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A geometry and texture coupled flexible generalization of urban building models / M. Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 70 (June 2012)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 70 (June 2012) . - pp 1 - 24 Titre : A geometry and texture coupled flexible generalization of urban building models Type de document : Article/Communication Auteurs : M. Zhang, Auteur ; L. Zhang, Auteur ; P. Takis, Auteur ; P. Takis Mathiopoulos, Auteur ; W. Xie, Auteur ; Y. Ding, Auteur ; H. Wang, Auteur Année de publication : 2012 Article en page(s) : pp 1 - 24 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] attribut géomètrique [Termes IGN] CityGML [Termes IGN] données localisées 3D [Termes IGN] façade [Termes IGN] généralisation du bâti [Termes IGN] instance [Termes IGN] modèle 3D de l'espace urbain [Termes IGN] modèle numérique du bâti [Termes IGN] précision géométrique (imagerie) [Termes IGN] réalité virtuelle [Termes IGN] reconstruction 3D du bâti [Termes IGN] texture d'image [Vedettes matières IGN] Généralisation Résumé : (Auteur) In the past, numerous research efforts have focused on generalization of city building models. However, a generic procedure for creating flexible generalization results supporting the fast and efficient update of original building models with various complexities is still an open problem. Moreover, building clusters created in previously published generalization methods are not flexible enough to meet the various requirements for both legible and realistic visualization. Motivated by these observations, this paper proposes a new method for generating a flexible generalization outcome which enables convenient updating of original building models. It also proposes a flexible preprocessing of this generalized information to render a legible and realistic urban scene. This is accomplished by introducing a novel component structure, termed as FEdge, particularly designed for efficiently managing the geometry and texture information in building cluster instances (both original building models and building clusters) during the generalization, visualization and updating processes. Furthermore, a multiple representation structure, referred to as Evolved Buffer-Tree (EBT), is also introduced. The purpose of the EBT is to organize building cluster instances and to employ more flexible LODs for both legible and realistic visualization of urban scenes. FEdge has an intuitive planar shape which can be effectively used in representing rough 3D facade composed by detailed continuous meshes. Each FEdge is given a unique identifier, referred to as FEdge Index. In the proposed generalization scheme, firstly each original building model treated as a building cluster instance is abstracted and presented as FEdge Indices. These FEdge Indices are then used for producing generalized building cluster instances in the EBT portably, and to support convenient model updating and flexible preprocessing of the generalization results for renderable building cluster instances. Secondly, to achieve a legible and realistic visualization of urban scene, the EBT is flexibly assigned diverse LODs maintaining more important legible information than LODs defined in CityGML for 3D building models. To make the generalization more accurate by considering the city roads and districts, an algorithm for automatic road analysis is applied in our clustering and combination. Numerous experiments considering the geometrical and textural complexity of common urban building models, as well as a typical case study of complex city scene with a large number of building models, verify the effectiveness of our generalization method and the dynamic visualization of the generalized urban models. Numéro de notice : A2012-285 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2012.03.008 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.03.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31731 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2012041	SL	Revue	Centre de documentation	Revues en salle	Disponible

Applications of ICA for the enhancement and classification of polarimetric SAR images / H. Wang in International Journal of Remote Sensing IJRS, vol 29 n° 6 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 6 (March 2008) . - pp 1649 - 1663 Titre : Applications of ICA for the enhancement and classification of polarimetric SAR images Type de document : Article/Communication Auteurs : H. Wang, Auteur ; Y. Pi, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 1649 - 1663 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse en composantes indépendantes [Termes IGN] couleur à l'écran [Termes IGN] données polarimétriques [Termes IGN] filtre de déchatoiement [Termes IGN] image en couleur composée [Termes IGN] image radar moirée [Termes IGN] image RVB Résumé : (Auteur) Independent components analysis (ICA) based methods for polarimetric synthetic aperture radar (SAR) image speckle reduction and ground object classification are studied. Several independent components can be extracted from polarimetric SAR images using ICA directly. The component with lowest speckle index is regarded as the scene after speckle reduction. The disadvantage of this method is that only one image is kept and most polarization information will be lost. In this paper, we use ICA-sparse-coding shrinkage (ICA-SPS) based speckle reduction method, which is implemented on each individual image and can keep polarization information. It is carried out on the combined channels obtained by Pauli-decomposition rather than original polarization channels in order to keep relative phase information among polarization channels and get better performance. After ICA-SPS, the effect of speckle suppression on SAR image classification can be compared favourably with other methods by combining the channels into a false colour image. At last, a new ICA-based classification method is presented. In this method, four independent components are separated by ICA from five polarization and combined channels. One of these independent components which includes little ground object information is regarded as speckle noise and therefore be discarded. The remaining three components can be treated as subordination coefficients of three kinds of targets. A classified image can be obtained based on the components. And by composing these three channels in RGB colour pattern, a false colour image can be constructed. Numéro de notice : A2008-085 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701395211 En ligne : https://doi.org/10.1080/01431160701395211 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29080 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-08041	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Image misregistration error in change measurements / H. Wang in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 9 (September 2005)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 71 n° 9 (September 2005) . - pp 1037 - 1044 Titre : Image misregistration error in change measurements Type de document : Article/Communication Auteurs : H. Wang, Auteur ; E.C. Ellis, Auteur Année de publication : 2005 Article en page(s) : pp 1037 - 1044 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse comparative [Termes IGN] cartographie écologique [Termes IGN] Chine [Termes IGN] détection de changement [Termes IGN] erreur de positionnement [Termes IGN] Etats-Unis [Termes IGN] image à résolution métrique [Termes IGN] image Ikonos [Termes IGN] orthophotographie [Termes IGN] paysage rural [Termes IGN] paysage urbain [Termes IGN] planimétrie [Termes IGN] précision de localisation [Termes IGN] réalité de terrain [Termes IGN] régression Résumé : (Auteur) Planimetric positional error limits the accuracy of landscape change measurements based on features interpreted from high spatial resolution imagery ( Numéro de notice : A2005-389 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.71.9.1037 En ligne : https://doi.org/10.14358/PERS.71.9.1037 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27525 [article]

Spatial accuracy of orthorectified Ikonos imagery and historical aerial photographs across five sites in China / H. Wang in International Journal of Remote Sensing IJRS, vol 26 n° 9 (May 2005)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 26 n° 9 (May 2005) . - pp 1893 - 1911 Titre : Spatial accuracy of orthorectified Ikonos imagery and historical aerial photographs across five sites in China Type de document : Article/Communication Auteurs : H. Wang, Auteur ; E.C. Ellis, Auteur Année de publication : 2005 Article en page(s) : pp 1893 - 1911 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse diachronique [Termes IGN] analyse spatio-temporelle [Termes IGN] Chine [Termes IGN] détection de changement [Termes IGN] image à résolution métrique [Termes IGN] image Ikonos [Termes IGN] modèle par fonctions rationnelles [Termes IGN] photographie aérienne [Termes IGN] point d'appui [Termes IGN] précision géométrique (imagerie) Résumé : (Auteur) High-resolution ( 1m) satellite imagery and archival World War 2 era (WW2) aerial photographs are currently available to support high-resolution longterm change measurements at sites across China. A major limitation to these measurements is the spatial accuracy with which this imagery can be orthorectified and co-registered. We orthorectified IKONOS 1m resolution GEO-format imagery and WW2 aerial photographs across five 100km2 rural sites in China with terrain ranging from flat to hilly to mountainous. Ground control points (GCPs) were collected uniformly across 100 km2 IKONOS scenes using a differential Global Positioning Systems (GPS) field campaign. WW2 aerial photos were co-registered to orthorectified IKONOS imagery using bundle block adjustment and rational function models. GCP precision, terrain relief and the number and distribution of GCPs significantly influenced image orthorectification accuracy. Root mean square errors (RMSEs) at GCPs for IKONOS imagery were Numéro de notice : A2005-256 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160512331326684 En ligne : https://doi.org/10.1080/01431160512331326684 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27392 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-05091	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt