Descripteur
Documents disponibles dans cette catégorie (17)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
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
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 059-2010071 RAB Revue Centre de documentation En réserve L003 Disponible Potential accuracy of image orientation of small satellites: a case study of CHRIS/Proba data / Ahmed Shaker in Photogrammetric record, vol 23 n° 123 (September - November 2008)
[article]
Titre : Potential accuracy of image orientation of small satellites: a case study of CHRIS/Proba data Type de document : Article/Communication Auteurs : Ahmed Shaker, Auteur ; J. Nichol, Auteur ; M. Wong, Auteur Année de publication : 2008 Conférence : ISPRS 2007, High-Resolution Earth Imaging for Geospatial Information workshop 29/05/2007 01/06/2007 Hanovre Allemagne Article en page(s) : pp 275 - 289 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie spatiale
[Termes IGN] angle de visée
[Termes IGN] correction géométrique
[Termes IGN] espace image
[Termes IGN] espace objet
[Termes IGN] géoréférencement
[Termes IGN] Hong-Kong
[Termes IGN] image hyperspectrale
[Termes IGN] image PROBA-CHRIS
[Termes IGN] minisatellite
[Termes IGN] modèle empirique
[Termes IGN] modèle stéréoscopique
[Termes IGN] montagne
[Termes IGN] orientation d'image
[Termes IGN] point d'appui
[Termes IGN] précision géométrique (imagerie)Résumé : (Auteur) The new technology of small satellites (microsatellites) opens a new era in satellite observation of the earth. Small satellites such as ESA's Project for On-Board Autonomy (Proba), launched on 22nd October 2001, are of interest due to their low cost, flexibility of positioning, and capability for multiangular scanning in both across-track and along-track directions. Proba's Compact High Resolution Imaging Spectrometer (CHRIS) provides multidirectional, as well as hyperspectral, data at 18 m resolution and is supplied mainly to the scientific community for experimental environmental applications. This research evaluates the use of various empirical mathematical models for small satellite orientation and terrain modelling using the multidirectional viewing capabilities of CHRIS data. Geometric correction and co-registration of multiangle images is essential for their use for data extraction. Ideally, rigorous mathematical models should be formulated which precisely describe the satellite motion and represent the relationship between the image and the object spaces. The use of rigorous mathematical models has not been fully investigated using CHRIS/Proba data, because the satellite information provided is not adequate for rigorous sensor modelling. In this paper, several alternative empirical models are tested for the orientation and 3D geopositioning of CHRIS sensor images. The images used in this study cover extremely mountainous terrain in central Hong Kong. A set of five images from CHRIS/Proba taken in December 2005 from different angles are used to test the applicability of different forms of the empirical models for 3D geopositioning. The accuracy of the models is tested for different numbers and distribution of ground control points (GCPs) using different combinations of observation angles and base-to-height ratios. The results obtained show high integrity of the models used for CHRIS/Proba image orientation. In some cases, accuracy better than 2 pixels can be achieved using a modest number of GCPs. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2008-393 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2008.00490.x En ligne : https://doi.org/10.1111/j.1477-9730.2008.00490.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29386
in Photogrammetric record > vol 23 n° 123 (September - November 2008) . - pp 275 - 289[article]Réservation
Réserver ce documentExemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 106-08031 RAB Revue Centre de documentation En réserve L003 Disponible