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Full-wave calibration of time- and frequency-domain ground-penetrating radar in far-field conditions / Mohammad Reza Mahmoudzadeh Ardekani in IEEE Transactions on geoscience and remote sensing, vol 52 n° 1 tome 2 (January 2014)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 52 n° 1 tome 2 (January 2014) . - pp 664 - 678 Titre : Full-wave calibration of time- and frequency-domain ground-penetrating radar in far-field conditions Type de document : Article/Communication Auteurs : Mohammad Reza Mahmoudzadeh Ardekani, Auteur ; Sébastien Lambot, Auteur Année de publication : 2014 Article en page(s) : pp 664 - 678 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] étalonnage d'instrument [Termes IGN] forme d'onde pleine [Termes IGN] fréquence [Termes IGN] image radar [Termes IGN] radar pénétrant GPR [Termes IGN] temps Résumé : (Auteur) Full-wave modeling of ground-penetrating radar (GPR) data using Green's functions for wave propagation in planar layered media and antenna characteristic global reflection and transmission functions for describing far-field antenna effects, including antenna-medium interactions, has shown a great potential for nondestructive characterization of soils and materials. The accuracy of the retrieved parameters in the GPR data inversion depends on the accuracy of the GPR external calibration. In this research, we studied the stability and the repeatability of two different GPR systems, namely, frequency- and time-domain systems. A combination of a vector network analyzer and 800-5200 MHz horn antenna was used as a frequency-domain GPR (FD-GPR) whereas a GSSI GPR system using a 900 MHz bowtie antenna was used as a time-domain GPR (TD-GPR). Both GPR systems including their antennas were calibrated several times using measurements with the antennas at different heights over a perfect electric conductor (PEC) in the laboratory as well as over a water layer. In addition, measurements were performed over a thin water layer and a relatively thick sandy soil layer as validating medium. The results showed that the FD-GPR is relatively stable while the TD-GPR presents a significant drift which can be accounted for using corrections based on the air direct-coupling waves (free-space measurements). Water- and PEC-based calibrations provided very similar results for the GPR calibration functions. Inversions for the water layer and the sandy soil layer provided reliable results and showed a high degree of the repeatability for both radar systems. The error on the calibration based on inaccurate antenna heights over PEC showed the significant errors on the inversion results for the directive antenna (horn antenna) but less error for the bowtie antenna. This analysis demonstrated the general validity of the proposed far-field radar modeling approach, not only with respect to frequency and time domain radars but as well with respect to the calibrating medium. Numéro de notice : A2014-039 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2243458 En ligne : https://doi.org/10.1109/TGRS.2013.2243458 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32944 [article]

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065-2014011B	RAB	Revue	Centre de documentation	En réserve L003	Disponible

LiDAR-derived surface roughness texture mapping: Application to mount St. Helens Pumice Plain deposit analysis / Patrick L. Whelley in IEEE Transactions on geoscience and remote sensing, vol 52 n° 1 tome 2 (January 2014)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 52 n° 1 tome 2 (January 2014) . - pp 426 - 438 Titre : LiDAR-derived surface roughness texture mapping: Application to mount St. Helens Pumice Plain deposit analysis Type de document : Article/Communication Auteurs : Patrick L. Whelley, Auteur Année de publication : 2014 Article en page(s) : pp 426 - 438 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] alluvion [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] montagne [Termes IGN] plaine [Termes IGN] rugosité du sol [Termes IGN] Saint-Helens, Mont [Termes IGN] semis de points [Termes IGN] texture d'image [Termes IGN] volcan Résumé : (Auteur) Statistical measures of patterns (textures) in surface roughness are used to quantitatively differentiate volcanic deposit facies on the Pumice Plain, on the northern flank of Mount St. Helens (MSH). Surface roughness values are derived from a Light Detection and Ranging (LiDAR) point cloud collected in 2004 from a fixed-wing airborne platform. Patterns in surface roughness are characterized using co-occurrence texture statistics. Pristine-pyroclastic, reworked-pyroclastic, mudflow, boulder beds, eroded lava flows, braided streams, and other units within the Pumice Plain are all found to have significantly distinct roughness textures. The MSH deposits are reasonably accessible, and the textural variations have been verified in the field. Results of this work indicate that by affecting the distribution of large clasts and tens-of-meter scale landforms, modification of pyroclastic deposits by lahars alters the morphology of the surface in detectable quantifiable ways. When a lahar erodes a pyroclastic deposit, surface roughness increases, as does the randomness in the deposit surface. Conversely, when a lahar deposits material, the resulting landforms are less rough but more random than pristine pumice-rich pyroclastic deposits. By mapping these relationships and others, volcanic deposit facies can be differentiated. This new method of mapping, based on roughness texture, has the potential to aid mapping efforts in more remote regions, both on this planet and elsewhere in the solar system. Numéro de notice : A2014-040 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2241443 En ligne : https://doi.org/10.1109/TGRS.2013.2241443 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32945 [article]

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065-2014011B	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A local contrast method for small infrared target detection / C.L. Philip Chen in IEEE Transactions on geoscience and remote sensing, vol 52 n° 1 tome 2 (January 2014)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 52 n° 1 tome 2 (January 2014) . - pp 574 - 581 Titre : A local contrast method for small infrared target detection Type de document : Article/Communication Auteurs : C.L. Philip Chen, Auteur ; Hong Li, Auteur ; Yantao Wei, Auteur ; Tian Xia, Auteur ; Yuan Yan Tang, Auteur Année de publication : 2014 Article en page(s) : pp 574 - 581 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] amélioration du contraste [Termes IGN] contraste local [Termes IGN] détection de cible [Termes IGN] filtrage du bruit [Termes IGN] image infrarouge [Termes IGN] rapport signal sur bruit [Termes IGN] seuillage d'image Résumé : (Auteur) Robust small target detection of low signal-to-noise ratio (SNR) is very important in infrared search and track applications for self-defense or attacks. Consequently, an effective small target detection algorithm inspired by the contrast mechanism of human vision system and derived kernel model is presented in this paper. At the first stage, the local contrast map of the input image is obtained using the proposed local contrast measure which measures the dissimilarity between the current location and its neighborhoods. In this way, target signal enhancement and background clutter suppression are achieved simultaneously. At the second stage, an adaptive threshold is adopted to segment the target. The experiments on two sequences have validated the detection capability of the proposed target detection method. Experimental evaluation results show that our method is simple and effective with respect to detection accuracy. In particular, the proposed method can improve the SNR of the image significantly. Numéro de notice : A2014-041 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2242477 En ligne : https://doi.org/10.1109/TGRS.2013.2242477 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32946 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-2014011B	RAB	Revue	Centre de documentation	En réserve L003	Disponible