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Automatic segmentation of urban point clouds based on the gaussian map / Yinghui Wang in Photogrammetric record, vol 28 n° 144 (December 2013 - February 2014)  

Public [article]  inPhotogrammetric record > vol 28 n° 144 (December 2013 - February 2014) . - pp 342 - 361 Titre : Automatic segmentation of urban point clouds based on the gaussian map Type de document : Article/Communication Auteurs : Yinghui Wang, Auteur ; Wen Hao, Auteur ; Xiaojuan Ning, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 342 - 361 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] courbe de Gauss [Termes IGN] milieu urbain [Termes IGN] regroupement de points [Termes IGN] segmentation [Termes IGN] semis de points Résumé : (Auteur) A comprehensive method to segment urban point clouds based on the Gaussian map is presented. The normals of point clouds are firstly mapped to the Gaussian sphere and then partitioned into groups using a mean shift clustering algorithm. Next, a distance-based clustering method is presented to tackle overlapping surfaces which avoids under-segmentation. Based on the properties of the Gaussian map and the geometric information of the points, primitive shapes such as planes, cylinders, cones and spheres are recognised. Trees, cars, street lights and other objects are then segmented by using the distance-based clustering method after removing the planes, cylinders, cones and spheres from the large urban scenes. Finally, a refinement process based on primitive shapes is implemented to improve the segmentation results which effectively avoids over-segmentation. Experimental results demonstrate that the proposed method can be used as a robust way to segment urban point clouds based on the Gaussian map. Numéro de notice : A2013-627 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12041 Date de publication en ligne : 09/12/2013 En ligne : https://doi.org/10.1111/phor.12041 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32763 [article]

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Generation and validation of high-resolution DEMs from Worldview-2 stereo data / Umut Gunes Sefercik in Photogrammetric record, vol 28 n° 144 (December 2013 - February 2014)  

Public [article]  inPhotogrammetric record > vol 28 n° 144 (December 2013 - February 2014) . - pp 362 - 374 Titre : Generation and validation of high-resolution DEMs from Worldview-2 stereo data Type de document : Article/Communication Auteurs : Umut Gunes Sefercik, Auteur ; Mehmet Alkan, Auteur ; Gurcan Buyusalih, Auteur ; Karsten Jacobsen, Auteur Année de publication : 2013 Article en page(s) : pp 362 - 374 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] image à haute résolution [Termes IGN] image multibande [Termes IGN] image panchromatique [Termes IGN] image Worldview [Termes IGN] Istanbul (Turquie) [Termes IGN] modèle numérique de surface [Termes IGN] modèle stéréoscopique Résumé : (Auteur) WorldView-2 (WV-2), whose panchromatic images have a 0·5 m ground sampling distance (GSD), was launched by DigitalGlobe in 2009. It is the first commercial satellite to offer 8-band multispectral imagery with 1·8 m resolution. Due to the off-nadir sensor rotation of WV-2, it is feasible to obtain stereo coverage. Digital elevation models (DEMs) have been created with three WV-2 stereopairs of northern Istanbul with different land types and one of these is comprehensively analysed in this study. A reference DEM, developed from large-scale aerial photogrammetric mapping, together with a lidar DEM and an overlapping neighbouring WV-2 DEM, are used for validation. The generated WV-2 DEM reached, after filtering and in open areas, a standard deviation in height of approximately 1·0 GSD. A higher number of discrepancies larger than 4 m exist than would be expected from a normal distribution, influencing the standard deviation more than the normalised median absolute deviation (NMAD). Numéro de notice : A2013-628 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12038 Date de publication en ligne : 23/10/2013 En ligne : https://doi.org/10.1111/phor.12038 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32764 [article]

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Recording complex structures using close range photogrammetry: The cathedral of Santiago De Compostela / Santiago Martinez in Photogrammetric record, vol 28 n° 144 (December 2013 - February 2014)  

Public [article]  inPhotogrammetric record > vol 28 n° 144 (December 2013 - February 2014) . - pp 375 - 395 Titre : Recording complex structures using close range photogrammetry: The cathedral of Santiago De Compostela Type de document : Article/Communication Auteurs : Santiago Martinez, Auteur ; Juan Ortiz, Auteur ; M. Luz Gil, Auteur ; M.teresa Rego, Auteur Année de publication : 2013 Article en page(s) : pp 375 - 395 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie terrestre [Termes IGN] acquisition d'images [Termes IGN] cathédrale [Termes IGN] coût [Termes IGN] Espagne [Termes IGN] Galice (Espagne) [Termes IGN] La Corogne (Espagne) [Termes IGN] lever des détails [Termes IGN] modèle numérique du bâti [Termes IGN] modélisation 3D [Termes IGN] objet géographique complexe [Termes IGN] patrimoine culturel [Termes IGN] patrimoine immobilier [Termes IGN] photogrammétrie architecturale [Termes IGN] toit [Termes IGN] tour (bâtiment) Résumé : (Auteur) This paper describes the photogrammetric 3D modelling of complex buildings using low-cost automatic image matching (AIM), consumer-grade digital cameras and low-altitude imagery. To verify the potential of this method, it was applied to the documentation of a specific case: the towers and roofs of the Cathedral of Santiago de Compostela in Spain, a UNESCO World Heritage Site. The design and development of a mechanism for coping with the elevation, based on telescopic masts, was essential. Models, orthophotos and plans have been obtained to determine and rigorously measure the geometry involved. Thereby it was possible to accurately record the materials and decorative elements based on the restitution of the granite stones. Furthermore, close range photogrammetry made the analysis and quantification of the inclination of the south tower possible. Numéro de notice : A2013-629 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12040 Date de publication en ligne : 09/12/2013 En ligne : https://doi.org/10.1111/phor.12040 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32765 [article]

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Bundle adjustment with and without damping / Niclas Börlin in Photogrammetric record, vol 28 n° 144 (December 2013 - February 2014)  

Public [article]  inPhotogrammetric record > vol 28 n° 144 (December 2013 - February 2014) . - pp 396 - 415 Titre : Bundle adjustment with and without damping Type de document : Article/Communication Auteurs : Niclas Börlin, Auteur ; Pierre Grussenmeyer, Auteur Année de publication : 2013 Article en page(s) : pp 396 - 415 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie terrestre [Termes IGN] algorithme de Gauss-Newton [Termes IGN] atténuation [Termes IGN] compensation par faisceaux [Termes IGN] compensation par moindres carrés [Termes IGN] photogrammétrie terrestre Résumé : (Auteur) The least squares adjustment (LSA) method is studied as an optimisation problem and shown to be equivalent to the undamped Gauss–Newton (GN) optimisation method. Three problem-independent damping modifications of the GN method are presented: the line search method of Armijo (GNA); the Levenberg–Marquardt algorithm (LM); and Levenberg–Marquardt with Powell dogleg (LMP). Furthermore, an additional problem-specific “veto” damping technique, based on the chirality condition, is suggested. In a perturbation study on a terrestrial bundle adjustment problem, the GNA and LMP methods with veto damping can increase the size of the pull-in region compared to the undamped method; the LM method showed less improvement. The results suggest that damped methods can, in many cases, provide a solution where undamped methods fail and should be available in any LSA software package. Matlab code for the algorithms discussed is available from the authors. Numéro de notice : A2013-630 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12037 Date de publication en ligne : 14/10/2013 En ligne : https://doi.org/10.1111/phor.12037 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32766 [article]

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Digital elevation quality derived from medium-format digital cameras / Peter T. Y. Shih in Photogrammetric record, vol 28 n° 144 (December 2013 - February 2014)  

Public [article]  inPhotogrammetric record > vol 28 n° 144 (December 2013 - February 2014) . - pp 416 - 435 Titre : Digital elevation quality derived from medium-format digital cameras Type de document : Article/Communication Auteurs : Peter T. Y. Shih, Auteur ; J.Y. Wu, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 416 - 435 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] appariement automatique [Termes IGN] chambre à moyen format [Termes IGN] données lidar [Termes IGN] modèle numérique de surface [Termes IGN] qualité des données [Termes IGN] semis de points Résumé : (Auteur) Medium-format digital cameras are a useful tool in airborne lidar missions to produce digital ortho-images. This study investigates the quality of digital elevation models (DEMs) and digital surface models (DSMs) derived from such cameras. An image-matching strategy is used to produce height information from highly overlapping images and the quality of the derived height information is analysed using synchronous lidar point clouds as the reference data. The evaluation focused on various types of land cover and DEM generation methods. The RMSE between lidar and image-derived height information for two datasets was 0·054% and 0·027% of the flying height in flat, bare-earth areas, but studies with manually edited vegetated areas using stereo photogrammetry revealed high uncertainties, especially in steep terrain. Numéro de notice : A2013-631 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12039 Date de publication en ligne : 09/12/2013 En ligne : https://doi.org/10.1111/phor.12039 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32767 [article]

Exemplaires(1)

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106-2013041	RAB	Revue	Centre de documentation	En réserve L003	Disponible