. Copyright SFPT Numéro de notice : A2006-624 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueNat DOI : sans En ligne : https://www.isprs.org/proceedings/XXXVI/part1/Papers/PS1-04.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28347
in Revue Française de Photogrammétrie et de Télédétection > n° 182 (Juin 2006) . - pp 74 - 79[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 018-06021 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : A combinatorial data model for representing topological relations among 3D geographical features in micro-spatial environments Type de document : Article/Communication Auteurs : J. Lee, Auteur ; Mei-Po Kwan, Auteur Année de publication : 2005 Article en page(s) : pp 1039 - 1056 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] analyse spatiale
[Termes IGN] approche hiérarchique
[Termes IGN] bati
[Termes IGN] homologie
[Termes IGN] modèle topologique de données
[Termes IGN] objet géographique 3D
[Termes IGN] relation topologique
[Termes IGN] requête spatiale
[Termes IGN] SIG 3D
[Termes IGN] théorie des graphes
[Termes IGN] visualisation 3DRésumé : (Auteur) This research is motivated by the need for 3D GIS data models that allow for 3D spatial query, analysis and visualization of the subunits and internal network structure of 'micro-spatial environments' (the 3D spatial structure within buildings). It explores a new way of representing the topological relationships among 3D geographical features such as buildings and their internal partitions or subunits. The 3D topological data model is called the combinatorial data model (CDM). It is a logical data model that simplifies and abstracts the complex topological relationships among 3D features through a hierarchical network structure called the node-relation structure (NRS). This logical network structure is abstracted by using the property of Poincaré duality. It is modelled and presented in the paper using graph-theoretic formalisms. The model was implemented with real data for evaluating its effectiveness for performing 3D spatial queries and visualization. Numéro de notice : A2005-498 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810500399043 En ligne : https://doi.org/10.1080/13658810500399043 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27634
in International journal of geographical information science IJGIS > vol 19 n° 10 (november 2005) . - pp 1039 - 1056[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-05091 RAB Revue Centre de documentation En réserve L003 Disponible 079-05092 RAB Revue Centre de documentation En réserve L003 Disponible PermalinkPermalinkExploitation des photographies aériennes à axe vertical (sans appareils de restitution) / Jean Carré (1963)
PermalinkPermalinkPermalinkPermalinkPermalink
