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Simultaneous denoising and intrinsic order selection in hyperspectral imaging / M. Farzam in IEEE Transactions on geoscience and remote sensing, vol 49 n° 9 (September 2011)
[article]
Titre : Simultaneous denoising and intrinsic order selection in hyperspectral imaging Type de document : Article/Communication Auteurs : M. Farzam, Auteur ; S. Beheshti, Auteur Année de publication : 2011 Article en page(s) : pp 3423 - 3436 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] bruit atmosphérique
[Termes IGN] classification automatique
[Termes IGN] estimation de précision
[Termes IGN] filtrage du bruit
[Termes IGN] image hyperspectrale
[Termes IGN] propagation d'erreur
[Termes IGN] rapport signal sur bruitRésumé : (Auteur) In this paper, we address the problem of order selection in noisy hyperspectral applications. In conventional unmixing methods, this problem has been divided into two separate processes of order selection and unmixing. Order selection methods generally use a denoising approach at the beginning stage. The data in this case pass through three stages: denoising, order selection, and unmixing. Each of these steps mainly aims to optimize a different criterion independently. In addition, any error created in the denoising process will be propagated not only to the order selection stage but also consequently to the unmixing results. Commonly used denoising methods such as eigenvalue-decomposition-based methods, e.g., singular-value-decomposition-based methods, provide a threshold value to separate the noise from the signal. These approaches are heavily sensitive to the threshold value and signal-to-noise ratio (SNR). Moreover, these methods tend to lose their efficiency rapidly for lower SNRs. Note that both the denoising step and the dimension estimation step aim to provide the optimum estimate of the same noiseless data. Consequently, adopting a simultaneous denoising and dimension estimation method with a goal to provide the optimum estimate of the desired noiseless data is rational. This process not only avoids possible error propagations from the denoising stage to the dimension estimation stage but also unifies the optimization criteria that were used in each of these steps. In this paper, a simultaneous denoising and dimension estimation method is introduced. The approach is based on minimizing the estimated mean square error. Minimization is done by comparing the estimated data in a range of subspaces dictated by a simultaneous process. Minimizing the error at once, the proposed method denoises the data and provides the optimum dimension simultaneously. Owing to the parallel processing of denoising and dimension estimation, the simulation results show the advantages of the proposed method over some of the state-of-the-art approaches and illustrate a substantial performance, particularly for cases with a lower SNR. Numéro de notice : A2011-363 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2119400 Date de publication en ligne : 29/04/2011 En ligne : https://doi.org/10.1109/TGRS.2011.2119400 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31142
in IEEE Transactions on geoscience and remote sensing > vol 49 n° 9 (September 2011) . - pp 3423 - 3436[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2011091 RAB Revue Centre de documentation En réserve L003 Disponible Statistical analysis of signal measurement in time-of-flight cameras / F. Mufti in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 5 (September - October 2011)
[article]
Titre : Statistical analysis of signal measurement in time-of-flight cameras Type de document : Article/Communication Auteurs : F. Mufti, Auteur Année de publication : 2011 Article en page(s) : pp 720 - 731 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] acquisition d'images
[Termes IGN] bruit (théorie du signal)
[Termes IGN] caméra numérique
[Termes IGN] image 3D
[Termes IGN] intensité lumineuse
[Termes IGN] phase
[Termes IGN] photographie terrestre
[Termes IGN] rapport signal sur bruit
[Termes IGN] temps de vol
[Termes IGN] traitement du signalRésumé : (Auteur) Three-dimensional imaging systems have evolved significantly in the last two decades due to increase in demand for tasks in the field of close range photogrammetry. The fast and growing need of 3D imaging devices has given rise to range image technology, especially time-of-flight (TOF) cameras, that provide direct measurement of distance between the camera and the targeted surface. A significant advantage of TOF devices over traditional range data sensors is their capability to provide frame rate range data over a full image array. In phase shift TOF cameras, phase shift sampling of the received signal is used to measure amplitude, phase and the offset (intensity) of the received signal. As a result, the quality of the measurement of these sensors depends heavily on signal-to-noise (SNR) of the incoming signal and the subsequent processing algorithms. A detailed understanding of the statistical distributions of the measurement parameters is crucial for accurate distance measurement analysis especially in low SNR scenarios. In this paper, we provide explicit noise models for the three parameters of amplitude, phase and intensity. The proposed stochastic model helps in investigating the effect of noise on signal and classifying range data reliability in TOF cameras. The model is used for prediction of errors in a TOF camera under various SNR conditions. Experimental verification confirms the validity of the model using real data for range error classification under different noise conditions. Numéro de notice : A2011-407 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2011.06.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2011.06.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31186
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 5 (September - October 2011) . - pp 720 - 731[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2011051 SL Revue Centre de documentation Revues en salle Disponible Physical limitations on detecting tunnels using underground-focusing spotlight synthetic aperture radar / J. Martinez-Lorenzo in IEEE Transactions on geoscience and remote sensing, vol 49 n° 1 Tome 1 (January 2011)
[article]
Titre : Physical limitations on detecting tunnels using underground-focusing spotlight synthetic aperture radar Type de document : Article/Communication Auteurs : J. Martinez-Lorenzo, Auteur ; C. Rappaport, Auteur ; F. Quivira, Auteur Année de publication : 2011 Conférence : IGARSS 2009, International Geoscience And Remote Sensing Symposium 12/07/2009 17/07/2009 Le Cap Afrique du sud Proceedings IEEE Article en page(s) : pp 65 - 70 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] constante diélectrique
[Termes IGN] détection de partie cachée
[Termes IGN] écho radar
[Termes IGN] forme d'onde
[Termes IGN] image radar moirée
[Termes IGN] propagation du signal
[Termes IGN] réflectance du sol
[Termes IGN] réfraction atmosphérique
[Termes IGN] rugosité du sol
[Termes IGN] sable
[Termes IGN] tunnelRésumé : (Auteur) This paper examines the feasibility of underground-focusing spotlight synthetic aperture radar (UF-SL-SAR) systems for tunnel detection applications. A general formulation is reviewed for generating UF-SL-SAR imaging by using multiple frequencies across a wide band and by focusing in space to subsurface points using well-known ray refraction at the nominal ground surface. A full-wave finite-difference frequency-domain model is used to consider wave propagation in realistic soil with loss- and frequency-dependent dielectric constant and a randomly rough ground surface, both of which serve to obscure and distort the returned tunnel target signal. Imaging results are presented for two representative soil scenarios: dry sand and moist clay loam. Considering the ground surface ray refraction for focusing greatly improves the SAR image relative to conventional SAR focusing at the ground surface. Using UF-SL-SAR, a small shallow tunnel is reasonably imaged for the sand case, despite the roughness of the ground interface. However, for higher conductivity moist clay loam, the clutter from the rough surface overwhelms the significantly attenuated target signal, which must propagate through the lossy intervening soil. It is demonstrated that, despite ideal focusing, the tunnel is successfully imaged only for the sand case. Numéro de notice : A2011-048 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2010.2051952 Date de publication en ligne : 19/08/2010 En ligne : https://doi.org/10.1109/TGRS.2010.2051952 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30829
in IEEE Transactions on geoscience and remote sensing > vol 49 n° 1 Tome 1 (January 2011) . - pp 65 - 70[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2011011A RAB Revue Centre de documentation En réserve L003 Disponible GNSS RF Compatibility assessment: Interference among GPS, Galileo and Compass / W. Liu in GPS world, vol 21 n° 12 (December 2010)
[article]
Titre : GNSS RF Compatibility assessment: Interference among GPS, Galileo and Compass Type de document : Article/Communication Auteurs : W. Liu, Auteur ; X. Zhan, Auteur ; L. Liu, Auteur ; M. Niu, Auteur Année de publication : 2010 Article en page(s) : pp 32 - 40 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] compatibilité
[Termes IGN] configuration (matériel informatique)
[Termes IGN] dégradation du signal
[Termes IGN] géonavigateur
[Termes IGN] interférence
[Termes IGN] rapport signal sur bruit
[Termes IGN] récepteur GNSS
[Termes IGN] récepteur mixte
[Termes IGN] signal BeiDou
[Termes IGN] signal Galileo
[Termes IGN] signal GNSS
[Termes IGN] signal GPSRésumé : (Auteur) A comprehensive methodology combines spectral-separation and code-tracking spectral-sensitivity coefficients to analyze interference among GPS, Galileo, and Compass. The authors propose determining the minimum acceptable degradation of effective carrier-to-noise-density ratio, considering all receiver processing phases, and conclude that each GNSS can provide a sound basis for compatibility with other GNSS with respect to the special receiver configuration. Numéro de notice : A2010-540 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30732
in GPS world > vol 21 n° 12 (December 2010) . - pp 32 - 40[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-2010121 RAB Revue Centre de documentation En réserve L003 Disponible Level Crossing Rate Estimation (LCRE): a new technique for finding GNSS carrier-to-noise ratios / Elena Simona Lohan in Inside GNSS, vol 5 n° 6 (September 2010)
[article]
Titre : Level Crossing Rate Estimation (LCRE): a new technique for finding GNSS carrier-to-noise ratios Type de document : Article/Communication Auteurs : Elena Simona Lohan, Auteur ; D. Skournetou, Auteur Année de publication : 2010 Article en page(s) : 10 p. ; pp 36 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] phase GNSS
[Termes IGN] rapport signal sur bruit
[Termes IGN] récepteur GNSSRésumé : (Auteur) The authors propose a new carrier-to-noise ratio (CNR) estimation method - an important metric in GNSS receiver operation - based on use of the level crossing rate of a receiver’s correlation function. Numéro de notice : A2010-673 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33455
in Inside GNSS > vol 5 n° 6 (September 2010) . - 10 p. ; pp 36 - 47[article]Documents numériques
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