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Retrieval of phase history parameters from distributed scatterers in urban areas using very high resolution SAR data / Y. Wang in ISPRS Journal of photogrammetry and remote sensing, vol 73 (September 2012)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 73 (September 2012) . - pp 89 - 99 Titre : Retrieval of phase history parameters from distributed scatterers in urban areas using very high resolution SAR data Type de document : Article/Communication Auteurs : Y. Wang, Auteur ; X. Zhu, Auteur ; R. Balmer, Auteur Année de publication : 2012 Article en page(s) : pp 89 - 99 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] coin réflecteur [Termes IGN] image radar moirée [Termes IGN] image TerraSAR-X [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] matrice de covariance [Termes IGN] milieu urbain [Termes IGN] phase [Termes IGN] rapport signal sur bruit [Termes IGN] reconstruction du signal Résumé : (Auteur) In a recent contribution Ferretti and co-workers (Ferretti, A., Fumagalli, A., Novali, F., Prati, C., Rocca, F., Rucci, A., 2011. A new algorithm for processing interferometric data-stacks: SqueeSAR IEEE Transactions on Geoscience and Remote Sensing 49(9), pp. 3460–3470) have proposed the SqueeSAR method, a way to exploit temporally coherent distributed scatterers in coherent SAR data stacks. Elevation and deformation or subsidence estimates are obtained with accuracy similar as in the well known persistent scatterer interferometry (PSI). In this paper, we propose an alternative approach and provide a first demonstration of the optimal estimation of distributed scatterers’ phase histories in urban areas. Different to SqueeSAR, we derive phase histories for each distributed scatterer pixel rather than for groups of pixels. We use the Anderson–Darling statistical test to identify neighboring samples of the same distribution. Prior to covariance matrix estimation required for maximum likelihood estimation we apply a multi-resolution defringe technique. By using TerraSAR-X high resolution spotlight data, it is demonstrated that we are able to retrieve reliable phase histories and motion parameter estimates from distributed scatterers with signal-to-noise-ratio far below the common range. Numéro de notice : A2012-547 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : /10.1016/j.isprsjprs.2012.06.007 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.06.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31993 [article]

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Consistency of accuracy assessment indices for soft classification: simulation analysis / J. Chen in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 2 (March - April 2010)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 2 (March - April 2010) . - pp 156 - 164 Titre : Consistency of accuracy assessment indices for soft classification: simulation analysis Type de document : Article/Communication Auteurs : J. Chen, Auteur ; X. Zhu, Auteur ; H. Imura, Auteur ; X. Chen, Auteur Année de publication : 2010 Article en page(s) : pp 156 - 164 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] classification [Termes IGN] erreur moyenne quadratique [Termes IGN] estimation de précision [Termes IGN] Kappa de Cohen [Termes IGN] matrice de confusion [Termes IGN] niveau d'analyse [Termes IGN] précision cartographique [Termes IGN] précision décimétrique [Termes IGN] simulation Résumé : (Auteur) Accuracy assessment plays a crucial role in the implementation of soft classification. Even though many indices of accuracy assessment for soft classification have been proposed, the consistencies among these indices are not clear, and the impact of sample size on these consistencies has not been investigated. This paper examines two kinds of indices: map-level indices, including root mean square error (rmse), kappa, and overall accuracy (oa) from the sub-pixel confusion matrix (SCM); and category-level indices, including crmse, user accuracy (ua) and producer accuracy (pa). A careful simulation was conducted to investigate the consistency of these indices and the effect of sample size. The major findings were as follows: (1) The map-level indices are highly consistent with each other, whereas the category-level indices are not. (2) The consistency among map-level and category-level indices becomes weaker when the sample size decreases. (3) The rmse is more affected by error distribution among classes than are kappa and oa. Based on these results, we recommend that rmse can be used for map-level accuracy due to its simplicity, although kappa and oa may be better alternatives when the sample size is limited because the two indices are affected less by the error distribution among classes. We also suggest that crmse should be provided when map users are not concerned about the error source, whereas ua and pa are more useful when the complete information about different errors is required. The results of this study will be of benefit to the development and application of soft classifiers. Copyright ISPRS Numéro de notice : A2010-090 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2009.10.003 En ligne : https://doi.org/10.1016/j.isprsjprs.2009.10.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30286 [article]

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Developing Web-based mapping applications through distributed object technology / X. Zhu in Cartography and Geographic Information Science, vol 28 n° 4 (October 2001)  

Public [article]  inCartography and Geographic Information Science > vol 28 n° 4 (October 2001) . - pp 249 - 258 Titre : Developing Web-based mapping applications through distributed object technology Type de document : Article/Communication Auteurs : X. Zhu, Auteur Année de publication : 2001 Article en page(s) : pp 249 - 258 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] base de données répartie [Termes IGN] carte interactive [Termes IGN] cartographie par internet [Termes IGN] CORBA [Termes IGN] toile d'araignée mondiale Résumé : (Auteur) Emerging webbased mapping technologies use the World Wide Web (WWW) and Internet protocols to provide the ability to distribute, access, and visualize geospatial information over the Internet. Many webbased mapping applications have been developed to deliver geospatial information within and across organizations and even to the public at large. A major technological challenge is to achieve interoperability amongst webbased mapping applications so that mapping and geoprocessing resources distributed over the Internet can be shared and integrated. This paper presents an approach to the development of webbased mapping applications using distributed object technology in order to enable interoperability. Distributed object technology combines object technology, which utilizes reusable software components (called objects) that model realworld entities to build software systems, and distributed computing, which allows computing resources to be distributed and accessed over computer networks. The paper introduces a distributed object technology, the Common Object Request Broker Architecture (CORBA); proposes an architecture for webbased mapping using CORBA ; and presents a prototype implementation. Numéro de notice : A2001-162 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304001782152973 En ligne : https://doi.org/10.1559/152304001782152973 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21857 [article]

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