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Efficiently annotating object images with absolute size information using mobile devices / Martin Hofmann in International journal of computer vision, vol 127 n° 2 (February 2019)  

Public [article]  inInternational journal of computer vision > vol 127 n° 2 (February 2019) . - pp 207 - 224 Titre : Efficiently annotating object images with absolute size information using mobile devices Type de document : Article/Communication Auteurs : Martin Hofmann, Auteur ; Marco Seeland, Auteur ; Patrick Mäder, Auteur Année de publication : 2019 Article en page(s) : pp 207 - 224 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] appareil portable [Termes IGN] appariement automatique [Termes IGN] image numérique [Termes IGN] longueur focale Résumé : (Auteur) The projection of a real world scenery to a planar image sensor inherits the loss of information about the 3D structure as well as the absolute dimensions of the scene. For image analysis and object classification tasks, however, absolute size information can make results more accurate. Today, the creation of size annotated image datasets is effort intensive and typically requires measurement equipment not available to public image contributors. In this paper, we propose an effective annotation method that utilizes the camera within smart mobile devices to capture the missing size information along with the image. The approach builds on the fact that with a camera, calibrated to a specific object distance, lengths can be measured in the object’s plane. We use the camera’s minimum focus distance as calibration distance and propose an adaptive feature matching process for precise computation of the scale change between two images facilitating measurements on larger object distances. Eventually, the measured object is segmented and its size information is annotated for later analysis. A user study showed that humans are able to retrieve the calibration distance with a low variance. The proposed approach facilitates a measurement accuracy comparable to manual measurement with a ruler and outperforms state-of-the-art methods in terms of accuracy and repeatability. Consequently, the proposed method allows in-situ size annotation of objects in images without the need for additional equipment or an artificial reference object in the scene. Numéro de notice : A2018-600 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s11263-018-1093-3 Date de publication en ligne : 24/05/2018 En ligne : https://doi.org/10.1007/s11263-018-1093-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92527 [article]

Indoor positioning using differential Wi-Fi lateration / Guenther Retscher in Journal of applied geodesy, vol 11 n° 4 (December 2017)  

Public [article]  inJournal of applied geodesy > vol 11 n° 4 (December 2017) . - pp 249 - 269 Titre : Indoor positioning using differential Wi-Fi lateration Type de document : Article/Communication Auteurs : Guenther Retscher, Auteur ; Thomas Tatschl, Auteur Année de publication : 2017 Article en page(s) : pp 249 - 269 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] appareil portable [Termes IGN] multilatération [Termes IGN] positionnement en intérieur [Termes IGN] positionnement par WiFi Résumé : (Auteur) For Wi-Fi positioning usually location fingerprinting or (tri)lateration are employed whereby the received signal strengths (RSSs) of the surrounding Wi-Fi Access Points (APs) are scanned on the mobile devices and used to perform localization. Within the scope of this study, the position of a mobile user is determined on the basis of lateration. Two new differential approaches are developed and compared to two common models, i.e., the one-slope and multi-wall model, for the conversion of the measured RSS of the Wi-Fi signals into ranges. The two novel methods are termed DWi-Fi as they are derived either from the well-known DGPS or VLBI positioning principles. They make use of a network of reference stations deployed in the area of interest. From continuous RSS observations on these reference stations correction parameters are derived and applied by the user in real-time. This approach leads to a reduced influence of temporal and spatial variations and various propagation effects on the positioning result. In practical use cases conducted in a multi-storey office building with three different smartphones, it is proven that the two DWi-Fi approaches outperform the common models as static positioning yielded to position errors of about 5 m in average under good spatial conditions. Numéro de notice : A2017-791 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2017-0011 En ligne : https://doi.org/10.1515/jag-2017-0011 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89063 [article]

Application mobile et Web pour les observatoires photographiques du paysage / Jean-Baptiste Puel in Ingénierie des systèmes d'information, ISI : Revue des sciences et technologies de l'information, RSTI, vol 22 n° 5 (septembre - octobre 2017)

Public [article]  inIngénierie des systèmes d'information, ISI : Revue des sciences et technologies de l'information, RSTI > vol 22 n° 5 (septembre - octobre 2017) . - pp 59 - 68 Titre : Application mobile et Web pour les observatoires photographiques du paysage Type de document : Article/Communication Auteurs : Jean-Baptiste Puel, Auteur ; Bérengère Mathieu, Auteur ; Alain Crouzil, Auteur Année de publication : 2017 Article en page(s) : pp 59 - 68 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Formation [Termes IGN] appareil portable [Termes IGN] application web [Termes IGN] jeu sérieux [Termes IGN] paysage [Termes IGN] réalité augmentée [Termes IGN] téléphone intelligent Résumé : (auteur) Les travaux décrits dans cet article consistent en un ensemble d'outils développés dans le cadre des observatoires photographiques du paysage, dans le but d'en faciliter l'exploitation pédagogique. Nous présentons une application mobile permettant de reconduire les clichés d'un observatoire et d'en effectuer la segmentation en régions étiquetées ainsi qu'une application Web permettant d'accéder à tous les points de vue d'un observatoire et d'en suivre l'évolution grâce à des outils de comparaison. Enfin, nous mettons l'accent sur le potentiel pédagogique de ces outils et présentons différentes pistes d'utilisation dans l'enseignement secondaire. Numéro de notice : A2018-249 Affiliation des auteurs : non IGN Thématique : SOCIETE NUMERIQUE Nature : Article DOI : 10.3166/isi.22.5.59-68 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90309 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
093-2017051	SL	Revue	Centre de documentation	Revues en salle	Disponible

The differentiation of point symbols using selected visual variables in the mobile augmented reality system / Łukasz Halik in Cartographic journal (the), Vol 54 n° 2 (May 2017)  

Public [article]  inCartographic journal (the) > Vol 54 n° 2 (May 2017) . - pp 147 - 156 Titre : The differentiation of point symbols using selected visual variables in the mobile augmented reality system Type de document : Article/Communication Auteurs : Łukasz Halik, Auteur ; Beata Medyńska-Gulij, Auteur Année de publication : 2017 Article en page(s) : pp 147 - 156 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rédaction cartographique [Termes IGN] appareil portable [Termes IGN] figuré ponctuel [Termes IGN] navigation pédestre [Termes IGN] piéton [Termes IGN] Pologne [Termes IGN] réalité augmentée [Termes IGN] seuillage [Termes IGN] symbole graphique [Termes IGN] test de performance [Termes IGN] variable visuelle Résumé : (Auteur) On the basis of initial studies devoted to a better understanding of how the public user (a pedestrian in the city) perceives cartographic symbols in the mobile augmented reality system, we present an attempt to determine the threshold values of differentiation for three visual variables. The variables of size, transparency, and focus were implemented into image point symbols representing five types of objects. The set of symbols was designed in accordance with the rules of cartographic design taking into consideration an analysis of 19 professional tourist works. The symbols were presented on the screen of a mobile device in a system imitating the augmented reality system against four different backgrounds: white, a wall, and two typical urban landscapes. The results of an internet survey conducted using a tablet at four locations in Poznan (Poland) allowed us to determine the following: threshold differentiation values for the analysed variables, indication of the dependence on the type of background displayed on the mobile device in augmented reality, and the advantage of using a combination of visual variables. Numéro de notice : A2017-324 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2016.1253144 En ligne : http://dx.doi.org/10.1080/00087041.2016.1253144 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85397 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
030-2017021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Space-time multiple regression model for grid-based population estimation in urban areas / Ko Ko Lwin in International journal of geographical information science IJGIS, vol 30 n° 7- 8 (July - August 2016)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 30 n° 7- 8 (July - August 2016) . - pp 1579 - 1593 Titre : Space-time multiple regression model for grid-based population estimation in urban areas Type de document : Article/Communication Auteurs : Ko Ko Lwin, Auteur ; Komei Sugiura, Auteur ; Koji Zettsu, Auteur Année de publication : 2016 Article en page(s) : pp 1579 - 1593 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] appareil portable [Termes IGN] densité de population [Termes IGN] estimation statistique [Termes IGN] milieu urbain [Termes IGN] modèle conceptuel de données spatio-temporelles [Termes IGN] population [Termes IGN] régression multiple [Termes IGN] Twitter Résumé : (Auteur) We can collect, store, and analyze a huge amount of information about human mobility and social interaction activities due to the emergence of information and communication technologies and location-enabled mobile devices under cyber physical system frameworks. The high spatial resolution of population data on a multi-temporal scale is required by transport planners, human geographers, social scientists, and emergency management teams. In this study, we build a space-time multiple regression model to estimate grid-based (500 m × 500 m) spatial resolution at multi-temporal scale (30-min intervals) population data based on the space-time relationship among geospatially enabled person trip (PT) survey data and incorporate both mobile call (MC) and geotagged Twitter (GT) data. Since using geospatially enabled PT survey data as dependent variables enables us to acquire actual population amounts, which strongly depend on MCs and social interaction activities. Although many grids have a strong correlation between PT and MC/GT, some show fewer correlation results, especially where the grids have factories, schools, and workshops in which fewer MCs are found but a large population is presented. Although GT data are sparser than MCs, people from amusement and tourist areas can be detected by GT data. The space-time multiple regression model can also estimate the different amounts of populations based on human travel behavior that changes over space and time. According to accuracy assessments, the night-time estimated results, especially between 00:00 and 06:30, strongly correlate with national census data except in places where the grids have railway and subway stations. Numéro de notice : A2016-319 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2016.1143099 En ligne : http://dx.doi.org/10.1080/13658816.2016.1143099 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80939 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2016042	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2016041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Task selection in spatial crowdsourcing from worker’s perspective / Dingxiong Deng in Geoinformatica, vol 20 n° 3 (July - September 2016)  

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Towards fusing uncertain location data from heterogeneous sources / Bing Zhang in Geoinformatica, vol 20 n° 2 (April - June 2016)  

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Real-time depth-image-based rendering for viewpoint-variable display on mobile devices / Shuoran Yang (2016)  

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3-D Geovisualization of satellite images on smart devices by the integration of spatial DBMS, RESTful API and WebGL / Hyong-Woo Kim in Geocarto international, vol 30 n° 3 - 4 (March - April 2015)  

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The influence of digital surface model choice on visibility-based mobile geospatial applications / Sam Meek in Transactions in GIS, vol 17 n° 4 (August 2013)  

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Ephemeral conflation / Carlos-Humberto Gonzalez in Cartographic journal (the), vol 50 n° 1 (February 2013)  

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Spatial mashup technology and real time data integration in geo-web application using open source GIS: a case study for disaster management / Harish Chandra Karnatak in Geocarto international, vol 27 n° 6 (October 2012)  

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ThurGIS pour iPhone et Androïde / Office de la géoinformation du canton de thurgovie in Géomatique suisse, vol 110 n° 8 (01/08/2012) 

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Taking a walk along the bottom line / Anonyme in GEO: Geoconnexion international, vol 11 n° 5 (may 2012)

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Personal privacy jammers: Locating Jersey PPDs jamming GBAS [Ground-Based Augmentation System] safety-of-life signals / J. Grabowski in GPS world, vol 23 n° 4 (April 2012)

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