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Dynamic human body reconstruction and motion tracking with low-cost depth cameras / Kangkan Wang in The Visual Computer, vol 37 n° 3 (March 2021)  

Public [article]  inThe Visual Computer > vol 37 n° 3 (March 2021) . - pp 603 - 618 Titre : Dynamic human body reconstruction and motion tracking with low-cost depth cameras Type de document : Article/Communication Auteurs : Kangkan Wang, Auteur ; Guofeng Zhang, Auteur ; Jian Yang, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 603 - 618 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] appariement de formes [Termes IGN] déformation de projection [Termes IGN] données d'apprentissage [Termes IGN] filtrage spatiotemporel [Termes IGN] maillage [Termes IGN] modèle dynamique [Termes IGN] modélisation 3D [Termes IGN] mouvement [Termes IGN] objet mobile [Termes IGN] reconstruction d'objet [Termes IGN] squelettisation Résumé : (auteur) We present a novel approach for dynamic human body reconstruction and motion tracking using low-cost depth cameras. Our reconstruction system is able to produce a sequence of dynamic 3D human body models from the noisy input depth data. To accurately align the template model with noisy input data, we combine skeleton-driven deformation and mesh deformation techniques to enhance the registration robustness to depth missing, occlusions, and severe noise. In addition, a novel data-driven 3D human body model is introduced to efficiently reconstruct human body models with wide shape and pose variations only using a limited number of training databases with standard standing pose. We perform quantitative and qualitative experiments to evaluate our method and compare it with other methods for body reconstruction on both synthetic and real datasets. Experimental results demonstrate the effectiveness of the proposed approach. Numéro de notice : A2021-341 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s00371-020-01826-4 date de publication en ligne : 26/02/2020 En ligne : https://doi.org/10.1007/s00371-020-01826-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97579 [article]

Minimum-error world map projections defined by polydimensional meshes / Justin H. Kunimune in International journal of cartography, vol 7 n° 1 (March 2021)  

Public [article]  inInternational journal of cartography > vol 7 n° 1 (March 2021) . - pp 78 - 99 Titre : Minimum-error world map projections defined by polydimensional meshes Type de document : Article/Communication Auteurs : Justin H. Kunimune, Auteur Année de publication : 2021 Article en page(s) : pp 78 - 99 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections [Termes IGN] déformation de projection [Termes IGN] données multidimensionnelles [Termes IGN] interpolation [Termes IGN] maillage [Termes IGN] optimisation spatiale [Termes IGN] représentation cartographique Résumé : (Auteur) In order to transform the curved surface of the earth onto the planar surface of a map, some distortion must be introduced. Conventional map projections are defined by mathematical formulas, and are thereby limited in their ability to control that distortion by the complexity of those formulas. Piecewise map projections based on interpolation onto unstructured meshes have no such constraints, and can therefore create maps that are better suited to many use cases. A method using multi-dimensional optimization to optimize such map projections is presented here, and demonstrated by the generation of several new map projections. These map projections are presented as the Danseiji projections, along with their potential applications. Numéro de notice : A2021-183 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/23729333.2020.1824174 date de publication en ligne : 06/10/2020 En ligne : https://doi.org/10.1080/23729333.2020.1824174 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97110 [article]

Ambiguous use of geographical information systems for the rectification of large-scale geometric maps / Anders Wästfelt in Cartographic journal (the), Vol 57 n° 3 (August 2020)  

Public [article]  inCartographic journal (the) > Vol 57 n° 3 (August 2020) . - pp 209 - 220 Titre : Ambiguous use of geographical information systems for the rectification of large-scale geometric maps Type de document : Article/Communication Auteurs : Anders Wästfelt, Auteur Année de publication : 2020 Article en page(s) : pp 209 - 220 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] ArcGIS [Termes IGN] carte ancienne [Termes IGN] correction géométrique [Termes IGN] déformation de projection [Termes IGN] déformation géométrique [Termes IGN] erreur de mesure [Termes IGN] erreur géométrique [Termes IGN] grande échelle [Termes IGN] grille [Termes IGN] point [Termes IGN] qualité des données [Termes IGN] Suède [Termes IGN] système de coordonnées Résumé : (auteur) Unlike modern maps, geometric maps lack a coordinate system and contain unsystematic geometric inaccuracies. This paper illuminates four aspects concerning the problem of uniting geographical information technology with old geometric maps. These are as follows: first, the origin of and geometric qualities in the representation of objects in geometric maps; second, the distortions originating from measurement techniques; third, the assumption that it is possible to find points that are the same over time for rectification in Geographic Information System (GIS); and, fourth, the extrapolation of unsystematic geometric distortions when using GIS techniques without any knowledge of the present unsystematic distortions in a map. The article presents the background of Swedish geometric maps and a hypothetical example is used to present the principle problems of using GIS techniques to rectify geometric maps. The conclusion of the paper is that systematic and unsystematic geometric distortions need to be identified and handled separately. Numéro de notice : A2020-803 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2019.1660511 date de publication en ligne : 13/03/2020 En ligne : https://doi.org/10.1080/00087041.2019.1660511 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96761 [article]

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The influence of web maps and education on adolescents’ global-scale cognitive map / Lieselot Lapon in Cartographic journal (the), Vol 57 n° 3 (August 2020)  

Public [article]  inCartographic journal (the) > Vol 57 n° 3 (August 2020) . - pp 221 - 234 Titre : The influence of web maps and education on adolescents’ global-scale cognitive map Type de document : Article/Communication Auteurs : Lieselot Lapon, Auteur ; Philippe De Maeyer, Auteur ; Bart De Wit, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 221 - 234 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] acquisition de connaissances [Termes IGN] carte cognitive [Termes IGN] cartographie par internet [Termes IGN] déformation de projection [Termes IGN] éducation [Termes IGN] lecture de carte [Termes IGN] projection [Termes IGN] projection de Robinson [Termes IGN] projection Universal Transverse Mercator [Termes IGN] web mapping [Vedettes matières IGN] Cartologie Résumé : (auteur) Several factors influence the global-scale cognitive map. The use of school books, atlases and web maps all play an essential role in the development of geographical knowledge of adolescents. This research examines the impact of the educational system versus web maps on the adolescents’ mental map. Through a specially designed web application, university students and secondary school pupils estimated the real proportion of countries and continents compared to Europe. Participants with a more theoretical background or wider knowledge about map projections and its distortions estimated the real proportions more accurately. This research also found that the Robinson projection, commonly used in schoolbooks and atlases, is the best-known map projection among adolescents. However, the influence of web maps could not be proven since no Mercator effect was found. Education is of undeniable importance, and therefore, educational materials that encourage people to look more carefully and critically at maps should be further developed. Numéro de notice : A2020-804 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2019.1660512 date de publication en ligne : 02/03/2020 En ligne : https://doi.org/10.1080/00087041.2019.1660512 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96762 [article]

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Direct georeferencing of airborne LiDAR data in national coordinates / Yongjun Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 84 (October 2013)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 84 (October 2013) . - pp 43 - 51 Titre : Direct georeferencing of airborne LiDAR data in national coordinates Type de document : Article/Communication Auteurs : Yongjun Zhang, Auteur ; Xiang Shen, Auteur Année de publication : 2013 Article en page(s) : pp 43 - 51 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] Chine [Termes IGN] coordonnées géodésiques [Termes IGN] déformation de projection [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] géoréférencement direct [Termes IGN] orientation externe [Termes IGN] projection [Termes IGN] système de référence local [Termes IGN] transformation de coordonnées Résumé : (Auteur) The topographic mapping products of airborne light detection and ranging (LiDAR) are usually required in the national coordinates (i.e., using the national datum and a conformal map projection). Since the spatial scale of the national datum is usually slightly different from the World Geodetic System 1984 (WGS 84) datum, and the map projection frame is not Cartesian, the georeferencing process in the national coordinates is inevitably affected by various geometric distortions. In this paper, all the major direct georeferencing distortion factors in the national coordinates, including one 3D scale distortion (the datum scale factor distortion), one height distortion (the earth curvature distortion), two length distortions (the horizontal-to-geodesic length distortion and the geodesic-to-projected length distortion), and three angle distortions (the skew-normal distortion, the normal-section-to-geodesic distortion, and the arc-to-chord distortion) are identified and demonstrated in detail; and high-precision map projection correction formulas are provided for the direct georeferencing of the airborne LiDAR data. Given the high computational complexity of the high-precision map projection correction approach, some more approximate correction formulas are also derived for the practical calculations. The simulated experiments show that the magnitude of the datum scale distortion can reach several centimeters to decimeters for the low (e.g., 500 m) and high (e.g., 8000 m) flying heights, and therefore it always needs to be corrected. Our proposed practical map projection correction approach has better accuracy than Legat’s approach,1 but it needs 25% more computational cost. As the correction accuracy of Legat’s approach can meet the requirements of airborne LiDAR data with low and medium flight height (up to 3000 m above ground), our practical correction approach is more suitable to the high-altitude aerial imagery. The residuals of our proposed high-precision map projection correction approach are trivial even for the high flight height of 8000 m. It can be used for the theoretical applications such as the accurate evaluation of different GPS/INS attitude transformation methods to the national coordinates. Numéro de notice : A2013-516 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.07.003 date de publication en ligne : 01/08/2013 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.07.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32653 [article]

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Cours complémentaire de géodésien et d'astronomie 2ème année, 3. Troisième partie Théorie générale des projections / Georges Perrier (1922)

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