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GPS precise point positioning for UAV photogrammetry / Ben Grayson in Photogrammetric record, vol 33 n° 164 (December 2018)  

Public [article]  inPhotogrammetric record > vol 33 n° 164 (December 2018) . - pp 427 - 447 Titre : GPS precise point positioning for UAV photogrammetry Type de document : Article/Communication Auteurs : Ben Grayson, Auteur ; Nigel Penna, Auteur ; Jon P. Mills, Auteur ; Darion S. Grant, Auteur Année de publication : 2018 Article en page(s) : pp 427 - 447 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] compensation par faisceaux [Termes IGN] géoréférencement direct [Termes IGN] image captée par drone [Termes IGN] positionnement ponctuel précis [Termes IGN] structure-from-motion Résumé : (Auteur) The use of Global Positioning System (GPS) precise point positioning (PPP) on a fixed‐wing unmanned aerial vehicle (UAV) is demonstrated for photogrammetric mapping at accuracies of centimetres in planimetry and about a decimetre in height, from flights of 25 to 30 minutes in duration. The GPS PPP estimated camera station positions are used to constrain estimates of image positions in the photogrammetric bundle block adjustment, as with relative GPS positioning. GPS PPP alleviates all spatial operating constraints associated with the installation and the use of ground control points, a local ground GPS reference station or the need to operate within the bounds of a permanent GPS reference station network. This simplifies operational logistics and enables large‐scale photogrammetric mapping from UAVs in even the most remote and challenging geographic locations. Numéro de notice : A2018-621 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/phor.12259 Date de publication en ligne : 05/11/2018 En ligne : https://doi.org/10.1111/phor.12259 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92865 [article]

A greyscale voxel model for airborne lidar data applied to building detection / Liying Wang in Photogrammetric record, vol 33 n° 164 (December 2018)  

Public [article]  inPhotogrammetric record > vol 33 n° 164 (December 2018) . - pp 470 - 490 Titre : A greyscale voxel model for airborne lidar data applied to building detection Type de document : Article/Communication Auteurs : Liying Wang, Auteur ; Yuanding Zhao, Auteur ; Yu Li, Auteur Année de publication : 2018 Article en page(s) : pp 470 - 490 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection du bâti [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] niveau de gris (image) [Termes IGN] semis de points [Termes IGN] toit [Termes IGN] voxel Résumé : (Auteur) The existing binary voxel model algorithm for 3D building detection (3BD) from airborne lidar cannot distinguish between connected buildings and non‐buildings. As a result, a greyscale voxel structure model, using the discretised mean intensity of lidar points, is presented to support subsequent building detection in areas where buildings are adjacent to non‐buildings but with different greyscales. The resulting 3BD algorithm first detects a building roof by selecting voxels characterised by a jump in elevation as seeds, labelling them and their 3D connected regions as rooftop voxels. Then voxels which fall into buffers and possess similar greyscales to that of the corresponding building outline are assigned as building façades. The results for detected buildings are evaluated using lidar data with different densities and demonstrate a high rate of success. Numéro de notice : A2018-622 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/phor.12266 Date de publication en ligne : 10/01/2019 En ligne : https://doi.org/10.1111/phor.12266 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92866 [article]