Détail de l'auteur
Auteur Pierre Alliez |
Documents disponibles écrits par cet auteur (5)



Planimetric simplification and lexicographic optimal chains for 3D urban scene reconstruction / Julien Vuillamy (2021)
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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 : Des images satellites aux cartes vectorielles Type de document : Thèse/HDR Auteurs : Onur Tasar, Auteur ; Pierre Alliez, Directeur de thèse Editeur : Nice : Université Côte d'Azur Année de publication : 2020 Importance : 151 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse présentée en vue de l'obtention du grade de docteur en Automatique, Traitement du Signal et des Images de l'Université Côte d'AzurLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] apprentissage profond
[Termes IGN] classification dirigée
[Termes IGN] classification par réseau neuronal convolutif
[Termes IGN] classification pixellaire
[Termes IGN] données d'entrainement (apprentissage automatique)
[Termes IGN] données massives
[Termes IGN] données matricielles
[Termes IGN] généralisation cartographique
[Termes IGN] géomètrie algorithmique
[Termes IGN] image aérienne
[Termes IGN] image satellite
[Termes IGN] maillage
[Termes IGN] représentation vectorielle
[Termes IGN] segmentation sémantique
[Termes IGN] vectorisationIndex. décimale : THESE Thèses et HDR Résumé : (auteur) With the help of significant technological developments over the years, it has been possible to collect massive amounts of remote sensing data. For example, the constellations of various satellites are able to capture large amounts of remote sensing images with high spatial resolution as well as rich spectral information over the globe. The availability of such huge volume of data has opened the door to numerous applications and raised many challenges. Among these challenges, automatically generating accurate maps has become one of the most interesting and long-standing problems, since it is a crucial process for a wide range of applications in domains such as urban monitoring and management, precise agriculture, autonomous driving, and navigation. This thesis seeks for developing novel approaches to generate vector maps from remote sensing images. To this end, we split the task into two sub-stages. The former stage consists in generating raster maps from remote sensing images by performing pixel-wise classification using advanced deep learning techniques. The latter stage aims at converting raster maps to vector ones by leveraging computational geometry approaches. This thesis addresses the challenges that are commonly encountered within both stages. Although previous research has shown that convolutional neural networks (CNNs)are able to generate excellent maps when training data are representative for test data, their performance significantly drops when there exists a large distribution difference between training and test images. In the first stage of our pipeline, we mainly aim atvercoming limited generalization abilities of CNNs to perform large-scale classification. We also explore a way of leveraging multiple data sets collected at different times with annotations for separate classes to train CNNs that can generate maps for all the classes. In the second part, we propose a method that vectorizes raster maps to integrate them into geographic information systems applications, which completes our processing pipeline. Throughout this thesis, we experiment on a large number of very high resolution satellite and aerial images. Our experiments demonstrate robustness and scalability of the proposed methods. Note de contenu : 1- Introduction
2- Progressively learning to segment new classes
3- City-to-city domain adaptation
4- Multi-source domain adaptation by data standardization
5- Multi-source, multi-target, and life-long domain adaptation
6- Vectorization of buildings via mesh approximation
7- Conclusions and perspectivesNuméro de notice : 28571 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Traitement du Signal et des Images : Côte d'Azur : 2020 Organisme de stage : INRIA Sophia Antipolis nature-HAL : Thèse En ligne : https://tel.archives-ouvertes.fr/tel-02989681v2/document Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97728 High-resolution aerial image labeling with convolutional neural networks / Emmanuel Maggiori in IEEE Transactions on geoscience and remote sensing, vol 55 n° 12 (December 2017)
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Titre : High-resolution aerial image labeling with convolutional neural networks Type de document : Article/Communication Auteurs : Emmanuel Maggiori, Auteur ; Yuliya Tarabalka, Auteur ; Guillaume Charpiat, Auteur ; Pierre Alliez, Auteur Année de publication : 2017 Article en page(s) : pp 7092 - 7103 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] image aérienne
[Termes IGN] indexation sémantique
[Termes IGN] inférence sémantique
[Termes IGN] réseau neuronal convolutifRésumé : (Auteur) The problem of dense semantic labeling consists in assigning semantic labels to every pixel in an image. In the context of aerial image analysis, it is particularly important to yield high-resolution outputs. In order to use convolutional neural networks (CNNs) for this task, it is required to design new specific architectures to provide fine-grained classification maps. Many dense semantic labeling CNNs have been recently proposed. Our first contribution is an in-depth analysis of these architectures. We establish the desired properties of an ideal semantic labeling CNN, and assess how those methods stand with regard to these properties. We observe that even though they provide competitive results, these CNNs often underexploit properties of semantic labeling that could lead to more effective and efficient architectures. Out of these observations, we then derive a CNN framework specifically adapted to the semantic labeling problem. In addition to learning features at different resolutions, it learns how to combine these features. By integrating local and global information in an efficient and flexible manner, it outperforms previous techniques. We evaluate the proposed framework and compare it with state-of-the-art architectures on public benchmarks of high-resolution aerial image labeling. Numéro de notice : A2017-769 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2017.2740362 En ligne : https://doi.org/10.1109/TGRS.2017.2740362 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88808
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 12 (December 2017) . - pp 7092 - 7103[article]Culture 3D cloud: A cloud computing platform for 3D scanning, documentation, preservation and dissemination of cultural heritage / Pierre Alliez in ERCIM News, n° 111 (October 2017)
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[article]
Titre : Culture 3D cloud: A cloud computing platform for 3D scanning, documentation, preservation and dissemination of cultural heritage Type de document : Article/Communication Auteurs : Pierre Alliez, Auteur ; François Forge, Auteur ; Livio de Luca, Auteur ; Marc Pierrot-Deseilligny , Auteur ; Marius Preda, Auteur
Année de publication : 2017 Article en page(s) : pp 35 - 35 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] base de données localisées 3D
[Termes IGN] informatique en nuage
[Termes IGN] patrimoine culturel
[Termes IGN] patrimoine immobilier
[Termes IGN] plateforme logicielleRésumé : (auteur) One of the limitations of the 3D digitisation process is that it typically requires highly specialised skills andyields heterogeneous results depending on proprietary software solutions and trial-and-error practices. Themain objective of Culture 3D Cloud [L1], a collaborative project funded within the framework of the French“Investissements d’Avenir” programme, is to overcome this limitation, providing the cultural community witha novel image-based modelling service for 3D digitisation of cultural artefacts. This will be achieved byleveraging the widespread expert knowledge of digital photography in the cultural arena to enable culturalheritage practitioners to perform routine 3D digitisation via photo-modelling. Cloud computing was chosenfor its capability to offer high computing resources at reasonable cost, scalable storage via continuouslygrowing virtual containers, multi-support diffusion via remote rendering and efficient deployment of releases. Numéro de notice : A2017-680 Affiliation des auteurs : LASTIG LOEMI+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtSansCL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97385
in ERCIM News > n° 111 (October 2017) . - pp 35 - 35[article]Documents numériques
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Culture 3D Cloud - pdf éditeurAdobe Acrobat PDFRecurrent neural networks to correct satellite image classification maps / Emmanuel Maggiori in IEEE Transactions on geoscience and remote sensing, vol 55 n° 9 (September 2017)
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[article]
Titre : Recurrent neural networks to correct satellite image classification maps Type de document : Article/Communication Auteurs : Emmanuel Maggiori, Auteur ; Guillaume Charpiat, Auteur ; Yuliya Tarabalka, Auteur ; Pierre Alliez, Auteur Année de publication : 2017 Article en page(s) : pp 4962 - 4971 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] apprentissage automatique
[Termes IGN] classification par réseau neuronal
[Termes IGN] convolution (signal)
[Termes IGN] itération
[Termes IGN] réseau neuronal convolutifRésumé : (Auteur) While initially devised for image categorization, convolutional neural networks (CNNs) are being increasingly used for the pixelwise semantic labeling of images. However, the proper nature of the most common CNN architectures makes them good at recognizing but poor at localizing objects precisely. This problem is magnified in the context of aerial and satellite image labeling, where a spatially fine object outlining is of paramount importance. Different iterative enhancement algorithms have been presented in the literature to progressively improve the coarse CNN outputs, seeking to sharpen object boundaries around real image edges. However, one must carefully design, choose, and tune such algorithms. Instead, our goal is to directly learn the iterative process itself. For this, we formulate a generic iterative enhancement process inspired from partial differential equations, and observe that it can be expressed as a recurrent neural network (RNN). Consequently, we train such a network from manually labeled data for our enhancement task. In a series of experiments, we show that our RNN effectively learns an iterative process that significantly improves the quality of satellite image classification maps. Numéro de notice : A2017-659 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2017.2697453 En ligne : http://dx.doi.org/10.1109/TGRS.2017.2697453 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=87070
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 9 (September 2017) . - pp 4962 - 4971[article]