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Superresolution for UAV images via adaptive multiple sparse representation and its application to 3-D reconstruction / Muhammad Haris in IEEE Transactions on geoscience and remote sensing, vol 55 n° 7 (July 2017)
[article]
Titre : Superresolution for UAV images via adaptive multiple sparse representation and its application to 3-D reconstruction Type de document : Article/Communication Auteurs : Muhammad Haris, Auteur ; Takuya Watanabe, Auteur ; Liu Fan, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 4047 - 4058 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] agriculture
[Termes IGN] carte thématique
[Termes IGN] drone
[Termes IGN] image à haute résolution
[Termes IGN] image multi sources
[Termes IGN] rapport signal sur bruit
[Termes IGN] reconstruction 3D
[Termes IGN] série temporelleRésumé : (Auteur) We propose a superresolution (SR) algorithm based on adaptive sparse representation via multiple dictionaries for images taken by unmanned aerial vehicles (UAVs). The SR attainable through the proposed algorithm can increase the precision of 3-D reconstruction from UAV images, enabling the production of high-resolution images for constructing high-frequency time series and for high-precision digital mapping in agriculture. The basic idea of the proposed method is to use a field server or ground-based camera to take training images and then construct multiple pairs of dictionaries based on selective sparse representations to reduce instability during the sparse coding process. The dictionaries are classified on the basis of the edge orientation into five clusters: 0, 45, 90, 135, and nondirection. The proposed method is expected to reduce blurring, blocking, and ringing artifacts especially in edge areas. We evaluated the proposed and previous methods using peak signal-to-noise ratio, structural similarity, feature similarity, and computation time. Our experimental results indicate that the proposed method clearly outperforms other state-of-the-art algorithms based on qualitative and quantitative analysis. In the end, we demonstrate the effectiveness of our proposed method to increase the precision of 3-D reconstruction from UAV images. Numéro de notice : A2017-491 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2017.2687419 En ligne : http://dx.doi.org/10.1109/TGRS.2017.2687419 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86420
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 7 (July 2017) . - pp 4047 - 4058[article]The extension of the parametrization of the radio source coordinates in geodetic VLBI and its impact on the time series analysis / Maria Karbon in Journal of geodesy, vol 91 n° 7 (July 2017)
[article]
Titre : The extension of the parametrization of the radio source coordinates in geodetic VLBI and its impact on the time series analysis Type de document : Article/Communication Auteurs : Maria Karbon, Auteur ; Robert Heinkelmann, Auteur ; Julian Mora-Diaz, Auteur ; Minghui Xu, Auteur ; Tobias Nilsson, Auteur ; Harald Schuh, Auteur Année de publication : 2017 Article en page(s) : pp 755 - 765 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] fonction spline
[Termes IGN] interférométrie à très grande base
[Termes IGN] paramètres d'orientation de la Terre
[Termes IGN] régression multivariée par spline adaptative
[Termes IGN] repère de référence céleste
[Termes IGN] série temporelleRésumé : (Auteur) The radio sources within the most recent celestial reference frame (CRF) catalog ICRF2 are represented by a single, time-invariant coordinate pair. The datum sources were chosen mainly according to certain statistical properties of their position time series. Yet, such statistics are not applicable unconditionally, and also ambiguous. However, ignoring systematics in the source positions of the datum sources inevitably leads to a degradation of the quality of the frame and, therefore, also of the derived quantities such as the Earth orientation parameters. One possible approach to overcome these deficiencies is to extend the parametrization of the source positions, similarly to what is done for the station positions. We decided to use the multivariate adaptive regression splines algorithm to parametrize the source coordinates. It allows a great deal of automation, by combining recursive partitioning and spline fitting in an optimal way. The algorithm finds the ideal knot positions for the splines and, thus, the best number of polynomial pieces to fit the data autonomously. With that we can correct the ICRF2 a priori coordinates for our analysis and eliminate the systematics in the position estimates. This allows us to introduce also special handling sources into the datum definition, leading to on average 30 % more sources in the datum. We find that not only the CPO can be improved by more than 10 % due to the improved geometry, but also the station positions, especially in the early years of VLBI, can benefit greatly. Numéro de notice : A2017-296 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0954-1 En ligne : http://doi.org/10.1007/s00190-016-0954-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85331
in Journal of geodesy > vol 91 n° 7 (July 2017) . - pp 755 - 765[article]GPS coordinate time series measurements in Ontario and Quebec, Canada / Hadis Samadi Alinia in Journal of geodesy, vol 91 n° 6 (June 2017)
[article]
Titre : GPS coordinate time series measurements in Ontario and Quebec, Canada Type de document : Article/Communication Auteurs : Hadis Samadi Alinia, Auteur ; Christy F. Tiampo, Auteur ; Thomas S. James, Auteur Année de publication : 2017 Article en page(s) : pp 653 - 683 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] Bernese
[Termes IGN] bruit (théorie du signal)
[Termes IGN] bruit blanc
[Termes IGN] champ de vitesse
[Termes IGN] coordonnées GPS
[Termes IGN] épaisseur de la glace
[Termes IGN] Hudson, baie d'
[Termes IGN] méthode du maximum de vraisemblance (estimation)
[Termes IGN] Ontario (Canada)
[Termes IGN] Québec (Canada)
[Termes IGN] série temporelle
[Termes IGN] station permanenteRésumé : (Auteur) New precise network solutions for continuous GPS (cGPS) stations distributed in eastern Ontario and western Québec provide constraints on the regional three-dimensional crustal velocity field. Five years of continuous observations at fourteen cGPS sites were analyzed using Bernese GPS processing software. Several different sub-networks were chosen from these stations, and the data were processed and compared to in order to select the optimal configuration to accurately estimate the vertical and horizontal station velocities and minimize the associated errors. The coordinate time series were then compared to the crustal motions from global solutions and the optimized solution is presented here. A noise analysis model with power-law and white noise, which best describes the noise characteristics of all three components, was employed for the GPS time series analysis. The linear trend, associated uncertainties, and the spectral index of the power-law noise were calculated using a maximum likelihood estimation approach. The residual horizontal velocities, after removal of rigid plate motion, have a magnitude consistent with expected glacial isostatic adjustment (GIA). The vertical velocities increase from subsidence of almost 1.9 mm/year south of the Great Lakes to uplift near Hudson Bay, where the highest rate is approximately 10.9 mm/year. The residual horizontal velocities range from approximately 0.5 mm/year, oriented south–southeastward, at the Great Lakes to nearly 1.5 mm/year directed toward the interior of Hudson Bay at stations adjacent to its shoreline. Here, the velocity uncertainties are estimated at less than 0.6 mm/year for the horizontal component and 1.1 mm/year for the vertical component. A comparison between the observed velocities and GIA model predictions, for a limited range of Earth models, shows a better fit to the observations for the Earth model with the smallest upper mantle viscosity and the largest lower mantle viscosity. However, the pattern of horizontal deformation is not well explained in the north, along Hudson Bay, suggesting that revisions to the ice thickness history are needed to improve the fit to observations. Numéro de notice : A2017-287 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0987-5 En ligne : http://doi.org/10.1007/s00190-016-0987-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85320
in Journal of geodesy > vol 91 n° 6 (June 2017) . - pp 653 - 683[article]Multivariate analysis of GPS position time series of JPL second reprocessing campaign / AliReza Amiri-Simkooei in Journal of geodesy, vol 91 n° 6 (June 2017)
[article]
Titre : Multivariate analysis of GPS position time series of JPL second reprocessing campaign Type de document : Article/Communication Auteurs : AliReza Amiri-Simkooei, Auteur ; T.H. Mohammadloo, Auteur ; Donald F. Argus, Auteur Année de publication : 2017 Article en page(s) : pp 685 - 704 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse multivariée
[Termes IGN] bruit blanc
[Termes IGN] bruit rose
[Termes IGN] campagne GPS
[Termes IGN] centre de phase
[Termes IGN] coordonnées GPS
[Termes IGN] série temporelle
[Termes IGN] terme de Chandler
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) The second reprocessing of all GPS data gathered by the Analysis Centers of IGS was conducted in late 2013 using the latest models and methodologies. Improved models of antenna phase center variations and solar radiation pressure in JPL’s reanalysis are expected to significantly reduce errors. In an earlier work, JPL estimates of position time series, termed first reprocessing campaign, were examined in terms of their spatial and temporal correlation, power spectra, and draconitic signal. Similar analyses are applied to GPS time series at 89 and 66 sites of the second reanalysis with the time span of 7 and 21 years, respectively, to study possible improvements. Our results indicate that the spatial correlations are reduced on average by a factor of 1.25. While the white and flicker noise amplitudes for all components are reduced by 29–56 %, the random walk amplitude is enlarged. The white, flicker, and random walk noise amount to rate errors of, respectively, 0.01, 0.12, and 0.09 mm/yr in the horizontal and 0.04, 0.41 and 0.3 mm/yr in the vertical. Signals reported previously, such as those with periods of 13.63, 14.76, 5.5, and 351.4 / n for n=1,2,…,8 days, are identified in multivariate spectra of both data sets. The oscillation of the draconitic signal is reduced by factors of 1.87, 1.87, and 1.68 in the east, north and up components, respectively. Two other signals with Chandlerian period and a period of 380 days can also be detected. Numéro de notice : A2017-297 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0991-9 En ligne : http://dx.doi.org/10.1007/s00190-016-0991-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85328
in Journal of geodesy > vol 91 n° 6 (June 2017) . - pp 685 - 704[article]A time-series approach to estimating soil moisture from vegetated surfaces using L-band radar backscatter / Jeffrey D. Ouellette in IEEE Transactions on geoscience and remote sensing, vol 55 n° 6 (June 2017)
[article]
Titre : A time-series approach to estimating soil moisture from vegetated surfaces using L-band radar backscatter Type de document : Article/Communication Auteurs : Jeffrey D. Ouellette, Auteur ; Joel T. Johnson, Auteur ; Anna Balenzano, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 3186 - 3193 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] couvert végétal
[Termes IGN] détection de changement
[Termes IGN] humidité du sol
[Termes IGN] image radar
[Termes IGN] radiométrie
[Termes IGN] rétrodiffusion
[Termes IGN] série temporelle
[Termes IGN] traitement d'image radarRésumé : (Auteur) Many previous studies have shown the sensitivity of radar backscatter to surface soil moisture content, particularly at L-band. Moreover, the estimation of soil moisture from radar for bare soil surfaces is well-documented, but estimation underneath a vegetation canopy remains unsolved. Vegetation significantly increases the complexity of modeling the electromagnetic scattering in the observed scene, and can even obstruct the contributions from the underlying soil surface. Existing approaches to estimating soil moisture under vegetation using radar typically rely on a forward model to describe the backscattered signal and often require that the vegetation characteristics of the observed scene be provided by an ancillary data source. However, such information may not be reliable or available during the radar overpass of the observed scene (e.g., due to cloud coverage if derived from an optical sensor). Thus, the approach described herein is an extension of a change-detection method for soil moisture estimation, which does not require ancillary vegetation information, nor does it make use of a complicated forward scattering model. Novel modifications to the original algorithm include extension to multiple polarizations and a new technique for bounding the radar-derived soil moisture product using radiometer-based soil moisture estimates. Soil moisture estimates are generated using data from the Soil Moisture Active/Passive (SMAP) satellite-borne radar and radiometer data, and are compared with up-scaled data from a selection of in situ networks used in SMAP validation activities. These results show that the new algorithm can consistently achieve rms errors less than 0.07 m3/m3 over a variety land cover types. Numéro de notice : A2017-475 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2017.2663768 En ligne : https://doi.org/10.1109/TGRS.2017.2663768 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86400
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 6 (June 2017) . - pp 3186 - 3193[article]Surface soil moisture retrieval using the L-band synthetic aperture radar onboard the Soil Moisture Active–Passive Satellite and evaluation at core validation sites / Seung-Bum Kim in IEEE Transactions on geoscience and remote sensing, vol 55 n° 4 (April 2017)PermalinkDerivation and validation of the high resolution satellite soil moisture products: a case study of the Biebrza Sentinel-1 validation sites / Jan Musiał in Geoinformation issues, Vol 8 n° 1 (2016)PermalinkStudy of the effects on GPS coordinate time series caused by higher-order ionospheric corrections calculated using the DIPOLE model / Liansheng Deng in Geodesy and Geodynamics, vol 8 n° 2 (March 2017)PermalinkSurveillance de santé structurale des ouvrages d’art incluant les systèmes de positionnement par satellites / Camille Favre in XYZ, n° 150 (mars - mai 2017)PermalinkAssessment of second- and third-order ionospheric effects on regional networks : case study in China with longer CMONOC GPS coordinate time series / Liansheng Deng in Journal of geodesy, vol 91 n° 2 (February 2017)PermalinkEffect of training class label noise on classification performances for land cover mapping with satellite image time series / Charlotte Pelletier in Remote sensing, vol 9 n° 2 (February 2017)PermalinkGRACE era variability in the Earth's oblateness: a comparison of estimates from six different sources / Thierry Meyrath in Geophysical journal international, vol 208 n° 2 (February 2017)PermalinkMass evolution of Mediterranean, Black, Red, and Caspian Seas from GRACE and altimetry : accuracy assessment and solution calibration / B. D. Loomis in Journal of geodesy, vol 91 n° 2 (February 2017)PermalinkA network-based enhanced spectral diversity approach for TOPS time-series analysis / Heresh Fattahi in IEEE Transactions on geoscience and remote sensing, vol 55 n° 2 (February 2017)PermalinkOn the consistency of the current conventional EOP series and the celestial and terrestrial reference frames / Santiago Belda in Journal of geodesy, vol 91 n° 2 (February 2017)Permalink