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Modified residual method for the estimation of noise in hyperspectral images / Asad Mahmood in IEEE Transactions on geoscience and remote sensing, vol 55 n° 3 (March 2017)
[article]
Titre : Modified residual method for the estimation of noise in hyperspectral images Type de document : Article/Communication Auteurs : Asad Mahmood, Auteur ; Amandine Robin, Auteur ; Michael Sears, Auteur Année de publication : 2017 Article en page(s) : pp 1451 - 1460 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] bande spectrale
[Termes IGN] bruit blanc
[Termes IGN] corrélation
[Termes IGN] corrélation automatique de points homologues
[Termes IGN] filtrage du bruit
[Termes IGN] image hyperspectrale
[Termes IGN] matrice de covariance
[Termes IGN] résiduRésumé : (Auteur) Many hyperspectral image processing algorithms (e.g., detection, classification, endmember extraction, and so on) are generally designed with the assumption of no spectral or spatial correlation in noise. However, previous studies have shown the presence of nonnegligible correlation between the noise samples in different spectral bands, especially between noises in adjacent bands, and that most of the well-known intrinsic dimension estimation algorithms give poor estimates in the presence of correlated noise. Thus, there is a need to tackle the specific case of spectrally correlated noise for noise estimation. We show, in this paper, that the commonly employed hyperspectral noise estimation algorithm based on regression residuals can be significantly affected by spectrally correlated noise and we suggest a modified approach that proves to be robust to noise correlation. Furthermore, the proposed method improves the noise variance estimates in comparison to the classic residual method even for the case of uncorrelated noise. Simulation results show that the estimation error is reduced at times by a factor of 5 when there is high spectral correlation in the noise. Our proposed per-pixel noise estimator requires an estimate of the noise covariance matrix, and for this, we also propose a method to estimate the noise covariance matrix. Simulation results demonstrate that the per-pixel noise estimates obtained via the use of estimated noise statistics are almost as good as those obtained via use of the true statistics. Numéro de notice : A2017-155 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2624505 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2624505 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84690
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 3 (March 2017) . - pp 1451 - 1460[article]Mass 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)
[article]
Titre : Mass evolution of Mediterranean, Black, Red, and Caspian Seas from GRACE and altimetry : accuracy assessment and solution calibration Type de document : Article/Communication Auteurs : B. D. Loomis, Auteur ; Scott B. Luthcke, Auteur Année de publication : 2017 Article en page(s) : pp 195 - 206 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Caspienne, mer
[Termes IGN] données altimétriques
[Termes IGN] données GRACE
[Termes IGN] étalonnage des données
[Termes IGN] masse d'eau
[Termes IGN] Méditerranée, mer
[Termes IGN] Noire, mer
[Termes IGN] résidu
[Termes IGN] Rouge, mer
[Termes IGN] série temporelleRésumé : (Auteur) We present new measurements of mass evolution for the Mediterranean, Black, Red, and Caspian Seas as determined by the NASA Goddard Space Flight Center (GSFC) GRACE time-variable global gravity mascon solutions. These new solutions are compared to sea surface altimetry measurements of sea level anomalies with steric corrections applied. To assess their accuracy, the GRACE- and altimetry-derived solutions are applied to the set of forward models used by GSFC for processing the GRACE Level-1B datasets, with the resulting inter-satellite range-acceleration residuals providing a useful metric for analyzing solution quality. We also present a differential correction strategy to calibrate the time series of mass change for each of the seas by establishing the strong linear relationship between differences in the forward modeled mass and the corresponding range-acceleration residuals between the two solutions. These calibrated time series of mass change are directly determined from the range-acceleration residuals, effectively providing regionally-tuned GRACE solutions without the need to form and invert normal equations. Finally, the calibrated GRACE time series are discussed and combined with the steric-corrected sea level anomalies to provide new measurements of the unmodeled steric variability for each of the seas over the span of the GRACE observation record. We apply ensemble empirical mode decomposition (EEMD) to adaptively sort the mass and steric components of sea level anomalies into seasonal, non-seasonal, and long-term temporal scales. Numéro de notice : A2017-063 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0952-3 En ligne : http://dx.doi.org/10.1007/s00190-016-0952-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84277
in Journal of geodesy > vol 91 n° 2 (February 2017) . - pp 195 - 206[article]On 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)
[article]
Titre : On the consistency of the current conventional EOP series and the celestial and terrestrial reference frames Type de document : Article/Communication Auteurs : Santiago Belda, Auteur ; Robert Heinkelmann, Auteur ; José M. Ferrándiz,, Auteur ; Tobias Nilsson, Auteur Année de publication : 2017 Article en page(s) : pp 135 - 149 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] erreur systématique
[Termes IGN] interférométrie à très grande base
[Termes IGN] International Earth Rotation Service
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] orientation de la Terre
[Termes IGN] repère de référence céleste
[Termes IGN] rotation de la Terre
[Termes IGN] série temporelleRésumé : (Auteur) Precise transformation between the celestial reference frames (CRF) and terrestrial reference frames (TRF) is needed for many purposes in Earth and space sciences. According to the Global Geodetic Observing System (GGOS) recommendations, the accuracy of positions and stability of reference frames should reach 1 mm and 0.1 mm year−1, and thus, the Earth Orientation Parameters (EOP) should be estimated with similar accuracy. Different realizations of TRFs, based on the combination of solutions from four different space geodetic techniques, and CRFs, based on a single technique only (VLBI, Very Long Baseline Interferometry), might cause a slow degradation of the consistency among EOP, CRFs, and TRFs (e.g., because of differences in geometry, orientation and scale) and a misalignment of the current conventional EOP series, IERS 08 C04. We empirically assess the consistency among the conventional reference frames and EOP by analyzing the record of VLBI sessions since 1990 with varied settings to reflect the impact of changing frames or other processing strategies on the EOP estimates. Our tests show that the EOP estimates are insensitive to CRF changes, but sensitive to TRF variations and unmodeled geophysical signals at the GGOS level. The differences between the conventional IERS 08 C04 and other EOP series computed with distinct TRF settings exhibit biases and even non-negligible trends in the cases where no differential rotations should appear, e.g., a drift of about 20 μas year−1in ypol when the VLBI-only frame VTRF2008 is used. Likewise, different strategies on station position modeling originate scatters larger than 150 μas in the terrestrial pole coordinates. Numéro de notice : A2017-061 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0944-3 En ligne : http://dx.doi.org/10.1007/s00190-016-0944-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84273
in Journal of geodesy > vol 91 n° 2 (February 2017) . - pp 135 - 149[article]Ambiguity resolved precise point positioning with GPS and BeiDou / Pan Li in Journal of geodesy, vol 91 n° 1 (January 2017)
[article]
Titre : Ambiguity resolved precise point positioning with GPS and BeiDou Type de document : Article/Communication Auteurs : Pan Li, Auteur ; Xiaohong Zhang, Auteur ; Fei Guo, Auteur Année de publication : 2017 Article en page(s) : pp 25 - 40 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] combinaison au niveau des observations
[Termes IGN] erreur systématique
[Termes IGN] fractional cycle bias
[Termes IGN] positionnement par BeiDou
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïté
[Termes IGN] simple différenceRésumé : (Auteur) This paper focuses on the contribution of the global positioning system (GPS) and BeiDou navigation satellite system (BDS) observations to precise point positioning (PPP) ambiguity resolution (AR). A GPS + BDS fractional cycle bias (FCB) estimation method and a PPP AR model were developed using integrated GPS and BDS observations. For FCB estimation, the GPS + BDS combined PPP float solutions of the globally distributed IGS MGEX were first performed. When integrating GPS observations, the BDS ambiguities can be precisely estimated with less than four tracked BDS satellites. The FCBs of both GPS and BDS satellites can then be estimated from these precise ambiguities. For the GPS + BDS combined AR, one GPS and one BDS IGSO or MEO satellite were first chosen as the reference satellite for GPS and BDS, respectively, to form inner-system single-differenced ambiguities. The single-differenced GPS and BDS ambiguities were then fused by partial ambiguity resolution to increase the possibility of fixing a subset of decorrelated ambiguities with high confidence. To verify the correctness of the FCB estimation and the effectiveness of the GPS + BDS PPP AR, data recorded from about 75 IGS MGEX stations during the period of DOY 123-151 (May 3 to May 31) in 2015 were used for validation. Data were processed with three strategies: BDS-only AR, GPS-only AR and GPS + BDS AR. Numerous experimental results show that the time to first fix (TTFF) is longer than 6 h for the BDS AR in general and that the fixing rate is usually less than 35 % for both static and kinematic PPP. An average TTFF of 21.7 min and 33.6 min together with a fixing rate of 98.6 and 97.0 % in static and kinematic PPP, respectively, can be achieved for GPS-only ambiguity fixing. For the combined GPS + BDS AR, the average TTFF can be shortened to 16.9 min and 24.6 min and the fixing rate can be increased to 99.5 and 99.0 % in static and kinematic PPP, respectively. Results also show that GPS + BDS PPP AR outperforms single-system PPP AR in terms of convergence time and position accuracy. Numéro de notice : A2017-059 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0935-4 En ligne : http://dx.doi.org/10.1007/s00190-016-0935-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84267
in Journal of geodesy > vol 91 n° 1 (January 2017) . - pp 25 - 40[article]Exterior orientation revisited : a robust method based on lq -norm / Jiayuan Li in Photogrammetric Engineering & Remote Sensing, PERS, vol 83 n° 1 (January 2017)
[article]
Titre : Exterior orientation revisited : a robust method based on lq -norm Type de document : Article/Communication Auteurs : Jiayuan Li, Auteur ; Qingwu Hu, Auteur ; Ruofei Zhong, Auteur ; Mingyao Ai, Auteur Année de publication : 2017 Article en page(s) : pp 47 - 56 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] caméra numérique
[Termes IGN] équation de Lagrange
[Termes IGN] orientation du capteur
[Termes IGN] orientation externe
[Termes IGN] valeur aberranteRésumé : (Auteur) Camera exterior orientation is essential in many photogrammetry and computer vision applications, including 3D reconstruction, digital orthophoto map (DOM) generation, and localization. In this paper, we propose a new formulation of exterior orientation that is robust against gross errors (outliers). Different from classic optimization methods whose cost function is based on the l q -norm of residuals, we use l q -norm (0 Numéro de notice : A2017-037 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.83.1.47 En ligne : https://doi.org/10.14358/PERS.83.1.47 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84092
in Photogrammetric Engineering & Remote Sensing, PERS > vol 83 n° 1 (January 2017) . - pp 47 - 56[article]GPS/BDS short-term ISB modelling and prediction / Nan Jiang in GPS solutions, vol 21 n° 1 (January 2017)PermalinkNew iterative learning strategy to improve classification systems by using outlier detection techniques / Charlotte Pelletier (2017)PermalinkIs the Jason-2 DORIS oscillator also affected by the South Atlantic Anomaly? / Pascal Willis in Advances in space research, vol 58 n° 12 (15 December 2016)PermalinkAn attempt to determine the effect of increase of observation correlations on detectability and identifiability of a single gross error / Witold Proszynski in Geodesy and cartography, vol 65 n° 2 (December 2016)PermalinkAssessment of the accuracy of global geodetic satellite laser ranging observations and estimated impact on ITRF scale: estimation of systematic errors in LAGEOS observations 1993–2014 / Graham Appleby in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkA drift line bias estimator: ARMA-based filter or calibration method, and its application in BDS/GPS-based attitude determination / Zhang Liang in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkImproved ambiguity resolution for URTK with dynamic atmosphere constraints / Weiming Tang in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkPrecise point positioning model using triple GNSS constellations: GPS, Galileo and BeiDou / Akram Afifi in Journal of applied geodesy, vol 10 n° 4 (December 2016)PermalinkRigorous strip adjustment of UAV-based laserscanning data including time-dependent correction of trajectory errors / Philipp Glira in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 12 (December 2016)PermalinkAn approach for estimating time-variable rates from geodetic time series / Olga Didova in Journal of geodesy, vol 90 n° 11 (November 2016)Permalink