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PKS: A photogrammetric key-frame selection method for visual-inertial systems built on ORB-SLAM3 / Arash Azimi in ISPRS Journal of photogrammetry and remote sensing, vol 191 (September 2022)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 191 (September 2022) . - pp 18 - 32 Titre : PKS: A photogrammetric key-frame selection method for visual-inertial systems built on ORB-SLAM3 Type de document : Article/Communication Auteurs : Arash Azimi, Auteur ; Ali Hosseininaveh Ahmadabadian, Auteur ; Fabio Remondino, Auteur Année de publication : 2022 Article en page(s) : pp 18 - 32 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie [Termes IGN] alignement [Termes IGN] cartographie et localisation simultanées [Termes IGN] centrale inertielle [Termes IGN] centre de gravité [Termes IGN] déformation d'image [Termes IGN] géoréférencement direct [Termes IGN] méthode heuristique [Termes IGN] semis de points [Termes IGN] seuillage d'image [Termes IGN] structure-from-motion [Termes IGN] vision par ordinateur Résumé : (auteur) Key-frame selection methods were developed in the past years to reduce the complexity of frame processing in visual odometry (VO) and visual simultaneous localization and mapping (VSLAM) algorithms. Key-frames help increasing algorithm's performances by sparsifying frames while maintaining its accuracy and robustness. Unlike current selection methods that rely on many heuristic thresholds to decide which key-frame should be selected, this paper proposes a photogrammetric-based key-frame selection method built upon ORB-SLAM3. The proposed algorithm, named Photogrammetric Key-frame Selection (PKS), replaces static heuristic thresholds with photogrammetric principles, ensuring algorithm’s robustness and better point cloud quality. A key-frame is chosen based on adaptive thresholds and the Equilibrium Of Center Of Gravity (ECOG) criteria as well as Inertial Measurement Unit (IMU) observations. To evaluate the proposed PKS method, the European Robotics Challenge (EuRoC) and an in-house datasets are used. Quantitative and qualitative evaluations are made by comparing trajectories, point clouds quality and completeness and Absolute Trajectory Error (ATE) in mono-inertial and stereo-inertial modes. Moreover, for the generated dense point clouds, extensive evaluations, including plane-fitting error, model deformation, model alignment error, and model density and quality, are performed. The results show that the proposed algorithm improves ORB-SLAM3 positioning accuracy by 18% in stereo-inertial mode and 20% in mono-inertial mode without the use of heuristic thresholds, as well as producing a more complete and accurate point cloud up to 50%. The open-source code of the presented method is available at https://github.com/arashazimi0032/PKS. Numéro de notice : A2022-664 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2022.07.003 Date de publication en ligne : 12/07/2022 En ligne : https://doi.org/10.1016/j.isprsjprs.2022.07.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101525 [article]

Applications and challenges of GRACE and GRACE follow-on satellite gravimetry / Jianli Chen in Surveys in Geophysics, vol 43 n° 1 (February 2022)  

Public [article]  inSurveys in Geophysics > vol 43 n° 1 (February 2022) . - pp 305 - 345 Titre : Applications and challenges of GRACE and GRACE follow-on satellite gravimetry Type de document : Article/Communication Auteurs : Jianli Chen, Auteur ; Anny Cazenave, Auteur ; Christoph Dahle, Auteur ; William Llovel, Auteur ; Isabelle Panet , Auteur ; Julia Pfeffer, Auteur ; Lorena Moreira, Auteur Année de publication : 2022 Projets : 3-projet - voir note / Article en page(s) : pp 305 - 345 Note générale : bibliographie This project received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (GRACEFUL Synergy Grant agreement No 855677). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse diachronique [Termes IGN] champ de gravitation [Termes IGN] champ de pesanteur terrestre [Termes IGN] changement climatique [Termes IGN] cryosphère [Termes IGN] détection de changement [Termes IGN] données GRACE [Termes IGN] gravimétrie spatiale [Termes IGN] hydrosphère [Termes IGN] masse [Termes IGN] niveau de la mer Résumé : (auteur) Time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) missions have opened up a new avenue of opportunities for studying large-scale mass redistribution and transport in the Earth system. Over the past 19 years, GRACE/GRACE-FO time-variable gravity measurements have been widely used to study mass variations in diferent components of the Earth system, including the hydrosphere, ocean, cryosphere, and solid Earth, and signifcantly improved our understanding of long-term variability of the climate system. We carry out a comprehensive review of GRACE/GRACE-FO satellite gravimetry, time-variable gravity felds, data processing methods, and major applications in several diferent felds, includingterrestrial water storage change, global ocean mass variation, ice sheets and glaciers mass balance, and deformation of the solid Earth. We discuss in detail several major challenges we need to face when using GRACE/GRACE-FO time-variable gravity measurements to study mass changes, and how we should address them. We also discuss the potential of satellite gravimetry in detecting gravitational changes that are believed to originate from the deep Earth. The extended record of GRACE/GRACE-FO gravity series, with expected continuous improvements in the coming years, will lead to a broader range of applications and improve our understanding of both climate change and the Earth system. Numéro de notice : A2022-113 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10712-021-09685-x Date de publication en ligne : 10/01/2022 En ligne : https://doi.org/10.1007/s10712-021-09685-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99631 [article]

Characterization of mass variations in Antarctica in response to climatic fluctuations from space-based gravimetry and radar altimetry data / Athul Kaitheri (2021)  

Public Titre : Characterization of mass variations in Antarctica in response to climatic fluctuations from space-based gravimetry and radar altimetry data Titre original : Caractérisation des variations de masse en Antarctique en réponse aux fluctuations climatiques à partir des données de gravimétrie spatiale et d’altimétrie radar Type de document : Thèse/HDR Auteurs : Athul Kaitheri, Auteur ; Anthony Mémin, Directeur de thèse ; Frédérique Rémy, Directeur de thèse Editeur : Nice : Université Côte d'Azur Année de publication : 2021 Importance : 138 p. Format : 21 x 30 cm Note générale : Bibliographie Thèse présentée en vue de l’obtention du grade de docteur de l'Université de Côte d'Azur, Spécialité Sciences de la Planète et de l'Univers Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] altimétrie satellitaire par radar [Termes IGN] analyse comparative [Termes IGN] Antarctique [Termes IGN] calotte glaciaire [Termes IGN] changement climatique [Termes IGN] données altimétriques [Termes IGN] données GRACE [Termes IGN] image Envisat [Termes IGN] levé gravimétrique [Termes IGN] masse [Termes IGN] oscillation [Termes IGN] régression Index. décimale : THESE Thèses et HDR Résumé : (Auteur) Quantifying the mass balance of the Antarctic Ice Sheet (AIS), and the resulting sea level rise, requires an understanding of inter-annual variability and associated causal mechanisms. This has become more complex and challenging in the backdrop of global climate change. Very few studies have been exploring the influence of climate anomalies on the AIS and only a vague estimate of its impact is available. Usually changes to the ice sheet are quantified using observations from space-borne altimetry and gravimetry missions. In this study, we use data from Envisat (2002 to 2010) and Gravity Recovery and Climate Experiment (GRACE) (2002 to 2016) missions to estimate monthly elevation changes and mass changes, respectively. Similar estimates of the changes are made using weather variables (surface mass balance (SMB) and temperature) from a regional climate model (RACMO2.3p2) as inputs to a firn compaction (FC) model. Using the firn compaction model we were able to model the transformation of snow into glacial ice and hence estimate changes in the elevation of the ice sheet using climate parameters. Elevation changes estimated from different techniques are in good agreement with each other across the AIS especially in West Antarctica, Antarctic Peninsula, and along the coasts of East Antarctica. Inter-annual height change patterns are then extracted using for the first time an empirical mode decomposition followed by a reconstruction of modes. These signal on applying least square method revealed a sub-4-year periodic signal in the all the three distinct height change patterns. This was indicative of the influence of the El Niño Southern Oscillation (ENSO), a climate anomaly that alters, among other parameters, moisture transport, sea surface temperature, precipitation, in and around the AIS at similar frequency by alternating between warm and cold conditions. But there existed altering periodic behavior among inter annual height change patterns in the Antarctic Pacific (AP) sector which was found possibly by the influence of multiple climate drivers, like the Amundsen Sea Low (ASL) and the Southern Annular Mode (SAM). A combined analysis of the three distinct estimates using a PCA (principal component analysis) along the coast revealed similar findings. Height change anomaly also appears to traverse eastwards from Coats Land to Pine Island Glacier (PIG) regions passing through Dronning Maud Land (DML) and Wilkes Land (WL) in 6 to 8 years. This is indicative of climate anomaly traversal due to the Antarctic Circumpolar Wave (ACW) which propagates anomalies through the Southern Ocean in 8 to 10 years. Altogether, inter-annual variability in the SMB of the AIS is found to be modulated by multiple competing climate anomalies. Note de contenu : 1. Introduction 1.1 Climate change scenario 1.2 Antarctica 1.3 Thesis overview 2. Height changes from satellite observations 2.1 Observations 2.2 Satellite gravimetry 2.3 Satellite altimetry 3. Height changes from modelling 3.1 Climate Model 3.2 Height changes from RACMO2.3p2 outputs 3.3 Firn densification model 4. Inter-annual variability 4.1 Comparison between height changes 4.2 Extraction of inter annual signals 4.3 Characterizing inter-annual signals 4.4 Principal component analysis 5. Influence of climate anomalies 5.1 El Ni˜no Southern Oscillation 5.2 Southern Annular Mode 5.3 Amundsen Sea Low 5.4 Antarctic Circumpolar Wave 6. General conclusions 6.1 Conclusions 6.2 Future perspectives Numéro de notice : 26825 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Thèse française Note de thèse : Thèse de doctorat : Sciences de la Planète et de l'Univers : Côte d'Azur : 2021 Organisme de stage : Géoazur nature-HAL : Thèse DOI : sans Date de publication en ligne : 19/04/2022 En ligne : https://tel.hal.science/tel-03644306/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100655

Tephra mass eruption rate from ground-based X-band and L-band microwave radars during the November 23, 2013, Etna Paroxysm / Frank S. Marzano in IEEE Transactions on geoscience and remote sensing, vol 58 n° 5 (May 2020)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 58 n° 5 (May 2020) . - pp 3314 - 3327 Titre : Tephra mass eruption rate from ground-based X-band and L-band microwave radars during the November 23, 2013, Etna Paroxysm Type de document : Article/Communication Auteurs : Frank S. Marzano, Auteur ; Luigi Mereu, Auteur ; Simona Scollo, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 3314 - 3327 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection [Termes IGN] bande L [Termes IGN] bande X [Termes IGN] capteur terrestre [Termes IGN] éruption volcanique [Termes IGN] Etna (volcan) [Termes IGN] lave [Termes IGN] masse [Termes IGN] micro-onde [Termes IGN] radar à antenne synthétique [Termes IGN] rayonnement infrarouge thermique [Termes IGN] surveillance géologique [Termes IGN] volcanologie Résumé : (auteur) The morning of November 23, 2013, a lava fountain formed from the New South-East Crater (NSEC) of Mt. Etna (Italy), one of the most active volcanoes in Europe. The explosive activity was observed from two ground-based radars, the X-band polarimetric scanning and the L-band Doppler fixed-pointing, as well as from a thermal-infrared camera. Taking advantage of the capability of the microwave radars to probe the volcanic plume and extending the volcanic ash radar retrieval (VARR) methodology, we estimate the mass eruption rate (MER) using three main techniques, namely surface-flux approach (SFA), mass continuity-based approach (MCA), and top-plume approach (TPA), as well as provide a quantitative evaluation of their uncertainty. Estimated exit velocities are between 160 and 230 m/s in the paroxysmal phase. The intercomparison between the SFA, MCA, and TPA methods, in terms of retrieved MER, shows a fairly good consistency with values up to $2.4\times 10^{6}$ kg/s. The estimated total erupted mass (TEM) is $3.8\times 10^{9}$ , $3.9\times 10^{9}$ , and $4.7\times 10^{9}$ kg for SFA with L-band, X-band, and thermal-infrared camera, respectively. Estimated TEM is between $1.7\times 10^{9}$ kg and $4.3\times 10^{9}$ for TPA methods and $3.9\times 10^{9}$ kg for the MCA technique. The SFA, MCA, and TPA results for TEM are in fairly good agreement with independent evaluations derived from ground collection of tephra deposit and estimated to be between $1.3\,\,\pm \,\,1.1\times 10^{9}$ and $5.7\times 10^{9}$ kg. This article shows that complementary strategies of ground-based remote sensing systems can provide an accurate real-time monitoring of a volcanic explosive activity. Numéro de notice : A2020-236 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2019.2953167 Date de publication en ligne : 23/12/2019 En ligne : https://doi.org/10.1109/TGRS.2019.2953167 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94982 [article]

How IGN (France) computed the so-called "centre of gravity" of physical Europe in 1989 and 2004 / Jean-François Hangouët (2019)  

Public contenu dans ArXiv / Université Cornell (Etats-Unis) (1991)   Titre : How IGN (France) computed the so-called "centre of gravity" of physical Europe in 1989 and 2004 Type de document : Article/Communication Auteurs : Jean-François Hangouët , Auteur Editeur : Ithaca [New York - Etats-Unis] : ArXiv - Université Cornell Année de publication : 2019 Importance : 5 p. Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] aplatissement [Termes IGN] centre de gravité [Termes IGN] ellipsoïde international [Termes IGN] épistémologie [Termes IGN] Europe (géographie physique) [Termes IGN] Institut national de l'information géographique et forestière (France) [Termes IGN] sphèroïde Résumé : (auteur) The method used by senior geodetic engineer Jean-Georges Affholder to determine what can be termed as the ‘centre of gravity’ of physical Europe in 1989 and 2004 relies on mathematical formulae which, in their only published version, happen to be flawed with typographical errors that do not reflect Mr. Affholder’s actual mathematical exactness. This short epistemological paper summarizes the major steps of Affholder’s method, provides a corrected version of the general formulae, and briefly recalls some particulars of the specific determination of the centre of gravity of physical Europe. Numéro de notice : P2019-005 Affiliation des auteurs : ENSG (2012-2019) Thématique : POSITIONNEMENT Nature : Preprint nature-HAL : Préprint DOI : 10.48550/arXiv.1910.04252 Date de publication en ligne : 08/10/2019 En ligne : https://doi.org/10.48550/arXiv.1910.04252 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93787

Mass variation observing system by high low inter-satellite links (MOBILE) : a new concept for sustained observation of mass transport from space / Roland Pail in Journal of geodetic science, vol 9 n° 1 (January 2019)  

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Gravity / Taher Zouaghi (2018)  

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Reducing leakage error in GRACE-observed long-term ice mass change: a case study in West Antarctica / J. L. Chen in Journal of geodesy, vol 89 n° 9 (september 2015)  

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Simplifying photogrammetric analysis for assessment of large mammal mass : automated targeting and 3D model building / L. Catherine Bester in Photogrammetric record, vol 30 n° 150 (June - August 2015)  

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La mission Rosetta et le calcul de gravité / Julien Laurent-Varin in XYZ, n° 142 (mars - mai 2015) 

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Nontidal ocean loading: amplitudes and potential effects in GPS height time series / Tonie M. van Dam in Journal of geodesy, vol 86 n° 11 (November 2012)  

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Rapport du directeur sur l'activité et la gestion du Bureau International des Poids et Mesures (BIPM), 1er juillet 2010 - 31 décembre 2011 / Bureau international des poids et mesures (2011)  

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Rapport du directeur sur l'activité et la gestion du Bureau International des Poids et Mesures (BIPM), 1er juillet 2009 - 30 juin 2010 / Bureau international des poids et mesures (2010)  

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Rapport du directeur sur l'activité et la gestion du Bureau international des poids et mesures (BIPM), 1er juillet 2008 - 30 juin 2009 / Bureau international des poids et mesures (2009)  

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Rapport du directeur sur l'activité et la gestion du Bureau International des Poids et Mesures (BIPM), 1er juillet 2007 - 30 juin 2008 / Bureau international des poids et mesures (2008)  

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