Bibliographies thématiques / Radar imageur

Littérature scientifique sur le sujet « Radar imageur »

Auteur : Grafiati
Publié le 25 mai 2024

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres

Choisissez une source :

Sommaire

Consultez les listes thématiques d’articles de revues, de livres, de thèses, de rapports de conférences et d’autres sources académiques sur le sujet « Radar imageur ».

À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.

Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.

Articles de revues sur le sujet "Radar imageur"

1

Montopoli, M., G. Vulpiani, D. Cimini, E. Picciotti et F. S. Marzano. « Interpretation of observed microwave signatures from ground dual polarization radar and space multi-frequency radiometer for the 2011 Grímsvötn volcanic eruption ». Atmospheric Measurement Techniques 7, no 2 (19 février 2014) : 537–52. http://dx.doi.org/10.5194/amt-7-537-2014.

Texte intégral
Résumé :
Abstract. The important role played by ground-based microwave weather radars for the monitoring of volcanic ash clouds has been recently demonstrated. The potential of microwaves from satellite passive and ground-based active sensors to estimate near-source volcanic ash cloud parameters has been also proposed, though with little investigation of their synergy and the role of the radar polarimetry. The goal of this work is to show the potentiality and drawbacks of the X-band dual polarization (DPX) radar measurements through the data acquired during the latest Grímsvötn volcanic eruptions that took place in May 2011 in Iceland. The analysis is enriched by the comparison between DPX data and the observations from the satellite Special Sensor Microwave Imager/Sounder (SSMIS) and a C-band single polarization (SPC) radar. SPC, DPX, and SSMIS instruments cover a large range of the microwave spectrum, operating respectively at 5.4, 3.2, and 0.16–1.6 cm wavelengths.
Styles APA, Harvard, Vancouver, ISO, etc.
2

Guyot, Adrien, Jordan P. Brook, Alain Protat, Kathryn Turner, Joshua Soderholm, Nicholas F. McCarthy et Hamish McGowan. « Segmentation of polarimetric radar imagery using statistical texture ». Atmospheric Measurement Techniques 16, no 19 (12 octobre 2023) : 4571–88. http://dx.doi.org/10.5194/amt-16-4571-2023.

Texte intégral
Résumé :
Abstract. Weather radars are increasingly being used to study the interaction between wildfires and the atmosphere, owing to the enhanced spatio-temporal resolution of radar data compared to conventional measurements, such as satellite imagery and in situ sensing. An important requirement for the continued proliferation of radar data for this application is the automatic identification of fire-generated particle returns (pyrometeors) from a scene containing a diverse range of echo sources, including clear air, ground and sea clutter, and precipitation. The classification of such particles is a challenging problem for common image segmentation approaches (e.g. fuzzy logic or unsupervised machine learning) due to the strong overlap in radar variable distributions between each echo type. Here, we propose the following two-step method to address these challenges: (1) the introduction of secondary, texture-based fields, calculated using statistical properties of gray-level co-occurrence matrices (GLCMs), and (2) a Gaussian mixture model (GMM), used to classify echo sources by combining radar variables with texture-based fields from (1). Importantly, we retain all information from the original measurements by performing calculations in the radar's native spherical coordinate system and introduce a range-varying-window methodology for our GLCM calculations to avoid range-dependent biases. We show that our method can accurately classify pyrometeors' plumes, clear air, sea clutter, and precipitation using radar data from recent wildfire events in Australia and find that the contrast of the radar correlation coefficient is the most skilful variable for the classification. The technique we propose enables the automated detection of pyrometeors' plumes from operational weather radar networks, which may be used by fire agencies for emergency management purposes or by scientists for case study analyses or historical-event identification.
Styles APA, Harvard, Vancouver, ISO, etc.
3

Gogineni, S., J. B. Yan, J. Paden, C. Leuschen, J. Li, F. Rodriguez-Morales, D. Braaten et al. « Bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica ». Journal of Glaciology 60, no 223 (2014) : 813–33. http://dx.doi.org/10.3189/2014jog14j129.

Texte intégral
Résumé :
AbstractThis paper presents the bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica, derived from sounding these glaciers with high-sensitivity radars. To understand the processes causing the speed-up and retreat of outlet glaciers, and to enable the development of next-generation ice-sheet models, we need information on bed topography and basal conditions. To this end, we performed measurements with the progressively improved Multichannel Coherent Radar Depth Sounder/Imager (MCoRDS/I). We processed the data from each antenna-array element using synthetic aperture radar algorithms to improve radar sensitivity and reduce along-track surface clutter. We then applied array and image-processing algorithms to extract the weak bed echoes buried in off-vertical scatter (cross-track surface clutter). At Jakobshavn Isbræ, we observed 2.7 km thick ice ~30 km upstream of the calving front and ~850 m thick ice at the calving front. We also observed echoes from multiple interfaces near the bed. We applied the MUSIC algorithm to the data to derive the direction of arrival of the signals. This analysis revealed that clutter is dominated by the ice surface at Jakobshavn Isbræ. At Byrd Glacier, we found ~3.62 km thick ice, as well as a subglacial trench ~3.05 km below sea level. We used ice thickness information derived from radar data in conjunction with surface elevation data to generate bed maps for these two critical glaciers. The performance of current radars must be improved further by ~15 dB to fully sound the deepest part of Byrd Glacier. Unmanned aerial systems equipped with radars that can be flown over lines spaced as close as 5 m apart in the cross-track direction to synthesize a two-dimensional aperture would be ideal for collecting fine-resolution data over glaciers like Jakobshavn near their grounding lines.
Styles APA, Harvard, Vancouver, ISO, etc.
4

Frame, D. J., B. N. Lawrence, G. J. Fraser et M. D. Burrage. « A comparison between mesospheric wind measurements made near Christchurch (44°S, 173°E) using the high resolution doppler imager (HRDI) and a medium frequency (MF) radar ». Annales Geophysicae 18, no 5 (31 mai 2000) : 555–65. http://dx.doi.org/10.1007/s00585-000-0555-3.

Texte intégral
Résumé :
Abstract. We report on the comparison of winds measured by a medium frequency (MF) radar near Christchurch, New Zealand, and by the high resolution doppler imager (HRDI). Previous comparisons have demonstrated that there can be significant differences in the winds obtained by the two techniques, and our results are no different. However, these data show relatively good agreement in the meridional direction, but large differences in the zonal direction, where the radar is regularly measuring the zonal wind as too easterly. To do the comparison, overpasses from the satellite must be obtained when it is close to the radar site. The radar data are averaged in time around the overpass because we know the radars sample phenomena which have spatial and temporal scales which make them invisible to HRDI. There are a limited number of overpass comparisons which limit our confidence in these results, but a detailed analysis of these data show that the proximity of the overpass is often an important factor in the differences obtained. Other factors examined include the influence of the local time of the overpass, and the amount of radar data averaged around the overpass time.Key words: Atmospheric composition and structure (instruments and techniques) · Meteorology and atmospheric dynamics (middle atmosphere dynamics; instruments and techniques)
Styles APA, Harvard, Vancouver, ISO, etc.
5

Hasebe, F., T. Tsuda, T. Nakamura et M. D. Burrage. « Validation of HRDI MLT winds with meteor radars ». Annales Geophysicae 15, no 9 (30 septembre 1997) : 1142–57. http://dx.doi.org/10.1007/s00585-997-1142-7.

Texte intégral
Résumé :
Abstract. A validation study of the mesospheric and lower-thermospheric (MLT) wind velocities measured by the High-Resolution Doppler Imager (HRDI) on board the Upper-Atmosphere Research Satellite (UARS) has been carried out, comparing with observations by meteor radars located at Shigaraki, Japan and Jakarta, Indonesia. The accuracy of the HRDI winds relative to the meteor radars is obtained by a series of simultaneous wind measurements at the time of UARS overpasses. Statistical tests on the difference in the wind vectors observed by HRDI and the meteor radars are applied to determine whether the wind speed has been overestimated by HRDI (or underestimated by the MF radars) as previously noticed in HRDI vs. MF radar comparisons. The techniques employed are the conventional t-test applied to the mean values of the paired wind vector components as well as wind speeds, and two nonparametric tests suitable for testing the paired wind speed. The square-root transformation has been applied before the t-tests of the wind speed in order to fit the wind-speed distribution function to the normal distribution. The overall results show little evidence of overestimation by HRDI (underestimation by meteor radars) of wind velocities in the MLT region. Some exceptions are noticed, however, at the altitudes around 88 km, where statistical differences occasionally reach a level of significance of 0.01. The validation is extended to estimate the precision of the wind velocities by both HRDI and meteor radars. In the procedure, the structure function defined by the mean square difference of the observed anomalies is applied in the vertical direction for the profile data. This method assumes the isotropy and the homogeneity of variance for the physical quantity and the homogeneity of variance for the observational errors. The estimated precision is about 6ms–1 for the Shigaraki meteor radar, 15ms–1 for the Jakarta meteor radar, and 20ms–1 for HRDI at 90-km altitude. These values can be used to confirm the statistical significance of the wind field obtained by averaging the observed winds.
Styles APA, Harvard, Vancouver, ISO, etc.
6

Petracca, M., L. P. D’Adderio, F. Porcù, G. Vulpiani, S. Sebastianelli et S. Puca. « Validation of GPM Dual-Frequency Precipitation Radar (DPR) Rainfall Products over Italy ». Journal of Hydrometeorology 19, no 5 (1 mai 2018) : 907–25. http://dx.doi.org/10.1175/jhm-d-17-0144.1.

Texte intégral
Résumé :
Abstract The Ka–Ku Dual-Frequency Precipitation Radar (DPR) and the Microwave Imager on board the Global Precipitation Measurement (GPM) mission core satellite have been collecting data for more than 3 years, providing precipitation products over the globe, including oceans and remote areas where ground-based precipitation measurements are not available. The main objective of this work is to validate the GPM-DPR products over a key climatic region with complex orography such as the Italian territory. The performances of the DPR precipitation rate products are evaluated over an 18-month period (July 2015–December 2016) using both radar and rain gauge data. The ground reference network is composed of 22 weather radars and more than 3000 rain gauges. DPR dual-frequency products generally show better performance with respect to the single-frequency (i.e., Ka- or Ku-band only) products, especially when ground radar data are taken as reference. A sensitivity analysis with respect to season and rainfall intensity is also carried out. It was found that the normal scan (NS) product outperforms the high-sensitivity scan (HS) and matched scan (MS) during the summer season. A deeper analysis is carried out to investigate the larger discrepancies between the DPR-NS product and ground reference data. The most relevant improvement of the DPR products’ performance was found by limiting the comparison to the upscaled radar data with a higher quality index. The resulting scores in comparison with ground radars are mean error (ME) = −0.44 mm h−1, RMSE = 3.57 mm h−1, and fractional standard error (FSE) = 142%, with the POD = 65% and FAR = 1% for rainfall above 0.5 mm h−1.
Styles APA, Harvard, Vancouver, ISO, etc.
7

Jiang, Chong, Lin Ren, Jingsong Yang, Qing Xu et Jinyuan Dai. « Wind Speed Retrieval Using Global Precipitation Measurement Dual-Frequency Precipitation Radar Ka-Band Data at Low Incidence Angles ». Remote Sensing 14, no 6 (18 mars 2022) : 1454. http://dx.doi.org/10.3390/rs14061454.

Texte intégral
Résumé :
In this study, sea surface wind speed was retrieved using the Global Precipitation Measurement (GPM) dual-frequency precipitation radar (DPR) Ka-band data. In order to establish the Ka-band model at low incidence angles, the dependence of the DPR Ka-band normalized radar cross section (NRCS) on the wind speed, incidence angle, sea surface temperature (SST), significant wave height (SWH), and sea surface current speed (CSPD) was analyzed first. We confirmed that the normalized radar cross section depends on the wind speed, incidence angle, and SST. Second, an empirical model at low incidence angles was established. This model links the Ka-band NRCS to the incidence angle, wind speed, and SST. Additionally, the wind speed was retrieved by the model and was validated via the GPM Microwave Imager (GMI) wind product. The validation yielded a root mean square error (RMSE) of 1.45 m/s and the RMSE was better at a lower incidence angle and a higher SST. This model may expand the use of GPM DPR data in enriching the sea surface wind speed data set. It is also helpful for other Ka-band spaceborne radars at low incidence angles to measure wind speed in the future.
Styles APA, Harvard, Vancouver, ISO, etc.
8

Hayashi, Yoshiaki, Taichi Tebakari et Akihiro Hashimoto. « A Comparison Between Global Satellite Mapping of Precipitation Data and High-Resolution Radar Data – A Case Study of Localized Torrential Rainfall over Japan ». Journal of Disaster Research 16, no 4 (1 juin 2021) : 786–93. http://dx.doi.org/10.20965/jdr.2021.p0786.

Texte intégral
Résumé :
This paper presents a case study comparing the latest algorithm version of Global Satellite Mapping of Precipitation (GSMaP) data with C-band and X-band Multi-Parameter (MP) radar as high-resolution rainfall data in terms of localized heavy rainfall events. The study also obliged us to clarify the spatial and temporal resolution of GSMaP data using high-accuracy ground-based radar, and evaluate the performance and reporting frequency of GSMaP satellites. The GSMaP_Gauge_RNL data with less than 70 mm/day of daily rainfall was similar to the data of both radars, but the GSMaP_Gauge_RNL data with over 70 mm/day of daily rainfall was not, and the calibration by rain-gauge data was poor. Furthermore, both direct/indirect observations by the Global Precipitation Measurement/Microwave Imager (GPM/GMI) and the frequency thereof (once or twice) significantly affected the difference between GPM/GMI data and C-band radar data when the daily rainfall was less than 70 mm/day and the hourly rainfall was less than 20 mm/h. Therefore, it is difficult for GSMaP_Gauge to accurately estimate localized heavy rainfall with high-density particle precipitation.
Styles APA, Harvard, Vancouver, ISO, etc.
9

Lee, Yoonjin, Christian D. Kummerow et Milija Zupanski. « Latent heating profiles from GOES-16 and its impacts on precipitation forecasts ». Atmospheric Measurement Techniques 15, no 23 (12 décembre 2022) : 7119–36. http://dx.doi.org/10.5194/amt-15-7119-2022.

Texte intégral
Résumé :
Abstract. Latent heating (LH) is an important factor in both weather forecasting and climate analysis, being the essential factor affecting both the intensity and structure of convective systems. Yet, inferring LH rates from our current observing systems is challenging at best. For climate studies, LH has been retrieved from the precipitation radar on the Tropical Rainfall Measuring Mission (TRMM) using model simulations in a lookup table (LUT) that relates instantaneous radar data to corresponding heating profiles. These radars, first on TRMM and then the Global Precipitation Measurement Mission (GPM), provide a continuous record of LH. However, the temporal resolution is too coarse to have significant impacts on forecast models. In operational forecast models such as High-Resolution Rapid Refresh (HRRR), convection is initiated from LH derived from ground-based radars. Despite the high spatial and temporal resolution of ground-based radars, their data are only available over well-observed land areas. This study develops a method to derive LH from the Geostationary Operational Environmental Satellite-16 (GOES-16) in near-real time. Even though the visible and infrared channels on the Advanced Baseline Imager (ABI) provide mostly cloud top information, rapid changes in cloud top visible and infrared properties, when formulated as an LUT similar to those used by the TRMM and GPM radars, can successfully be used to derive LH profiles for convective regions based on model simulations with a convective classification scheme and channel 14 (11.2 µm) brightness temperatures. Convective regions detected by GOES-16 are assigned LH profiles from a predefined LUT, and they are compared with LH used by the HRRR model and one of the dual-frequency precipitation radar (DPR) products, the Goddard convective–stratiform heating (CSH). LH obtained from GOES-16 shows similar magnitude to LH derived from the Next Generation Weather Radar (NEXRAD) and CSH, and the vertical distribution of LH is also very similar with CSH. A three-month analysis of total LH from convective clouds from GOES-16 and NEXRAD shows good correlation between the two products. Finally, LH profiles from GOES-16 and NEXRAD are applied to WRF simulations for convective initiation, and their results are compared to investigate their impacts on precipitation forecasts. Results show that LH from GOES-16 has similar impacts to NEXRAD in terms of improving the forecast. While only a proof of concept, this study demonstrates the potential of using LH derived from GOES-16 for convective initialization.
Styles APA, Harvard, Vancouver, ISO, etc.
10

Mityagina, M. I. « Intensity of convective motions in marine atmospheric boundary layer retrieved from ocean surface radar imagery ». Nonlinear Processes in Geophysics 13, no 3 (24 juillet 2006) : 303–8. http://dx.doi.org/10.5194/npg-13-303-2006.

Texte intégral
Résumé :
Abstract. The paper focuses on the occurrence and development of coherent structures observed in the atmosphere above ocean under natural conditions. Microwave imaging radars are suggested as data take instruments. The phenomena of marine atmospheric cells and rolls onset, horizontal planform, aspect ratio and scaling phenomena are examined. Convective patterns manifested in radar images and information derived on the intensity of atmospheric motion are discussed.
Styles APA, Harvard, Vancouver, ISO, etc.
Plus de sources

Thèses sur le sujet "Radar imageur"

1

Schreiber, Floriane. « Estimation des conditions océanographiques par inversion de données issues d'un radar imageur non calibré ». Electronic Thesis or Diss., Toulon, 2020. http://www.theses.fr/2020TOUL0016.

Texte intégral
Résumé :
De nombreux modèles empiriques de distribution statistique du fouillis de mer existent mais ne sont pas directement paramétrable par l’état de mer, et ainsi il n’est pas possible d’y pratiquer une méthode d’inversion. Pour modéliser la distribution statistique de l’intensité, nous utilisons un modèle deux-échelles (TSM) paramétré directement par l’état de mer via la mss (mean square slope). Ce modèle permet de retrouver de manière cohérente la NRCS mais ne parvient pas à décrire de manière la distribution du fouillis de mer simultanément dans les deux canaux de polarisations directs dû à une surestimation du rapport de polarisation (RP) de Bragg.Pour corriger ce problème, nous avons développé une formulation originale du RP qui inclue un unique paramètre effectuant une transition dynamique entre le régime de Bragg et de Kirchhoff. Cette formulation intégrée au modèle TSM permet de corriger le RP et d’obtenir une modélisation cohérente de la statistique du fouillis de mer, simultanément dans les deux polarisations. A l’aide d’une méthode d’inversion, le modèle permet d'estimer l’état de mer d’un radar imageur. La pertinence de ce modèle est établie dans différentes configurations, mais aussi pour des données présentant des incertitudes de calibration
Many empirical models describing sea clutter statistical distribution exist but they do not directly depend on the sea sate. They are not suitable to perform inversion. To model the statistical distribution of the backscattered intensity, we use a two-scale model (TSM) which is linked to the sea state via the mss (mean square slope). This model allows to retrieve the NRCS but does not perfectly describes the sea clutter distribution simultaneously in the two direct polarization channels. This is due to an overestimation of the Bragg polarization ratio (PR)
Styles APA, Harvard, Vancouver, ISO, etc.
2

Benahmed, Daho Omar. « Radar ULB pour la vision à travers les murs : mise au point d'une chaîne de traitement de l'information d'un radar imageur ». Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS036/document.

Texte intégral
Résumé :
Nous nous intéressons dans cette thèse à la vision à travers les murs (VTM) par radar ULB, avec comme objectif la mise au point d’une chaîne de traitement de l’information (CTI) complète pouvant être utilisée par différents types de radar imageur VTM. Pour ce faire, nous souhaitons prendre en compte le moins possible d’information a priori, ni sur les cibles, ni sur leur contexte environnemental. De plus, la CTI doit répondre à des critères d’adaptabilité et de modularité pour pouvoir traiter les informations issues de deux types de radar, notamment, le pulsé et le FMCW, développés dans deux projets dans lesquels s’inscrivent les travaux de cette thèse. L’imagerie radar est un point important dans ce contexte, nous l’abordons par la combinaison des algorithmes de rétroprojection et trilatération, et montrons l’amélioration apportée avec l’utilisation d’un détecteur TFAC prenant en compte la forme des signatures des cibles. La mise au point de la CTI est notre principale contribution. Le flux d’images radar obtenu est scindé en deux parties. La première séquence dynamique contient les cibles mobiles qui sont ensuite suivies par une approche multihypothèse. La seconde séquence statique contient les cibles stationnaires ainsi que les murs intérieurs qui sont détectés par une méthode s’appuyant sur la transformée de Radon. Nous avons produit un simulateur VTM fonctionnant dans le domaine temporel et fréquentiel pour mettre au point les algorithmes de la CTI et tester leur robustesse. Plusieurs scénarios de simulation ainsi que de mesures expérimentales, montrent que la CTI construite est pertinente et robuste. Elle est ainsi validée pour les deux systèmes radar
This report is focused on Through-the-wall surveillance (TTS) using UWB radar, with the objective of developing a complete information processing pipeline (IPP) which can be used by different types of imaging radar. To do this, we want to take into account any a priori information, nor on the target, or their environmental context. In addition, the IPP must meet criteria of adaptability and modularity to process information from two types of radar, including pulsed and FMCW developed in two projects that are part of the work of this thesis. Radar imaging is an important point in this context ; we approach it by combining backprojection and trilateration algorithms and show the improvement with the use of a CFAR detector taking into account the shape of the targets signatures.The development of the IPP is our main contribution. The flow of radar images obtained is divided into two parts. The first dynamic sequence contains moving targets are tracked by a multiple hypothesis approach. The second static sequence contains stationary targets and interior walls that are highlighted by Radon transformbases approach. We developed a simulator operating in time and frequency domain to design the algorithms of the IPP and test their robustness. Several simulated scenarios and experimental measurements show that our IPP is relevant and robust. It is thus validated for both radar systems
Styles APA, Harvard, Vancouver, ISO, etc.
3

Cattin, Viviane. « Traitement et exploitation des signaux issus d'un imageur électromagnétique ». Grenoble INPG, 1998. http://www.theses.fr/1998INPG0128.

Texte intégral
Résumé :
Un imageur electromagnetique haute resolution est envisage afin de detecter et de localiser des objets situes dans des structures heterogenes. Il doit permettre la mesure non destructive de contrastes en permittivite et en conductivite, a une profondeur d'investigation de quelques decimetres, avec une resolution de l'ordre du centimetre. Dans ce but, nous cherchons a identifier les points delicats de son developpement. Afin de choisir le systeme et interpreter sa reponse, nous etudions la caracterisation electromagnetique de materiaux, et les phenomenes de reflexions secondaires et de resonance presents dans les milieux formant les structures considerees. Ceci nous permet de specifier un systeme electromagnetique base sur le principe d'un radar a sauts de frequence. Les antennes etant placees a proximite du milieu, nous nous interessons aux phenomenes de couplage afin d'evaluer quelles sont les perturbations induites sur une reponse radar. Des algorithmes d'imagerie qualitative (focalisation par synthese d'ouverture, migration f-k, tomographie microonde) sont utilises afin d'interpreter la reponse de l'imageur sous forme de courants induits. Ils permettent de positionner les structures et les objets cherches. Nous proposons l'emploi de methodes parametriques (methode de pencil) afin d'ameliorer la resolution. Enfin, des experimentations sur des milieux heterogenes avec differentes polarisations et bandes de frequence montrent la validite et les limites de cet imageur.
Styles APA, Harvard, Vancouver, ISO, etc.
4

Beaudoin, André. « Observation de la terre par radar imageur : estimation de la biomasse forestière : [thèse soutenue sur un ensemble de travaux] ». Toulouse 3, 1992. http://www.theses.fr/1992TOU30244.

Texte intégral
Résumé :
Un des parametres-clefs a apprehender dans l'etude des ecosystemes forestiers est la biomasse forestiere, tant dans les etudes de changements globaux que dans la gestion des ressources forestieres. L'observation par radar imageur des ecosystemes forestiers s'avere une application prometteuse des techniques de teledetection, considerant la penetration des micro-ondes dans les couverts vegetaux. De plus, le fonctionnement par tout temps des systemes radar s'avere necessaire pour l'observation des regions a forte couverture nuageuse. Afin de demontrer l'apport de la teledetection radar pour l'estimation de la biomasse forestiere, une experience a ete menee en 1989 sur le massif landais dans le sud-ouest de la france, constitue de forets de pin maritime (pinus pinaster). Des donnees aeroportees rso (radar a synthese d'ouverture) multifrequences et polarimetriques du nasa/jpl ont ete acquises sur une partie du massif, alors que les parametres forestiers, incluant la biomasse ligneuse et foliaire, ont ete mesures sur plusieurs parcelles. La phase d'analyse des donnees apres l'etalonnage complet des images rso, a revele une forte correlation entre l'echo radar et la biomasse ligneuse sur pied. Afin d'interpreter ces observations, un modele theorique d'interaction des micro-ondes avec le milieu forestier a ete developpe et valide par les mesures experimentales. La phase d'interpretation a permis de cerner le lien physique existant entre l'echo radar et la biomasse ligneuse. Par la suite, le modele a ete utilise dans une etude de simulation, visant a tenir compte des variations environnementales susceptibles de perturber la sensibilite de l'echo radar a la biomasse ligneuse. Il a ete demontre que la topographie et la structure du couvert sont des parametres a prendre en compte selon les differentes configurations radar utilisees, afin d'optimiser l'estimation de la biomasse. Finalement, un exemple d'inversion de la biomasse a partir des donnees radar en bande p pour le cas du pin maritime est presente
Styles APA, Harvard, Vancouver, ISO, etc.
5

Dellinger, Flora. « Descripteurs locaux pour l'imagerie radar et applications ». Thesis, Paris, ENST, 2014. http://www.theses.fr/2014ENST0037/document.

Texte intégral
Résumé :
Nous étudions ici l’intérêt des descripteurs locaux pour les images satellites optiques et radar. Ces descripteurs, par leurs invariances et leur représentation compacte, offrent un intérêt pour la comparaison d’images acquises dans des conditions différentes. Facilement applicables aux images optiques, ils offrent des performances limitées sur les images radar, en raison de leur fort bruit multiplicatif. Nous proposons ici un descripteur original pour la comparaison d’images radar. Cet algorithme, appelé SAR-SIFT, repose sur la même structure que l’algorithme SIFT (détection de points-clés et extraction de descripteurs) et offre des performances supérieures pour les images radar. Pour adapter ces étapes au bruit multiplicatif, nous avons développé un opérateur différentiel, le Gradient par Ratio, permettant de calculer une norme et une orientation du gradient robustes à ce type de bruit. Cet opérateur nous a permis de modifier les étapes de l’algorithme SIFT. Nous présentons aussi deux applications pour la télédétection basées sur les descripteurs. En premier, nous estimons une transformation globale entre deux images radar à l’aide de SAR-SIFT. L’estimation est réalisée à l’aide d’un algorithme RANSAC et en utilisant comme points homologues les points-clés mis en correspondance. Enfin nous avons mené une étude prospective sur l’utilisation des descripteurs pour la détection de changements en télédétection. La méthode proposée compare les densités de points-clés mis en correspondance aux densités de points-clés détectés pour mettre en évidence les zones de changement
We study here the interest of local features for optical and SAR images. These features, because of their invariances and their dense representation, offer a real interest for the comparison of satellite images acquired under different conditions. While it is easy to apply them to optical images, they offer limited performances on SAR images, because of their multiplicative noise. We propose here an original feature for the comparison of SAR images. This algorithm, called SAR-SIFT, relies on the same structure as the SIFT algorithm (detection of keypoints and extraction of features) and offers better performances for SAR images. To adapt these steps to multiplicative noise, we have developed a differential operator, the Gradient by Ratio, allowing to compute a magnitude and an orientation of the gradient robust to this type of noise. This operator allows us to modify the steps of the SIFT algorithm. We present also two applications for remote sensing based on local features. First, we estimate a global transformation between two SAR images with help of SAR-SIFT. The estimation is realized with help of a RANSAC algorithm and by using the matched keypoints as tie points. Finally, we have led a prospective study on the use of local features for change detection in remote sensing. The proposed method consists in comparing the densities of matched keypoints to the densities of detected keypoints, in order to point out changed areas
Styles APA, Harvard, Vancouver, ISO, etc.
6

Dellinger, Flora. « Descripteurs locaux pour l'imagerie radar et applications ». Electronic Thesis or Diss., Paris, ENST, 2014. http://www.theses.fr/2014ENST0037.

Texte intégral
Résumé :
Nous étudions ici l’intérêt des descripteurs locaux pour les images satellites optiques et radar. Ces descripteurs, par leurs invariances et leur représentation compacte, offrent un intérêt pour la comparaison d’images acquises dans des conditions différentes. Facilement applicables aux images optiques, ils offrent des performances limitées sur les images radar, en raison de leur fort bruit multiplicatif. Nous proposons ici un descripteur original pour la comparaison d’images radar. Cet algorithme, appelé SAR-SIFT, repose sur la même structure que l’algorithme SIFT (détection de points-clés et extraction de descripteurs) et offre des performances supérieures pour les images radar. Pour adapter ces étapes au bruit multiplicatif, nous avons développé un opérateur différentiel, le Gradient par Ratio, permettant de calculer une norme et une orientation du gradient robustes à ce type de bruit. Cet opérateur nous a permis de modifier les étapes de l’algorithme SIFT. Nous présentons aussi deux applications pour la télédétection basées sur les descripteurs. En premier, nous estimons une transformation globale entre deux images radar à l’aide de SAR-SIFT. L’estimation est réalisée à l’aide d’un algorithme RANSAC et en utilisant comme points homologues les points-clés mis en correspondance. Enfin nous avons mené une étude prospective sur l’utilisation des descripteurs pour la détection de changements en télédétection. La méthode proposée compare les densités de points-clés mis en correspondance aux densités de points-clés détectés pour mettre en évidence les zones de changement
We study here the interest of local features for optical and SAR images. These features, because of their invariances and their dense representation, offer a real interest for the comparison of satellite images acquired under different conditions. While it is easy to apply them to optical images, they offer limited performances on SAR images, because of their multiplicative noise. We propose here an original feature for the comparison of SAR images. This algorithm, called SAR-SIFT, relies on the same structure as the SIFT algorithm (detection of keypoints and extraction of features) and offers better performances for SAR images. To adapt these steps to multiplicative noise, we have developed a differential operator, the Gradient by Ratio, allowing to compute a magnitude and an orientation of the gradient robust to this type of noise. This operator allows us to modify the steps of the SIFT algorithm. We present also two applications for remote sensing based on local features. First, we estimate a global transformation between two SAR images with help of SAR-SIFT. The estimation is realized with help of a RANSAC algorithm and by using the matched keypoints as tie points. Finally, we have led a prospective study on the use of local features for change detection in remote sensing. The proposed method consists in comparing the densities of matched keypoints to the densities of detected keypoints, in order to point out changed areas
Styles APA, Harvard, Vancouver, ISO, etc.
7

Matarese, Joseph R. (Joseph Richard). « Topographic reconstruction from radar imagery ». Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/59857.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
8

Kim, Jungwhan John. « Road detection on radar imagery ». Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/53080.

Texte intégral
Résumé :
A facet based road network detection procedure is described for radar imagery. The procedure includes a line detection part and a road detection and connection part. The line detection part analytically detects linear features using a facet Valley finding technique. Valleys are defined as zero crossings of the first directional derivatives of a bicubic facet model taken in a direction extremizing the second directional derivative. The road detection and connection part statistically screens the linear features on a component by component basis, and then optimally connects the screened linear features using a dynamic programming algorithm. This thesis also includes as a preprocessing technique for noisy images, an adaptive noise removal algorithm, and suggests a practical method of estimating a local noise variance.
Master of Science
Styles APA, Harvard, Vancouver, ISO, etc.
9

Reeves, Bryan Anthony. « Slope stability radar / ». [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17049.pdf.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
10

Yuzcelik, Cihangir Kemal. « Radar absorbing material design ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FYuzcelik.pdf.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
Plus de sources

Livres sur le sujet "Radar imageur"

1

1949-, Quegan Shaun, dir. Understanding synthetic aperture radar images. Boston : Artech House, 1998.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
2

Mun, Kok Leong. Stepped frequency imaging radar simulation. Monterey, Calif : Naval Postgraduate School, 2000.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
3

P, Ford J., et Jet Propulsion Laboratory (U.S.), dir. Spaceborne radar observations : A guide for Magellan radar-image analysis. Pasadena, Calif : National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1989.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
4

Matre, Henri, dir. Processing of Synthetic Aperture Radar Images. London, UK : ISTE, 2008. http://dx.doi.org/10.1002/9780470611111.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
5

Henri, Maître, dir. Processing of synthetic aperture radar images. Hoboken, NJ, USA : Wiley, 2008.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
6

Henri, Maître, dir. Processing of synthetic aperture radar images. Newport Beach, CA : ISTE, 2007.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
7

Rihaczek, August W. Radar resolution and complex-image analysis. Boston : Artech House, 1996.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
8

Neva, Donovan, Evans Diane, Held D et Jet Propulsion Laboratory (U.S.), dir. NASA/JPL Aircraft SAR Workshop proceedings : February 4-5, 1985, at the Jet Propulsion Laboratory, Pasadena, California. Pasadena, Calif : National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1985.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
9

Neva, Donovan, Evans Diane, Held D et Jet Propulsion Laboratory (U.S.), dir. NASA/JPL Aircraft SAR Workshop proceedings : February 4-5, 1985, at the Jet Propulsion Laboratory, Pasadena, California. Pasadena, Calif : National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1985.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
10

Engineers, Institution of Electrical, dir. Introduction to radar target recognition. London : Institution of Electrical Engineers, 2005.

Trouver le texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
Plus de sources

Chapitres de livres sur le sujet "Radar imageur"

1

Orhaug, Torleiv. « Radar Imagery ». Dans Inverse Methods in Electromagnetic Imaging, 823–39. Dordrecht : Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5271-3_8.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
2

Orhaug, Torleiv. « Radar Imagery ». Dans Inverse Methods in Electromagnetic Imaging, 823–39. Dordrecht : Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-010-9444-3_47.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
3

Knott, Eugene F. « Radar Imagery ». Dans Radar Cross Section Measurements, 385–429. Boston, MA : Springer US, 1993. http://dx.doi.org/10.1007/978-1-4684-9904-9_10.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
4

Richards, John A. « Radar Image Interpretation ». Dans Remote Sensing with Imaging Radar, 265–308. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02020-9_8.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
5

Drury, S. A. « Radar remote sensing ». Dans Image Interpretation in Geology, 165–94. Dordrecht : Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-010-9393-4_7.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
6

Souyris, Jean-Claude. « The Physics of Radar Measurement ». Dans Remote Sensing Imagery, 83–122. Hoboken, USA : John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118899106.ch4.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
7

Tupin, Florence, Jean-Marie Nicolas et Jean-Claude Souyris. « Models and Processing of Radar Signals ». Dans Remote Sensing Imagery, 181–202. Hoboken, USA : John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118899106.ch7.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
8

Richards, John A. « Correcting and Calibrating Radar Imagery ». Dans Remote Sensing with Imaging Radar, 109–34. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02020-9_4.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
9

Trevett, J. W. « Image Processing ». Dans Imaging Radar for Resources Surveys, 63–77. Dordrecht : Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4089-5_4.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
10

Overgård, Søren, et Erik Wienberg. « The Distribution of Weather Radar Images to Agricultural End Users ». Dans Weather Radar Networking, 545–56. Dordrecht : Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0551-1_59.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.

Actes de conférences sur le sujet "Radar imageur"

1

Dankert, Heiko, Jochen Horstmann et Wolfgang Rosenthal. « Detection of Extreme Waves in SAR Images and Radar-Image Sequences ». Dans ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/omae2002-28160.

Texte intégral
Résumé :
Extreme waves are often enclosed by other waves which are also higher than the average. These wave groups have to be taken into account for instance for the design of offshore platforms, breakwaters or ships, because successive high waves can cause more damage on those structures than the same waves separated by smaller waves. Further they can excite the resonance frequencies of moored structures like platforms due to non-linear effects or cause capsize. They are therefore of interest for engineers and scientists (e.g. Goda 1983). A method is presented to localize wave groups spatial and spatio-temporal utilizing synthetic aperture radar (SAR) images and nautical radar-image sequences. The approach to detect wave groups is based on the detection of the wave envelope. It is assumed that the sea surface elevation can be treated as a Gaussian process. The method is applied to SAR images acquired by the European satellite ERS-1 and to radar-image sequences recorded by tower-based nautical radars. In contrast to 1D sensors like buoys the SAR records an image and gives therefore a 2D description of the sea surface by measuring the radar backscatter from the sea surface. The measurements taken by a nautical radar provide the possibility to record time series of images and therefore to get a 3D description of the sea surface. Radar-image sequences are acquired by recording the spatial and temporal evolution of the sea surface backscatter, which is modulated through the surface wave field. Nautical radar-image sequences allow to detect wave groups within a time span that makes it possible to start safety programs before the group reaches a platform. The existing data sets are exploited with respect to the recognition of extreme wave events.
Styles APA, Harvard, Vancouver, ISO, etc.
2

O'Connell, Barbara J. « Ice Hazard Radar ». Dans SNAME 9th International Conference and Exhibition on Performance of Ships and Structures in Ice. SNAME, 2010. http://dx.doi.org/10.5957/icetech-2010-179.

Texte intégral
Résumé :
Ships transiting polar regions would benefit from a marine ice navigation radar that could help them differentiate between dangerous multi-year ice and thick first-year ice. Conventional marine radars are designed for target detection and avoidance. Enhanced marine radars provide a higher definition image of the ice that the vessel is transiting through and may help the user to identify certain ice features, but they cannot distinguish first year ice from old ice. This paper presents one approach for the automated identification of sea ice types by a marine radar using cross-polarization technology.
Styles APA, Harvard, Vancouver, ISO, etc.
3

Yoshikado, Shin, et Tadashi Aruga. « Investigation of Conceptual Synthetic Aperture Infrared Laser Radars ». Dans Coherent Laser Radar. Washington, D.C. : Optica Publishing Group, 1995. http://dx.doi.org/10.1364/clr.1995.wa1.

Texte intégral
Résumé :
Synthetic aperture radars(SAR) have widely been used for high-resolution imaging of the earth's and planets' surfaces. In microwave remote sensing fields, aperture synthesis usually means the signal processing for obtaining an image of the area sequentially illuminated by the radar wave emitted from a single moving real aperture. It is a technique now in well-established stages for radio wavelengths.
Styles APA, Harvard, Vancouver, ISO, etc.
4

Radhakrishnan, Gowtham, Bernt J. Leira, Zhen Gao, Svein Sævik et Konstantinos Christakos. « Retrieval of Ocean Wave Spectra From X-Band Marine Radar Images Using Inversion Schemes Based on Auto-Spectral Analysis ». Dans ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-104877.

Texte intégral
Résumé :
Abstract Estimation of ocean wave conditions is extremely crucial for the planning and execution of demanding marine operations. Further, the Response Based Decision-Making requires accurate wave inputs to derive the responses using a numerical model. The X-band marine radars, installed on top of the vessels, are cost-effective means to assess the incoming wave field. Dedicated full-scale measurements were conducted using the research vessel Gunnerus in the Breisundet field, located on the west coast of Norway. After interaction with the ocean waves, the electromagnetic waves from the radar are backscattered based on the Bragg scattering mechanism. The radar digitizes the backscattered signal in the form of intensity images. 3-Dimensional (3-D) Fast Fourier Transform (FFT) was adopted to convert the temporal sequence of backscattered images to the wavenumber-frequency representations. The current velocity components estimated using the least-squares approach showed better agreement with the buoy-based current measurements. Then the wave-related components were extracted based on the linear wave dispersion relationship. Subsequently, the spectra were corrected for the shadowing effect using modulation transfer functions. Finally, the radar-based wave measurements were scaled using the nearby wave buoy records. The estimation of wave spectra improved considerably after the application of the Modulation Transfer Function (MTF). The spectra at the mid-range gave the best results when studying the effects due to range dependency. The spectra processed from radar images were validated using wave buoy measurements.
Styles APA, Harvard, Vancouver, ISO, etc.
5

Steyn, J. M., et W. A. J. Nel. « Using image quality measures and features to choose good images for classification of ISAR imagery ». Dans 2014 International Radar Conference (Radar). IEEE, 2014. http://dx.doi.org/10.1109/radar.2014.7060244.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
6

Naaijen, P., et A. P. Wijaya. « Phase Resolved Wave Prediction From Synthetic Radar Images ». Dans ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23470.

Texte intégral
Résumé :
A method is presented for the inversion of images of the sea surface taken by nautical radar into wave elevation that is specifically suitable for the prediction of the wave elevation outside the observation domain covered by the radar. By means of a beam-wise analysis of the image obtained by a scanning radar, the image information is translated into wave elevation. Subsequently a 2D FFT is applied in order to obtain the directional wave components required for a linear propagation of the wave field. Assuming knowledge of the significant wave height, a method to obtain the correct scaling of the wave prediction is proposed. The proposed method is verified using synthetic radar images which are modelled by applying shadowing and tilt effect to synthesised short crested linear waves.
Styles APA, Harvard, Vancouver, ISO, etc.
7

Story, W. Rob, Thomas C. Fu et Erin E. Hackett. « Radar Measurement of Ocean Waves ». Dans ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49895.

Texte intégral
Résumé :
Over the past two decades a number of advances have been made in the use of radar systems for the measurement of ocean waves, building on early work at universities and the Naval Research Lab (NRL) to investigate the potential for extracting wave field measurements from the sea clutter seen in shipboard radar images. This early work was the foundation for modern wave radar systems, with hardware systems ranging from commercial off the shelf (COTS) incoherent navigation radar to specially developed, calibrated, coherent instrumentation radar and phased-array systems. Software algorithms and image analysis techniques have also been in constant development, which have evolved from 2D analysis of digitized images into modern techniques performing real-time 3D transformation of high resolution images. Most of these systems are being utilized to measure the directional wave spectra, with some systems also providing wave height estimates and sea surface elevation maps. More recently, the Naval Surface Warfare Center, Carderock Division (NSWCCD) and others have begun to utilize these techniques for shipboard measurement of open ocean waves. All these efforts have led to higher fidelity data, as well as data that were previously unobtainable. In this paper we provide an overview and history of the development of COTS incoherent wave radar systems, analysis techniques, and capabilities, from early characterization of sea clutter return to the latest developments in image inversion and sea surface topography. This review and summary provides a foundation on which to develop analysis techniques for the higher fidelity data, using lessons learned to improve future analysis. While not intending to be exhaustive, this paper seeks to highlight the insights gained from both historical and recent applications of these techniques, as well as the difficulties and issues associated with shipboard measurements such as ship motion, logistical constraints, and environmental factors.
Styles APA, Harvard, Vancouver, ISO, etc.
8

Wijaya, A. P. « Towards Nonlinear Wave Reconstruction and Prediction From Synthetic Radar Images ». Dans ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54496.

Texte intégral
Résumé :
The use of remotely wave sensing by a marine radar is increasingly needed to provide wave information for the sake of safety and operational effectiveness in many offshore activities. Reconstruction of radar images needs to be carried out since radar images are a poor representation of the sea surface elevation: effects like shadowing and tilt determine the backscattered intensity of the images. In [1], the sea state reconstruction and wave propagation to the radar has been tackled successfully for synthetic radar images of linear seas, except for a scaling in the vertical direction. The determination of the significant wave height from the shadowed images only has been described in [2]. This paper will summarize these methods, and provides the first results for the extension to nonlinear seas.
Styles APA, Harvard, Vancouver, ISO, etc.
9

Tajbakhsh, S., K. Ouchi et R. E. Burge. « Dependence of speckle statistics on backscatter cross-section fluctuations in SAR images of stationary homogeneous random rough surfaces ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.thu6.

Texte intégral
Résumé :
A theory is described to relate the statistical properties of the fields backscattered from rough surfaces to those of speckle in synthetic aperture radar (SAR) images. The expressions are derived for the autocorrelation functions of speckle intensity in both single-look and multilook images of stationary random rough surfaces in terms of the SAR system parameters and the autocorrelation function of backscatter radar cross-section fluctuations. It is shown that if the correlation scale of cross-section fluctuations is comparable with or greater than the SAR resolution, the correlation functions of speckle intensity depend on those of the cross-section fluctuations. This property may, therefore, be applied to image classification. Comparison of the theory to computer simulation shows good agreement.
Styles APA, Harvard, Vancouver, ISO, etc.
10

Harvey, E., et G. April. « Speckle reduction in SAR imagery ». Dans OSA Annual Meeting. Washington, D.C. : Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.thpo35.

Texte intégral
Résumé :
The high resolution in synthetic aperture radar (SAR) systems is reduced by the speckle appearing in SAR images. This speckle noise is generated by the coherent processing of radar signals and is similar to optical speckle. This multiplicative noise in radar images may be reduced by computer spatial processing: noise smoothing algorithms are developed based on local homomorphic processing of the images. The algorithms applied to the SAR images suppress the speckle noise without deterioration of the edges and fine details.
Styles APA, Harvard, Vancouver, ISO, etc.

Rapports d'organisations sur le sujet "Radar imageur"

1

Groeneveld, Davis et Williams. L51974 Automated Detection of Encroachment Events Using Satellite Remote Sensing. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), août 2002. http://dx.doi.org/10.55274/r0011300.

Texte intégral
Résumé :
As an integral part of the ongoing effort to develop an operational capability of remote sensing based pipeline encroachment monitoring, this investigation focused on the development of automated target detection using synthetic aperture radar (RADARSAT) and optical (QUICKBIRD, EROS) satellite imagery. Specifically, the study aimed at meeting the following objectives: To develop automated target detection algorithms for optical and radar imagery that replicate detection rates obtained through visual image interpretation; To investigate the utility of newly available high-resolution optical satellite imagery for encroachment monitoring; To reduce false alarms through the processing of multitemporal radar images; and To identify and prioritize areas of future research and development required for the operational application of the technology.
Styles APA, Harvard, Vancouver, ISO, etc.
2

Doerry, Armin, et Douglas Bickel. Synthetic Aperture Radar Image Geolocation Using Fiducial Images. Office of Scientific and Technical Information (OSTI), octobre 2022. http://dx.doi.org/10.2172/1890785.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
3

Werle, D. Radar remote sensing for application in forestry : a literature review for investigators and potential users of SAR data in Canada. Natural Resources Canada/CMSS/Information Management, 1989. http://dx.doi.org/10.4095/329188.

Texte intégral
Résumé :
Information provided in this document allows potential users of synthetic aperture radar (SAR) imagery as well as investigators participating in the Canadian Radar Data Development Program (RDDP) to obtain an overview of achievements, limitations and future potential of radar remote sensing for application in forestry, as portrayed in the published literature. Investigations concerned with radar remote sensing and its potential for application in forestry are reviewed. The main focus of these studies was the determination of microwave backscatter characteristics of forestry targets using different radar parameters, such as frequency, polarizations and incidence angle. Examples of selected targets include the following: coniferous and deciduous tree species, stands of different structure, age, tree height, clearcuts, or forestry environments in general as they change with the seasons. More than 75 studies based on airborne imaging radar, spaceborne radar as well as scatterometer data have been considered. Previous reviews which summarize information available in western Europe and North America are briefly introduced. Then, recent investigations covering the time period from the early 1980's onward are portrayed and discussed. The main results are summarized in a set of conclusions, followed by list of selected references and a list of Canadian institutions and organizations currently involved in radar remote sensing R&D for application in forestry.
Styles APA, Harvard, Vancouver, ISO, etc.
4

Doerry, Armin, et Douglas Bickel. Radar Motion Measurements and Synthetic Aperture Radar Image Geolocation Accuracy. Office of Scientific and Technical Information (OSTI), octobre 2020. http://dx.doi.org/10.2172/1675035.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
5

Doerry, Armin Walter. Apodized RFI filtering of synthetic aperture radar images. Office of Scientific and Technical Information (OSTI), février 2014. http://dx.doi.org/10.2172/1204095.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
6

DUDLEY, PETER A. Synthetic Aperture Radar Image Formation in Reconfigurable Logic. Office of Scientific and Technical Information (OSTI), juin 2001. http://dx.doi.org/10.2172/782724.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
7

Ralston, James M., et Elizabeth L. Ayers. Antenna Effects on Polarimetric Imagery in Ultrawide Synthetic Aperture Radar. Fort Belvoir, VA : Defense Technical Information Center, septembre 2002. http://dx.doi.org/10.21236/ada415541.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
8

Teillet, P. M., G. Fedosejevs, D. Gauthier, M. D'Iorio, B. Rivard, P. Budkewitsch et B. Brisco. Initial Examination of Radar Imagery of Optical Radiometric Calibration Sites. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1995. http://dx.doi.org/10.4095/218130.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
9

DELAURENTIS, JOHN M., et ARMIN W. DOERRY. Stereoscopic Height Estimation from Multiple Aspect Synthetic Aperture Radar Images. Office of Scientific and Technical Information (OSTI), août 2001. http://dx.doi.org/10.2172/786639.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
10

Doerry, Armin Walter. Autofocus correction of excessive migration in synthetic aperture radar images. Office of Scientific and Technical Information (OSTI), septembre 2004. http://dx.doi.org/10.2172/919639.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
Vous pouvez également être intéressé par les bibliographies sur le sujet « Radar imageur » pour d’autres types de sources :
Articles de revues Thèses Livres
Nous offrons des réductions sur tous les plans premium pour les auteurs dont les œuvres sont incluses dans des sélections littéraires thématiques. Contactez-nous pour obtenir un code promo unique!

Vers la bibliographie