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Projective texturing uncertain geometry: silhouette-aware box-filtered blending using integral radial images / Mathieu Brédif (2016)  

Public Titre : Projective texturing uncertain geometry: silhouette-aware box-filtered blending using integral radial images Type de document : Article/Communication Auteurs : Mathieu Brédif , Auteur Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2016 Projets : iSpace&Time / Brédif, Mathieu Conférence : JFIG 2016, 29èmes Journées Française d’Informatique Graphique de l'AFIG, du GdR IG-RV du CNRS et du Chapitre Français d’EG 30/11/2016 02/12/2016 Grenoble France Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] filtre passe-bas [Termes IGN] géométrie de l'image [Termes IGN] incertitude géométrique [Termes IGN] modèle géométrique de prise de vue [Termes IGN] texturage Résumé : (auteur) Projective texturing is a commonly used image based rendering technique that enables the synthesis of novel views from the blended reprojection of nearby views on a coarse geometry proxy approximating the scene. When scene geometry is inexact, aliasing artefacts occur. This introduces disturbing artefacts in applications such as street-level immersive navigation in mobile mapping imagery, since a pixel-accurate modelling of the scene geometry and all its details is most of the time out of question. The filtered blending approach applies the necessary 1D low-pass filtering on the projective texture to trade out the aliasing artefacts at the cost of some radial blurring. This paper proposes extensions of the filtered blending approach. Firstly, we introduce Integral Radial Images that enable constant time radial box filtering and show how they can be used to apply box-filtered blending in constant time independently of the amount of depth uncertainty. Secondly, we show a very efficient application of filtered blending where the scene geometry is only given by a loose depth interval prior rather than an actual geometry proxy. Thirdly, we propose a silhouette-aware extension of the box-filtered blending that not only account for uncertain depth along the viewing ray but also for uncertain silhouettes that have to be blurred as well Numéro de notice : C2016-063 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésNat DOI : sans En ligne : https://hal.science/hal-02551490 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96340

Investigating the mobile phone data to estimate the origin destination flow and analysis, a case study: Paris region / Anahid Nabavi-Larijani in Transportation Research Procedia, vol 6 (2015)    

Public [article]  inTransportation Research Procedia > vol 6 (2015) . - pp 64 - 78 Titre : Investigating the mobile phone data to estimate the origin destination flow and analysis, a case study: Paris region Type de document : Article/Communication Auteurs : Anahid Nabavi-Larijani, Auteur ; Ana-Maria Olteanu-Raimond , Auteur ; Julien Perret , Auteur ; Mathieu Brédif , Auteur Année de publication : 2015 Projets : iSpace&Time / Brédif, Mathieu Conférence : ISTS 2014, 4th International Symposium of Transport Simulation 01/06/2014 04/06/2014 Ajaccio France Proceedings Elsevier Article en page(s) : pp 64 - 78 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] Ile-de-France [Termes IGN] origine - destination [Termes IGN] téléphone intelligent [Termes IGN] téléphonie mobile Résumé : (auteur) This paper is an output of a French national project called iSpace&Time aiming to provide a 4 dimensional platform of an urban dynamics. In order to express the urban traffic, we took an advantage of the mobile phone data to investigate the behavior of the origin destination flow within the Paris and its suburb aiming to explore the different mode of the transportation. Indeed the spatiotemporal heterogeneities of mobile phone data make the task of mode of transportation separation very challenging, sometimes even impossible. Thus, by exploring the OD matrix in order to revealing any probable continues trends or any dominant trace of the flow stating a specific mode of transportation, the commuter trains happened to be somehow detectable. Then an individual-based step-by-step approach is proposed to estimate mode of transportation from mobile phone data. Analyzing the individual trajectory, the decision is given to a segment level with respect to different measures. An early promising outcome consists of detection of the segments in which people would take the metro. Numéro de notice : A2015-997 Affiliation des auteurs : LASTIG COGIT+Ext (2012-2019) Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.trpro.2015.03.006 Date de publication en ligne : 26/04/2015 En ligne : https://doi.org/10.1016/j.trpro.2015.03.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79966 [article]

Documents numériques

en open access Investigating the mobile phone data Adobe Acrobat PDF

Projective texturing uncertain geometry: silhouette-aware box-filtered blending using integral radial images / Mathieu Brédif in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol II-3 (September 2014)    

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol II-3 (September 2014) . - pp 17 - 23 Titre : Projective texturing uncertain geometry: silhouette-aware box-filtered blending using integral radial images Type de document : Article/Communication Auteurs : Mathieu Brédif , Auteur Année de publication : 2014 Projets : iSpace&Time / Brédif, Mathieu Conférence : PCV 2014, ISPRS Technical Commission 3 Symposium Photogrammetric Computer vision 05/09/2014 07/09/2014 Zurich Suisse OA ISPRS Annals Article en page(s) : pp 17 - 23 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] incertitude géométrique [Termes IGN] navigation virtuelle [Termes IGN] rendu réaliste [Termes IGN] texturage Résumé : (auteur) Projective texturing is a commonly used image based rendering technique that enables the synthesis of novel views from the blended reprojection of nearby views on a coarse geometry proxy approximating the scene. When scene geometry is inexact, aliasing artefacts occur. This introduces disturbing artefacts in applications such as street-level immersive navigation in mobile mapping imagery, since a pixel-accurate modelling of the scene geometry and all its details is most of the time out of question. The filtered blending approach applies the necessary 1D low-pass filtering on the projective texture to trade out the aliasing artefacts at the cost of some radial blurring. This paper proposes extensions of the filtered blending approach. Firstly, we introduce Integral Radial Images that enable constant time radial box filtering and show how they can be used to apply box-filtered blending in constant time independently of the amount of depth uncertainty. Secondly, we show a very efficient application of filtered blending where the scene geometry is only given by a loose depth interval prior rather than an actual geometry proxy. Thirdly, we propose a silhouette-aware extension of the box-filtered blending that not only account for uncertain depth along the viewing ray but also for uncertain silhouettes that have to be blurred as well. Numéro de notice : A2014-775 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-II-3-17-2014 Date de publication en ligne : 15/09/2014 En ligne : http://dx.doi.org/10.5194/isprsannals-II-3-17-2014 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78723 [article]

Documents numériques

en open access Projective texturing uncertain geometry Adobe Acrobat PDF

Image-based rendering of LOD1 3D city models for traffic-augmented immersive street-view navigation / Mathieu Brédif in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol II-3 W3 (November 2013)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol II-3 W3 (November 2013) . - pp 7 - 11 Titre : Image-based rendering of LOD1 3D city models for traffic-augmented immersive street-view navigation Type de document : Article/Communication Auteurs : Mathieu Brédif , Auteur Année de publication : 2013 Projets : iSpace&Time / Brédif, Mathieu Conférence : CMRT 2013, City Models, Roads and Traffic 12/11/2013 13/11/2013 Antalya Turquie OA ISPRS Annals Article en page(s) : pp 7 - 11 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] modèle 3D de l'espace urbain [Termes IGN] navigation virtuelle [Termes IGN] niveau de détail [Termes IGN] rendu réaliste [Termes IGN] simulation 3D [Termes IGN] système de numérisation mobile [Termes IGN] texturage [Termes IGN] trafic routier [Termes IGN] visualisation 3D Résumé : (auteur) It may be argued that urban areas may now be modeled with sufficient details for realistic fly-through over the cities at a reasonable price point. Modeling cities at the street level for immersive street-view navigation is however still a very expensive (or even impossible) operation if one tries to match the level of detail acquired by street-view mobile mapping imagery. This paper proposes to leverage the richness of these street-view images with the common availability of nation-wide LOD1 3D city models, using an image-based rendering technique : projective multi-texturing. Such a coarse 3D city model may be used as a lightweight scene proxy of approximate coarse geometry. The images neighboring the interpolated viewpoint are projected onto this scene proxy using their estimated poses and calibrations and blended together according to their relative distance. This enables an immersive navigation within the image dataset that is perfectly equal to – and thus as rich as – original images when viewed from their viewpoint location, and which degrades gracefully in between viewpoint locations. Beyond proving the applicability of this preprocessing-free computer graphics technique to mobile mapping images and LOD1 3D city models, our contributions are three-fold. Firstly, image distortion is corrected online in the GPU, preventing an extra image resampling step. Secondly, externally-computed binary masks may be used to discard pixels corresponding to moving objects. Thirdly, we propose a shadowmap-inspired technique that prevents, at marginal cost, the projective texturing of surfaces beyond the first, as seen from the projected image viewpoint location. Finally, an augmented visualization application is introduced to showcase the proposed immersive navigation: images are unpopulated from vehicles using externally-computed binary masks and repopulated using a 3D visualization of a 2D traffic simulation. Numéro de notice : A2013-793 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-II-3-W3-7-2013 En ligne : http://dx.doi.org/10.5194/isprsannals-II-3-W3-7-2013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80399 [article]

2D arrangement-based hierarchical spatial partitioning: an application to pedestrian network generation / Murat Yirci (2013)  

Public contenu dans Proceedings of the Sixth ACM SIGSPATIAL International Workshop on Computational Transportation Science / Craig A. Knoblock (2013)   Titre : 2D arrangement-based hierarchical spatial partitioning: an application to pedestrian network generation Type de document : Article/Communication Auteurs : Murat Yirci, Auteur ; Mathieu Brédif , Auteur ; Julien Perret , Auteur ; Nicolas Paparoditis , Auteur Editeur : New York [Etats-Unis] : Association for computing machinery ACM Année de publication : 2013 Projets : iSpace&Time / Brédif, Mathieu Conférence : IWCTS 2013, 6th ACM SIGSPATIAL International Workshop on Computational Transportation Science 05/11/2013 08/11/2013 Orlando Floride - Etats-Unis Proceedings ACM Projets : Terra Mobilita / Brédif, Mathieu Importance : pp 31 - 36 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] algorithme génétique [Termes IGN] connexité (graphes) [Termes IGN] données vectorielles [Termes IGN] information sémantique [Termes IGN] modèle conceptuel de données localisées [Termes IGN] partition des données [Termes IGN] partitionnement [Termes IGN] squelettisation [Termes IGN] théorie des graphes Résumé : (auteur) This paper addresses the creation and maintenance of partitions of city surfaces for mapping and transportation applications. It proposes a hierarchical spatial surface partitioning, encoding the spatial partition with a 2D arrangement and structuring a generic hierarchy of semantic objects with a directed acyclic graph (DAG), in which the leaves point to the partition elements (polygonal regions, line strings, points). Semantic objects such as buildings, sidewalks and roads are described by grouping other objects and partition elements with their semantic relationships. In the proposed generic data model, geometry and spatial relationships of the semantic objects are respectively described by the geometry and topology of the planar partition. The proposed geometric data structure for creating and maintaining this partition is a 2D arrangement. In addition, the hierarchical object model encodes the thematic and semantic relationships between the objects. Besides the data model, methods and algorithms are discussed for leveraging existing vector datasets to create and maintain such partitions. These partitions are then fit to further processing and analysis using computational geometry and graph theory algorithms. For this purpose, three application-wise generic algorithms were integrated into our system called Streetmaker: two skeleton operators for centerline generation (straight skeleton and medial axis) and connectivity graphs for itinerary calculations. Moreover, specific algorithms can be integrated into Streetmaker for specific applications. We demonstrated an example usage of this framework for generating static obstacle avoiding pedestrian network graphs. The representation of the network graph and the process used to generate it, can be considered as the second contribution of our work besides the proposed data model. Numéro de notice : C2013-004 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : GEOMATIQUE Nature : Communication DOI : 10.1145/2533828.2533843 En ligne : http://dx.doi.org/10.1145/2533828.2533843 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80064