Descripteur
Documents disponibles dans cette catégorie (110)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Local Moebius transformations applied to omnidirectional images / Leonardo Souto Ferreira in Computers and graphics, vol 68 (November 2017)
[article]
Titre : Local Moebius transformations applied to omnidirectional images Type de document : Article/Communication Auteurs : Leonardo Souto Ferreira, Auteur ; Leonardo Sacht, Auteur ; Luiz Velho, Auteur Année de publication : 2017 Article en page(s) : pp 77 - 83 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] image terrestre
[Termes IGN] pondération
[Termes IGN] zone d'intérêtRésumé : (auteur) This work presents a new method to transform omnidirectional images based on a combination of Moebius transformations in the complex plane and weighting functions that restrict the action of these mappings to regions of interest. The transformations are calculated based on the specification of the image of three points and the weighting functions are designed to achieve specific goals such as local zoom or straight line rectification. Since no optimization or numerical methods are involved, our implementation of the proposed method can be upgraded to reach real-time performance. We provide a user interface and present many results that illustrate the potential of the proposed technique. Numéro de notice : A2017-558 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.cag.2017.08.005 En ligne : https://doi.org/10.1016/j.cag.2017.08.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86634
in Computers and graphics > vol 68 (November 2017) . - pp 77 - 83[article]Automatic measurement of control points for aerial image orientation / Adilson Berveglieri in Photogrammetric record, vol 32 n° 158 (June - july 2017)
[article]
Titre : Automatic measurement of control points for aerial image orientation Type de document : Article/Communication Auteurs : Adilson Berveglieri, Auteur ; Antonio Maria Garcia Tommaselli, Auteur Année de publication : 2017 Article en page(s) : pp 141 - 159 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] appariement d'images
[Termes IGN] calcul automatique
[Termes IGN] compensation par bloc
[Termes IGN] image aérienne
[Termes IGN] image terrestre
[Termes IGN] objectif grand angulaire
[Termes IGN] orientation d'image
[Termes IGN] point d'appui
[Termes IGN] précision des mesuresRésumé : (Auteur) This paper presents an automatic workflow for measuring natural ground control points (GCPs) in aerial images. The approach is based on the acquisition of multi-scale fisheye vertical terrestrial images over distinguishable areas to automatically generate georeferenced image patches. These are matched with aerial images using correspondence techniques and then used as ground control. The technique was assessed using a bundle block adjustment, indicating an accuracy based on check points of approximately 1/5 of the ground sample distance (GSD) in planimetry and 1 GSD in elevation. Automatic GCP measurements thus improved the final accuracy in comparison with manual measurement. Numéro de notice : A2017-362 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12190 En ligne : http:dx.doi.org/10.1111/phor.12190 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85773
in Photogrammetric record > vol 32 n° 158 (June - july 2017) . - pp 141 - 159[article]Urban 3D segmentation and modelling from street view images and LiDAR point clouds / Pouria Babahajiani in Machine Vision and Applications, sans n° ([01/06/2017])
[article]
Titre : Urban 3D segmentation and modelling from street view images and LiDAR point clouds Type de document : Article/Communication Auteurs : Pouria Babahajiani, Auteur ; Lixin Fan, Auteur ; Joni-Kristian Kämäräinen, Auteur ; Moncef Gabbouj, Auteur Année de publication : 2017 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] base de données urbaines
[Termes IGN] cartographie urbaine
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] façade
[Termes IGN] image terrestre
[Termes IGN] milieu urbain
[Termes IGN] segmentation sémantique
[Termes IGN] semis de pointsRésumé : (auteur) 3D urban maps with semantic labels and metric information are not only essential for the next generation robots such autonomous vehicles and city drones, but also help to visualize and augment local environment in mobile user applications. The machine vision challenge is to generate accurate urban maps from existing data with minimal manual annotation. In this work, we propose a novel methodology that takes GPS registered LiDAR (Light Detection And Ranging) point clouds and street view images as inputs and creates semantic labels for the 3D points clouds using a hybrid of rule-based parsing and learning-based labelling that combine point cloud and photometric features. The rule-based parsing boosts segmentation of simple and large structures such as street surfaces and building facades that span almost 75% of the point cloud data. For more complex structures, such as cars, trees and pedestrians, we adopt boosted decision trees that exploit both structure (LiDAR) and photometric (street view) features. We provide qualitative examples of our methodology in 3D visualization where we construct parametric graphical models from labelled data and in 2D image segmentation where 3D labels are back projected to the street view images. In quantitative evaluation we report classification accuracy and computing times and compare results to competing methods with three popular databases: NAVTEQ True, Paris-Rue-Madame and TLS (terrestrial laser scanned) Velodyne. Numéro de notice : A2017-255 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Article DOI : 10.1007/s00138-017-0845-3 En ligne : https://doi.org/10.1007/s00138-017-0845-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85269
in Machine Vision and Applications > sans n° [01/06/2017][article]
Titre : Monitoring rock glaciers by combining photogrammetric and GNSS-based methods Type de document : Thèse/HDR Auteurs : Fabian Neyer, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2017 Autre Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 99 Importance : 174 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-45-1 Note générale : bibliographie
thesis submitted to attain the degree of doctor of sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] Alpes centrales
[Termes IGN] champ de vitesse
[Termes IGN] collocation par moindres carrés
[Termes IGN] déformation de la croute terrestre
[Termes IGN] données localisées 3D
[Termes IGN] glacier
[Termes IGN] image terrestre
[Termes IGN] matrice de covariance
[Termes IGN] pergélisol
[Termes IGN] reconstruction 3D
[Termes IGN] rocher
[Termes IGN] série temporelle
[Termes IGN] SuisseIndex. décimale : 30.60 Géodésie spatiale Résumé : (auteur) Rock glaciers are creeping landforms of perennially frozen ground and belong to the permafrost creeping phenomena. They are mainly composed of rock debris that accumulate in areas of high natural erosion. Ice particles between the rocks cause the moving accumulation in steep terrain to dynamically flow downslope. In the Alpine region, these morphological landforms mainly occur at north-facing mountain slopes in high altitudes above the forest boundary and are known for their sensitivity to climate change.
For several decades, rock glaciers have been monitored for scientific aims, while advances in surveying technologies increased the interest in such studies since the 1990s. Modern technologies in remote sensing (e.g., airborne imagery or satellite-based measurement techniques) are often combined with measurements from field campaigns, i.e., measurements taken directly on a rock glacier (e.g., GNSS, laser-scanning, ground temperature measurements, etc). The high-level goal is to enhance the process understanding, especially with respect to the changing climate: various studies indicate an extended risk of slope failures in steep frozen bedrock due to the global temperature increase. Early recognition of increased activities help to inform local authorities in the endangered areas about the potential hazard before such an event.
The present work is part of the X-Sense project (Nano-Tera.ch), with an interdisciplinary team of scientists that build and operate new low-cost devices for data acquisition, develop new data processing pipelines and algorithms for evaluation, and also gain new insight of natural processes in these regions. Autonomous measurement systems, developed within other work packages in the X-Sense project, observe different permafrost creep areas with high resolution in space and time. Combined with multi-year observations, the derived surface motions are used to obtain an improved process understanding.
This work focuses on the photogrammetric image processing in order to retrieve precise surface displacement estimates. More precisely, image sequences, acquired with two permanently installed commercial digital single-reflex cameras, are used to measure topographic changes in the observed permafrost area. By the combination with high resolution GNSS positioning results, the goal is to obtain precise time series of moving rock boulders at different positions within the field of view. Challenges arising from the combination of different data sets, the development of an automatic processing pipeline, and an improvement of the processing strategy in general, are the main tasks of this thesis.
The study site is the bordering area above the Grabengufer rock glacier (Mattervalley VS, Switzerland), known as the Grabengufer rock slide. Local topographic conditions allowed only a partially good installation geometry for the photogrammetric reconstruction. With respect to a 3D reconstruction without the use of GNSS coordinates, an accuracy increase of about one order of magnitude could be achieved in case these high-precision solutions were integrated. More specifically, respective standard deviations for the East, North, and Height components of 6, 5, and 2 cm were achieved. The stated accuracy, maintained throughout the measurement period of nearly four years (summer months), was obtained in an area of approximately 80m×80 m, with a mean distance of 80 m from the two cameras.
Position time series of moving rock boulders were filtered using the principles of collocation. Analyzing the correlation characteristics of the stochastic signal, an optimal correlation length was computed and used to extract relevant signals from the noise contaminated time series. Velocity was directly estimated as a derived quantity in the collocation process. Furthermore, the techniques of the adaptive collocation approach is presented. This iterative method uses the principles of a dynamically adjusting anisotropic covariance metric. In an example of 2-dimensional velocity fields it is shown that regional compression and extension areas can be extracted.
Results indicate that the observed permafrost area has experienced a mean annual acceleration of about 0.1m/Year between the years 2013 and 2015. During the late summer months of 2015, a prominent temporal acceleration was observed. The mean displacement rate was found to be 0.67m/year, whereas the 3-dimensional displacement is dominated by a translation following the gliding surface. An area in the front of the observed field of view was found to have higher displacement rates, especially during the late summer months, thus it detaches from the otherwise relatively homogeneous flow field.
The methods and principles presented in this work show the potential of monitoring permafrost surface displacements using permanently installed optical cameras in combination with positioning results from permanently mounted GNSS stations. These principles can easily be transfered to other monitoring applications and thus contribute to a better understanding of such processes.Note de contenu : 1 Introduction
2 Study Site
3 Image-Based Displacement Estimation
4 Object Point Reconstruction
5 Collocation for Time Series Analysis
6 Results
7 Conclusions
8 OutlookNuméro de notice : 17458 Affiliation des auteurs : non IGN Autre URL associée : https://doi.org/10.3929/ethz-a-010865360 Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : thèse : Sciences : ETHZ : 2016 DOI : 10.3929/ethz-a-010865360 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-99.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89683 Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 17458-01 33.60 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible SVM et réseaux neuronaux convolutifs pour la classification de scènes urbaines / Amaury Zarzelli (2017)
Titre : SVM et réseaux neuronaux convolutifs pour la classification de scènes urbaines Type de document : Mémoire Auteurs : Amaury Zarzelli, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2017 Importance : 42 p. Format : 21 x 30 cm Note générale : Bibliographie
Rapport de projet pluridisciplinaire, cycle Ingénieur 2e annéeLangues : Français (fre) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] carte thématique
[Termes IGN] classification par réseau neuronal
[Termes IGN] classification par séparateurs à vaste marge
[Termes IGN] image Streetview
[Termes IGN] Ottawa
[Termes IGN] régression
[Termes IGN] réseau neuronal convolutif
[Termes IGN] scène urbaineIndex. décimale : PROJET Mémoires : Rapports de projet - stage des ingénieurs de 2e année Résumé : (Auteur) L’accès de plus en plus répandu à des banques de données d’imagerie urbaine telles que StreetView de Google en corrélation avec le progrès des technologies en apprentissage machine facilite le développement de techniques permettant le traitement automatique des caractéristiques physiques du bâti sur de grandes zones urbaines. L’une des applications de ce traitement peut être l’étude sociologique, et notamment la mesure de la gentrification, processus par lequel des classes aisées s’installent dans des quartiers historiquement moins favorisés. En effet, ce phénomène se caractérise souvent par une modification de l’aspect des habitations, qui peut être détectée par un modèle de classification. Ce projet consiste à traiter toutes les étapes de cette classification, du téléchargement de l’imagerie urbaine jusqu’à la cartographie du phénomène étudié et peut être adapté à la qualification de n’importe quel phénomène urbain (accessibilité pour les piétons, structure des bâtiments…). Je me suis en particulier attaché à l’étape de la conception du modèle, en explorant notamment des techniques innovantes basées sur des réseaux de neurones convolutifs et dont les résultats sont prometteurs. Le travail a été effectué sur l’unité urbaine de la ville d’Ottawa au Canada. L’ensemble des travaux réalisés au cours du projet sont accessibles sur le dépôt GitHub suivant : https://github.com/azarz/gentriNet. Note de contenu : INTRODUCTION
1. Gestion de projet
2. Étapes de la classification
3. Résultats obtenus
CONCLUSIONNuméro de notice : 22806 Affiliation des auteurs : IGN (2012-2019) Thématique : IMAGERIE/INFORMATIQUE/MATHEMATIQUE/URBANISME Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Université d’Ottawa Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88412 Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 22806-01 PROJET Livre Centre de documentation Travaux d'élèves Disponible Documents numériques
peut être téléchargé
SVM et réseaux neuronaux convolutifsAdobe Acrobat PDF Télédétection pour l'observation des surfaces continentales, Ch. 2. Analyse de scènes urbaines avec un véhicule de cartographie mobile / Bruno Vallet (2017)PermalinkBundle adjustment of spherical images acquired with a portable panoramic image mapping system (PPIMS) / Yi-Hsing Tseng in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 12 (December 2016)PermalinkImage-based mobile mapping for 3D Urban data capture / Stefan Cavegn in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 12 (December 2016)PermalinkMapillary and the power of community mapping / Peter Neubauer in Geoinformatics, vol 18 n° 8 (December 2015)PermalinkComment la photographie peut devenir un outil technique pour le forestier / Olivier Martineau in Forêt entreprise, n° 225 (novembre-décembre 2015)PermalinkA historical timber frame model for diagnosis and documentation before building restoration / Mathieu Koehl in International journal of 3-D information modeling, vol 4 n° 4 (October - December 2015)PermalinkExtracting mobile objects in images using a Velodyne lidar point cloud / Bruno Vallet in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol II-3 W4 (March 2015)PermalinkPermalinkMethod for orthorectification of terrestrial radar maps / Marion Jaud in ISPRS Journal of photogrammetry and remote sensing, vol 97 (November 2014)PermalinkSequential digital elevation models of active lava flows from ground-based stereo time-lapse imagery / M.R. James in ISPRS Journal of photogrammetry and remote sensing, vol 97 (November 2014)Permalink