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Laser scanning in heritage documentation: The scanning pipeline and its challenges / H. Ruther in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 309 - 316 Titre : Laser scanning in heritage documentation: The scanning pipeline and its challenges Type de document : Article/Communication Auteurs : H. Ruther, Auteur ; R. Bhurtha, Auteur ; C. Held, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 309 - 316 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] Afrique du sud (état) [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] patrimoine culturel [Termes IGN] semis de points [Termes IGN] Tanzanie Résumé : (Auteur) In an attempt to show the complexity of terrestrial laser scanning of heritage sites and dispel the not infrequently found perception of a largely automated tool with close to real time processing capabilities, the individual steps of the data acquisition and processing pipeline, including registration, point cloud cleaning, surface reconstruction, hole filling, texturing and final output are discussed. Emphasized are areas in which further development and research are desirable. A brief discussion of the concepts and implementation of the African Cultural Heritage Sites and Landscapes Project, as executed by the Zamani Research Group at the University of Cape Town, is incorporated into the paper. This database integrates spatial and non-spatial data and focuses on architectural heritage sites and cultural landscapes. The spatial data comprises of 3D laser scans, GIS's for each site and its environment, stereo images, panoramas, ground plans, elevations and sections derived from laser scan models, contextual photography and videos as well as 3D landscape models. The database is primarily designed as a resource for research and higher education. However, the spatial data acquired for the project are presently used in a number of restoration and conservation projects. An important further objective is the creation of a permanent digital record. The project, funded by the Andrew W. Mellon Foundation, is a joint initiative of the Zamani Research Group at the University of Cape Town and JStor, New York. Numéro de notice : A2012-176 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.309 En ligne : https://doi.org/10.14358/PERS.78.4.309 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31623 [article]

Cell-based automatic deformation computation by analyzing terrestrial Lidar point clouds / J. Wu in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 317 - 329 Titre : Cell-based automatic deformation computation by analyzing terrestrial Lidar point clouds Type de document : Article/Communication Auteurs : J. Wu, Auteur ; P.Y. Gilliéron, Auteur ; Bertrand Merminod, Auteur Année de publication : 2012 Article en page(s) : pp 317 - 329 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] érosion [Termes IGN] lasergrammétrie [Termes IGN] modèle de déformation tectonique [Termes IGN] semis de points Résumé : (Auteur) This paper presents a cell-based approach for computing the deformation of a monitored object by analyzing point cloud data from terrestrial lidar. This approach can automatically generate an informative deformation description (called “deformation map”) with distinctive deformation characteristics for different partial areas. The approach consists of three major computing steps: (a) “split” - the space of the monitored object is divided into 3D uniform cells, (b) “detect” - deformation parameters for each cell (called “meta-deformation”) are estimated by comparing the point clouds in the cell sampled at Epochs I and II, and (c) “merge” - the adjacent cells with similar meta-deformation are combined together in a partial area with a consistent “sub-deformation.” The main contributions of this paper are: (a) a hybrid deformation model for incremental and comprehensive deformation representation, including metadeformation, sub-deformation and deformation map, (b) a systematic procedure of “split-detect-merge” to automatically and gradually estimate the hybrid deformation model, and (c) a complete validation with a couple of synthetic and real datasets. Numéro de notice : A2012-177 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.317 En ligne : https://doi.org/10.14358/PERS.78.4.317 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31624 [article]

Automatic extraction of road markings from mobile Lidar point clouds / B. Yang in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 331 - 338 Titre : Automatic extraction of road markings from mobile Lidar point clouds Type de document : Article/Communication Auteurs : B. Yang, Auteur ; Leyuan Fang, Auteur ; Qi Li, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 331 - 338 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] extraction automatique [Termes IGN] interpolation [Termes IGN] lasergrammétrie [Termes IGN] segmentation [Termes IGN] semis de points [Termes IGN] signalisation routière Résumé : (Auteur) Among implicit information of laser points, the strength of reflection of laser points is closely related to the property of road materials which helps detecting road markings. This paper presents a novel approach to automatically extracting road markings from mobile lidar point clouds. An interpolation method is first used to generate a georeferenced feature image of the point cloud, which helps to isolate the points of road surfaces. Then, an algorithm is used to separate these points within a range according to their strength of reflection. The separated points are further segmented to remove non-road points based on height threshold. Finally, the outlines of road markings are extracted from the segmented points using the semantic knowledge of road markings. The results demonstrated that our method was very promising for automatic extraction of road markings from lidar point clouds collected by a land-based mobile lidar system, an Optech Lynx Mobile Mapper. Numéro de notice : A2012-178 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.331 En ligne : https://doi.org/10.14358/PERS.78.4.331 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31625 [article]

Terrestrial laser scanning for delineating in-stream boulders and quantifying habitat complexity measures / J. Resop in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 363 - 371 Titre : Terrestrial laser scanning for delineating in-stream boulders and quantifying habitat complexity measures Type de document : Article/Communication Auteurs : J. Resop, Auteur ; J. Kozarek, Auteur ; W. Hession, Auteur Année de publication : 2012 Article en page(s) : pp 363 - 371 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse comparative [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] habitat animal [Termes IGN] rivière [Termes IGN] rocher [Termes IGN] tachéomètre électronique [Termes IGN] Virginie (Etats-Unis) Résumé : (Auteur) Accurate stream topography measurement is important for many ecological applications such as hydraulic modeling and habitat characterization. Habitat complexity measures are often made using visual approximations or total station (TS) surveying that can be subjective and have limited spatial resolution. Terrestrial laser scanning (TLS) can measure topography at a high resolution and accuracy. Two methods, TS surveying and TLS, were compared for measuring complex topography in a boulder-dominated 100 m forested reach of the Staunton River in Shenandoah National Park, Virginia. The mean absolute difference between the two datasets was 0.11 m with 82.3 percent of the TS data within _0.1 m of TLS. The TLS dataset was processed to remove vegetation and create a 2 cm digital elevation model (DEM). An algorithm was developed for delineating rocks within the stream channel from the DEM. A common ecological metric based on the structural complexity of the stream, percent in-stream rock cover, was calculated from the TLS dataset, and the results were compared to estimates from traditional methods. This application illustrates the potential of TLS to quantify habitat complexity measures in an automated, unbiased manner. Numéro de notice : A2012-179 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.363 En ligne : https://doi.org/10.14358/PERS.78.4.363 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31626 [article]

An efficient point cloud management method based on a 3D R-tree / J. Gong in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 373 - 381 Titre : An efficient point cloud management method based on a 3D R-tree Type de document : Article/Communication Auteurs : J. Gong, Auteur ; Q. Zhu, Auteur ; R. Zhong, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 373 - 381 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre-R [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] octree [Termes IGN] performance [Termes IGN] semis de points Résumé : (Auteur) Vehicle-borne laser-scanned point clouds have become increasingly important 3D data sources in fields such as digital city modeling and emergency response management. Aiming at reducing the technical bottlenecks of management and visualization of very large point cloud data sets, this paper proposes a new spatial organization method called 3DOR-Tree, which integrates Octree and 3D R-Tree data structures. This method utilizes Octree's rapid convergence to generate R-Tree leaf nodes, which are inserted directly into the R-Tree, thus avoiding time-consuming point-by-point insertion operations. Furthermore, this paper extends the R-Tree structure to support LOD (level of detail) models. Based on the extended structure, a practical data management method is presented. Finally, an adaptive control method for LODS of point clouds is illustrated. Typical experimental results show that our method possesses quasi-real-time index construction speed, a good storage utilization rate, and efficient visualization performance. Numéro de notice : A2012-180 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.373 En ligne : https://doi.org/10.14358/PERS.78.4.373 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31627 [article]

Tree topology representation from TLS point clouds using depth-first search in voxel space / A. Schilling in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 4 (April 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 4 (April 2012) . - pp 383 - 392 Titre : Tree topology representation from TLS point clouds using depth-first search in voxel space Type de document : Article/Communication Auteurs : A. Schilling, Auteur ; A. Schmidt, Auteur ; Hans-Gerd Maas, Auteur Année de publication : 2012 Article en page(s) : pp 383 - 392 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre (mathématique) [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] relation topologique [Termes IGN] semis de points [Termes IGN] transformation de Hough [Termes IGN] voxel Résumé : (Auteur) For a fundamental understanding of environmental processes and for the management of forests, information on the tree structure, preferably in 3D, is vital. Therefore, we propose a method to retrieve the spatial tree structure from 3D point clouds captured by a terrestrial laser scanner. The procedure addresses dense and noisy data sets of separate trees. Our method involves a variation of the Circular Hough Transform to determine trunk positions and a sequence of operations in voxel space. The core of the approach is the depth-first search algorithm, known from graph theory, to actually recover the tree as a graph. Furthermore, we compare results obtained from the tree graph to reference measurements of forest inventory parameters. The computation time of our method for topology representation is low and the method provides a reasonably accurate approximation of the 3D tree structure. Numéro de notice : A2012-181 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.4.383 En ligne : https://doi.org/10.14358/PERS.78.4.383 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31628 [article]