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Wavelet modelling of the gravity field by domain decomposition methods: an example over Japan / Isabelle Panet in Geophysical journal international, vol 184 n° 1 (January 2011)
[article]
Titre : Wavelet modelling of the gravity field by domain decomposition methods: an example over Japan Type de document : Article/Communication Auteurs : Isabelle Panet , Auteur ; Yuki Kuroishi, Auteur ; Matthias Holschneider, Auteur Année de publication : 2011 Article en page(s) : pp 203 - 219 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse harmonique
[Termes IGN] bruit blanc
[Termes IGN] bruit rose
[Termes IGN] harmonique sphérique
[Termes IGN] itération
[Termes IGN] Japon
[Termes IGN] modèle de géopotentiel local
[Termes IGN] potentiel de pesanteur terrestre
[Termes IGN] transformation en ondelettesRésumé : (auteur) With the advent of satellite gravity, large gravity data sets of unprecedented quality at low and medium resolution become available. For local, high resolution field modelling, they need to be combined with the surface gravity data. Such models are then used for various applications, from the study of the Earth interior to the determination of oceanic currents. Here we show how to realize such a combination in a flexible way using spherical wavelets and applying a domain decomposition approach. This iterative method, based on the Schwarz algorithms, allows to split a large problem into smaller ones, and avoids the calculation of the entire normal system, which may be huge if high resolution is sought over wide areas. A subdomain is defined as the harmonic space spanned by a subset of the wavelet family. Based on the localization properties of the wavelets in space and frequency, we define hierarchical subdomains of wavelets at different scales. On each scale, blocks of subdomains are defined by using a tailored spatial splitting of the area. The data weighting and regularization are iteratively adjusted for the subdomains, which allows to handle heterogeneity in the data quality or the gravity variations. Different levels of approximations of the subdomains normals are also introduced, corresponding to building local averages of the data at different resolution levels. We first provide the theoretical background on domain decomposition methods. Then, we validate the method with synthetic data, considering two kinds of noise: white noise and coloured noise. We then apply the method to data over Japan, where we combine a satellite-based geopotential model, EIGEN-GL04S, and a local gravity model from a combination of land and marine gravity data and an altimetry-derived marine gravity model. A hybrid spherical harmonics/wavelet model of the geoid is obtained at about 15 km resolution and a corrector grid for the surface model is derived. Numéro de notice : A2011-604 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1365-246X.2010.04840.x Date de publication en ligne : 01/01/2011 En ligne : https://doi.org/10.1111/j.1365-246X.2010.04840.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91678
in Geophysical journal international > vol 184 n° 1 (January 2011) . - pp 203 - 219[article]Documents numériques
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Wavelet modelling of the gravity field .. - pdf éditeurAdobe Acrobat PDF The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise / R. Klees in Journal of geodesy, vol 84 n° 12 (December 2010)
[article]
Titre : The combination of GNSS-levelling data and gravimetric (quasi-) geoid heights in the presence of noise Type de document : Article/Communication Auteurs : R. Klees, Auteur ; I. Prutkin, Auteur Année de publication : 2010 Article en page(s) : pp 731 - 749 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] altitude normale
[Termes IGN] altitude orthométrique
[Termes IGN] bruit (théorie du signal)
[Termes IGN] champ de pesanteur local
[Termes IGN] collocation par moindres carrés
[Termes IGN] données GNSS
[Termes IGN] géoïde gravimétrique
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] matrice de covariance
[Termes IGN] nivellement par GPS
[Termes IGN] problème des valeurs limites
[Termes IGN] Suisse
[Termes IGN] varianceRésumé : (Auteur) We propose a methodology for the combination of a gravimetric (quasi-) geoid with GNSS-levelling data in the presence of noise with correlations and/or spatially varying noise variances. It comprises two steps: first, a gravimetric (quasi-) geoid is computed using the available gravity data, which, in a second step, is improved using ellipsoidal heights at benchmarks provided by GNSS once they have become available. The methodology is an alternative to the integrated processing of all available data using least-squares techniques or least-squares collocation. Unlike the corrector-surface approach, the pursued approach guarantees that the corrections applied to the gravimetric (quasi-) geoid are consistent with the gravity anomaly data set. The methodology is applied to a data set comprising 109 gravimetric quasi-geoid heights, ellipsoidal heights and normal heights at benchmarks in Switzerland. Each data set is complemented by a full noise covariance matrix. We show that when neglecting noise correlations and/or spatially varying noise variances, errors up to 10% of the differences between geometric and gravimetric quasi-geoid heights are introduced. This suggests that if high-quality ellipsoidal heights at benchmarks are available and are used to compute an improved (quasi-) geoid, noise covariance matrices referring to the same datum should be used in the data processing whenever they are available. We compare the methodology with the corrector-surface approach using various corrector surface models. We show that the commonly used corrector surfaces fail to model the more complicated spatial patterns of differences between geometric and gravimetric quasi-geoid heights present in the data set. More flexible parametric models such as radial basis function approximations or minimum-curvature harmonic splines perform better. We also compare the proposed method with generalized least-squares collocation, which comprises a deterministic trend model, a random signal component and a random correlated noise component. Trend model parameters and signal covariance function parameters are estimated iteratively from the data using non-linear least-squares techniques. We show that the performance of generalized least-squares collocation is better than the performance of corrector surfaces, but the differences with respect to the proposed method are still significant. Numéro de notice : A2010-559 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0406-2 Date de publication en ligne : 29/08/2010 En ligne : https://doi.org/10.1007/s00190-010-0406-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30751
in Journal of geodesy > vol 84 n° 12 (December 2010) . - pp 731 - 749[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-02010121 SL Revue Centre de documentation Revues en salle Disponible 266-2010121 SL Revue Centre de documentation Revues en salle Disponible Noise-signal index threshold: a new noise-reduction technique for generation of reference spectra and efficient hyperspectral image classification / K. Kusuma in Geocarto international, vol 25 n° 7 (November 2010)
[article]
Titre : Noise-signal index threshold: a new noise-reduction technique for generation of reference spectra and efficient hyperspectral image classification Type de document : Article/Communication Auteurs : K. Kusuma, Auteur ; D. Ramakrishnan, Auteur ; H. Pandalai, Auteur ; G. Kailash, Auteur Année de publication : 2010 Article en page(s) : pp 569 - 580 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] bruit blanc
[Termes IGN] classification spectrale
[Termes IGN] correction radiométrique
[Termes IGN] filtrage du bruit
[Termes IGN] modèle empirique
[Termes IGN] réponse spectrale
[Termes IGN] seuillage d'imageRésumé : (Auteur) Reference spectra of terrestrial targets are usually collected using field spectro-radiometers for mineral abundance mapping and target detection. These spectra often have noise that masks characteristic absorption and reflection features and affects the efficiency of material mapping. This work aims at obtaining an empirical technique for reduction of high-frequency noise from field spectra. The proposed noise correction technique uses a 'normalized' measure Rn, where Rn = (Ln - Fn)/Ln for each band (n) calculated from field and laboratory spectra of test material, with Fn and Ln being the depth of the absorption feature in field and laboratory spectra, respectively. On the basis of the assumption of the constancy of this ratio in neighbouring bands, an empirical algorithm that approximates the ratio Rn of a noisy band to the corrected ratio of an adjacent band is used to obtain the noise-corrected field spectra. The classification accuracy increases significantly when noise reduced field spectra are used as reference spectra. Numéro de notice : A2010-471 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2010.510582 Date de publication en ligne : 16/09/2010 En ligne : https://doi.org/10.1080/10106049.2010.510582 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30664
in Geocarto international > vol 25 n° 7 (November 2010) . - pp 569 - 580[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-2010071 RAB Revue Centre de documentation En réserve L003 Disponible Alternative methodologies for the internal quality control of parallele LIDAR strips / A. Habib in IEEE Transactions on geoscience and remote sensing, vol 48 n° 1 Tome 1 (January 2010)
[article]
Titre : Alternative methodologies for the internal quality control of parallele LIDAR strips Type de document : Article/Communication Auteurs : A. Habib, Auteur ; A.P. Kesrting, Auteur ; K.I. Bang, Auteur ; D.C. Lee, Auteur Année de publication : 2010 Article en page(s) : pp 221 - 236 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] bruit (théorie du signal)
[Termes IGN] contrôle qualité
[Termes IGN] données lidar
[Termes IGN] erreur systématique
[Termes IGN] lasergrammétrie
[Termes IGN] procédé
[Termes IGN] recouvrement d'images
[Termes IGN] semis de pointsRésumé : (Auteur) Light Detection and Ranging (LiDAR) systems have been widely adopted for the acquisition of dense and accurate topographic data over extended areas. Although the utilization of this technology has increased in different applications, the development of standard methodologies for the quality control (QC) of LiDAR data has not followed the same trend. In other words, a lack in reliable, practical, cost-effective, and commonly acceptable QC procedures is evident. A frequently adopted procedure for QC is comparing the LiDAR data to ground control points. Aside from being expensive, this approach is not accurate enough for the verification of horizontal accuracy, unless specifically designed LiDAR targets are used. This paper is dedicated to providing accurate, economical, and convenient internal QC procedures for the evaluation of LiDAR data, which is captured from parallel flight lines. The underlying concept of the proposed methodologies is that, in the absence of systematic and random errors in system parameters and measurements, conjugate surface elements in overlapping strips should perfectly match each other. Consistent incompatibilities and the quality of fit between conjugate surface elements in overlapping strips can be used to detect systematic errors in the system parameters/measurements and to evaluate the noise level in the LiDAR point cloud, respectively. Experimental results from real data demonstrate that all the proposed methods, with one exception, produce compatible estimates of systematic discrepancies between the involved data sets, as well as good quantification of inherent noise. Copyright IEEE Numéro de notice : A2010-020 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2009.2026424 Date de publication en ligne : 15/09/2009 En ligne : https://doi.org/10.1109/TGRS.2009.2026424 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30216
in IEEE Transactions on geoscience and remote sensing > vol 48 n° 1 Tome 1 (January 2010) . - pp 221 - 236[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2010011A RAB Revue Centre de documentation En réserve L003 Disponible
contenu dans Photogrammetric computer vision and image analysis, ISPRS Commission 3 symposium, Saint-Mandé, 1-3 septembre 2010, volume 1. Papers accepted on the basis of peer-reviewed full manuscripts / Nicolas Paparoditis (2010)
Titre : Panorama-based camera calibration Type de document : Article/Communication Auteurs : Bertrand Cannelle , Auteur ; Nicolas Paparoditis , Auteur ; Olivier Tournaire , Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2010 Conférence : PCV 2010, ISPRS - Commission 3 symposium Photogrammetric computer vision and image analysis 01/09/2010 03/09/2010 Saint-Mandé France ISPRS OA Archives Importance : pp 73 - 78 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] bruit (théorie du signal)
[Termes IGN] chambre panoramique
[Termes IGN] étalonnage de capteur (imagerie)Résumé : (Auteur) This paper presents a method to calibrate a camera from panoramas. Camera calibration using panoramas has two main advantages: on the one hand it requires neither ground control points or calibration patterns and on the other hand the estimation of intrinsic and distortion parameters is of higher quality due to the loop constraint and to a decorrelation of tied parameters due to the fixed perspective center.
The paper is organised as follow. The first part presents the acquisition process and our mathematical estimation framework. The second part explores with simulated data sets the impact of noisy measures, of geometry of acquisition and of unmodelled parallaxes on the calibration results. A comparison with a traditional calibration method (i.e by using a 3D target network) is then studied. The final section presents results in a real case and compares the results obtained with our panorama approach against the classical calibration. The results are very promising.Numéro de notice : C2010-001 Affiliation des auteurs : MATIS (1993-2011) Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.isprs.org/proceedings/XXXVIII/part3/a/pdf/73_XXXVIII-part3A.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65056 Wavelet modeling of the gravity field over Japan / Isabelle Panet in Bulletin of the Geographical survey institute, vol 57 (December 2009)PermalinkComparative geometric and radiometric evaluation of mobile phone and still video cameras / Devrim Akca in Photogrammetric record, vol 24 n° 127 (September - November 2009)PermalinkCombs filtering: improving acquisition and tracking in GNSS receivers / A. Dempster in GPS world, vol 20 n° 3 (March 2009)PermalinkUsing ENVISAT ASAR global mode data for surface soil moisture retrieval over Oklahoma, USA / Carsten Pathe in IEEE Transactions on geoscience and remote sensing, vol 47 n° 2 (February 2009)PermalinkConsideration of time-correlated errors in a Kalman filter applicable to GNSS / M.G. Potovello in Journal of geodesy, vol 83 n° 1 (January 2009)PermalinkPrecise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis / Rodrigo Figueiredo Leandro (2009)PermalinkSources d'erreurs et combinaisons linéaires des trois fréquences du système Galiléo pour le positionnement différentiel / L. Tabti in Bulletin des sciences géographiques, n° 22 (octobre 2008)PermalinkFast error analysis of continuous GPS observations / M. Bos in Journal of geodesy, vol 82 n° 3 (March 2008)PermalinkReflecting on GPS: sensing land and ice from low Earth orbit / S.T. Gleason in GPS world, vol 18 n° 10 (October 2008)PermalinkOn the long-term stability of microwave radiometers using noise diodes for calibration / S.T. Brown in IEEE Transactions on geoscience and remote sensing, vol 45 n° 7 Tome 1 (July 2007)Permalink