Descripteur
Documents disponibles dans cette catégorie (247)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Full-waveform data for building roof step edge localization / Małgorzata Słota in ISPRS Journal of photogrammetry and remote sensing, vol 106 (August 2015)
[article]
Titre : Full-waveform data for building roof step edge localization Type de document : Article/Communication Auteurs : Małgorzata Słota, Auteur Année de publication : 2015 Article en page(s) : pp 129 - 144 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] détection de contours
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] forme d'onde pleine
[Termes IGN] modélisation du bâti
[Termes IGN] signal laser
[Termes IGN] toitRésumé : (auteur) Airborne laser scanning data perfectly represent flat or gently sloped areas; to date, however, accurate breakline detection is the main drawback of this technique. This issue becomes particularly important in the case of modeling buildings, where accuracy higher than the footprint size is often required. This article covers several issues related to full-waveform data registered on building step edges. First, the full-waveform data simulator was developed and presented in this paper. Second, this article provides a full description of the changes in echo amplitude, echo width and returned power caused by the presence of edges within the laser footprint. Additionally, two important properties of step edge echoes, peak shift and echo asymmetry, were noted and described. It was shown that these properties lead to incorrect echo positioning along the laser center line and can significantly reduce the edge points’ accuracy. For these reasons and because all points are aligned with the center of the beam, regardless of the actual target position within the beam footprint, we can state that step edge points require geometric corrections. This article presents a novel algorithm for the refinement of step edge points. The main distinguishing advantage of the developed algorithm is the fact that none of the additional data, such as emitted signal parameters, beam divergence, approximate edge geometry or scanning settings, are required. The proposed algorithm works only on georeferenced profiles of reflected laser energy. Another major advantage is the simplicity of the calculation, allowing for very efficient data processing. Additionally, the developed method of point correction allows for the accurate determination of points lying on edges and edge point densification. For this reason, fully automatic localization of building roof step edges based on LiDAR full-waveform data with higher accuracy than the size of the lidar footprint is feasible. Numéro de notice : A2015-724 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.05.008 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.05.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78372
in ISPRS Journal of photogrammetry and remote sensing > vol 106 (August 2015) . - pp 129 - 144[article]Assessment of high-rate GPS using a single-axis shake table / Simon Häberling in Journal of geodesy, vol 89 n° 7 (July 2015)
[article]
Titre : Assessment of high-rate GPS using a single-axis shake table Type de document : Article/Communication Auteurs : Simon Häberling, Auteur ; Markus Rothacher, Auteur ; Y. Zhang, Auteur Année de publication : 2015 Article en page(s) : pp 697 - 709 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] bruit thermique
[Termes IGN] phase
[Termes IGN] réalité de terrain
[Termes IGN] récepteur GNSS
[Termes IGN] sismographeRésumé : (auteur) The developments in GNSS receiver and antenna technologies, especially the increased sampling rate up to 100 sps, open up the possibility to measure high-rate earthquake ground motions with GNSS. In this paper we focus on the GPS errors in the frequency band above 1 Hz. The dominant error sources are mainly the carrier phase jitter caused by thermal noise and the stress error caused by the dynamics, e.g. antenna motions. To generate a large set of different motions, we used a single-axis shake table, where a GNSS antenna and a strong motion seismometer were mounted with a well-known ground truth. The generated motions were recorded with three different GNSS receivers with sampling rates up to 100 sps and different receiver baseband parameters. The baseband parameters directly dictate the carrier phase jitter and the correlations between subsequent epochs. A narrow loop filter bandwidth keeps the carrier phase jitter on a low level, but has an extreme impact on the receiver response for motions above 1 Hz. The amplitudes above 3 Hz are overestimated up to 50 % or reduced by well over half. The corresponding phase errors are between 30 and 90 degrees. Compared to the GNSS receiver response, the strong motion seismometer measurements do not show any amplitude or phase variations for the frequency range from 1 to 20 Hz. Due to the large errors for dynamic GNSS measurements, it is essential to account for the baseband parameters of the GNSS receivers if high-rate GNSS is to become a valuable tool for seismic displacement measurements above 1 Hz. Fortunately, the receiver response can be corrected by an inverse filter if the baseband parameters are known. Numéro de notice : A2015-356 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0808-2 En ligne : https://doi.org/10.1007/s00190-015-0808-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76782
in Journal of geodesy > vol 89 n° 7 (July 2015) . - pp 697 - 709[article]
[article]
Titre : Carrier-phase RF ranging Type de document : Article/Communication Auteurs : Bradley D. Farnsworth, Auteur ; E.J. Kreinar, Auteur ; David W. A. Taylor, Auteur Année de publication : 2015 Article en page(s) : pp 56 - 65 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] méthode de mesure
[Termes IGN] phase
[Termes IGN] précision des mesures
[Termes IGN] radiofréquence
[Termes IGN] télémétrie
[Termes IGN] vitesseRésumé : (auteur) In this month’s column, we take a look at a short-distance two-way ranging system using a 5.8-GHz carrier to supply not only precise and accurate distance measurements but also complementary measurements of speed. Numéro de notice : A2015-220 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://gpsworld.com/innovation-carrier-phase-rf-ranging/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76182
in GPS world > vol 26 n° 6 (June 2015) . - pp 56 - 65[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 067-2015061 RAB Revue Centre de documentation En réserve L003 Disponible Validation of canopy height profile methodology for small-footprint full-waveform airborne LiDAR data in a discontinuous canopy environment / Karolina D. Fieber in ISPRS Journal of photogrammetry and remote sensing, vol 104 (June 2015)
[article]
Titre : Validation of canopy height profile methodology for small-footprint full-waveform airborne LiDAR data in a discontinuous canopy environment Type de document : Article/Communication Auteurs : Karolina D. Fieber, Auteur ; Ian J. Davenport, Auteur ; Mihai A. Tanase, Auteur ; James M. Ferryman, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 144 - 157 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Australie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] forme d'onde pleine
[Termes IGN] hauteur des arbres
[Termes IGN] Leaf Area Index
[Termes IGN] modèle numérique de surface de la canopéeRésumé : (auteur) A Canopy Height Profile (CHP) procedure presented in Harding et al. (2001) for large footprint LiDAR data was tested in a closed canopy environment as a way of extracting vertical foliage profiles from LiDAR raw-waveform. In this study, an adaptation of this method to small-footprint data has been shown, tested and validated in an Australian sparse canopy forest at plot- and site-level. Further, the methodology itself has been enhanced by implementing a dataset-adjusted reflectance ratio calculation according to Armston et al. (2013) in the processing chain, and tested against a fixed ratio of 0.5 estimated for the laser wavelength of 1550 nm. As a by-product of the methodology, effective leaf area index (LAIe) estimates were derived and compared to hemispherical photography values. To assess the influence of LiDAR aggregation area size on the estimates in a sparse canopy environment, LiDAR CHPs and LAIes were generated by aggregating waveforms to plot- and site-level footprints (plot/site-aggregated) as well as in 5 m grids (grid-processed). LiDAR profiles were then compared to field biomass profiles generated based on field tree measurements. The correlation between field and LiDAR profiles was very high, with a mean R2 of 0.75 at plot-level and 0.86 at site-level for 55 plots and the corresponding 11 sites. Gridding had almost no impact on the correlation between LiDAR and field profiles (only marginally improvement), nor did the dataset-adjusted reflectance ratio. However, gridding and the dataset-adjusted reflectance ratio were found to improve the correlation between raw-waveform LiDAR and hemispherical photography LAIe estimates, yielding the highest correlations of 0.61 at plot-level and of 0.83 at site-level. This proved the validity of the approach and superiority of dataset-adjusted reflectance ratio of Armston et al. (2013) over a fixed ratio of 0.5 for LAIe estimation, as well as showed the adequacy of small-footprint LiDAR data for LAIe estimation in discontinuous canopy forests. Numéro de notice : A2015-702 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.03.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.03.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78338
in ISPRS Journal of photogrammetry and remote sensing > vol 104 (June 2015) . - pp 144 - 157[article]Interferometric phase image estimation via sparse coding in the complex domain / Hao Hongxing in IEEE Transactions on geoscience and remote sensing, vol 53 n° 5 (mai 2015)
[article]
Titre : Interferometric phase image estimation via sparse coding in the complex domain Type de document : Article/Communication Auteurs : Hao Hongxing, Auteur ; José M. Bioucas-Dias, Auteur ; Vladimir Katkovnik, Auteur Année de publication : 2015 Article en page(s) : pp 2587 - 2602 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] apprentissage dirigé
[Termes IGN] état de l'art
[Termes IGN] filtrage du bruit
[Termes IGN] image radar moirée
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] matrice creuse
[Termes IGN] phase
[Termes IGN] programmation par contraintes
[Termes IGN] régression
[Termes IGN] restauration d'imageRésumé : (auteur) This paper addresses interferometric phase image estimation, i.e., the estimation of phase modulo-2π images from sinusoidal 2π-periodic and noisy observations. These degradation mechanisms make interferometric phase image estimation a quite challenging problem. We tackle this challenge by reformulating the true estimation problem as a sparse regression, often termed sparse coding, in the complex domain. Following the standard procedure in patch-based image restoration, the image is partitioned into small overlapping square patches, and the vector corresponding to each patch is modeled as a sparse linear combination of vectors, termed the atoms, taken from a set called dictionary. Aiming at optimal sparse representations, and thus at optimal noise removing capabilities, the dictionary is learned from the data that it represents via matrix factorization with sparsity constraints on the code (i.e., the regression coefficients) enforced by the ℓ1 norm. The effectiveness of the new sparse-coding-based approach to interferometric phase estimation, termed the SpInPHASE, is illustrated in a series of experiments with simulated and real data where it outperforms the state-of-the-art. Numéro de notice : A2015-630 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2014.2361919 En ligne : https://doi.org/10.1109/TGRS.2014.2361919 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78118
in IEEE Transactions on geoscience and remote sensing > vol 53 n° 5 (mai 2015) . - pp 2587 - 2602[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2015051 RAB Revue Centre de documentation En réserve L003 Disponible Tsunami-wave parameter estimation using GNSS-based sea surface height measurement / Kegen Yu in IEEE Transactions on geoscience and remote sensing, vol 53 n° 5 (mai 2015)PermalinkCarrier-phase ambiguity resolution: Handling the biases for improved triple-frequency PPP convergence / Denis Laurichesse in GPS world, vol 26 n° 4 (April 2015)PermalinkWuhan ionospheric oblique-incidence sounding system and its new application in localization of ionospheric irregularities / Shu-Zhu Shi in IEEE Transactions on geoscience and remote sensing, vol 53 n° 4 (April 2015)PermalinkPositioning in challenging environments using ultra-wideband sensor networks / Zoltan Koppanyi in GPS world, vol 26 n° 3 (March 2015)PermalinkNon-invasive forest litter characterization using full-wave inversion of microwave radar data / Frédéric André in IEEE Transactions on geoscience and remote sensing, vol 53 n° 2 (February 2015)PermalinkRelating statistical characteristics of cross-polarized phase difference to speckle noise / Huimin Li in Journal of applied remote sensing, vol 9 (2015)PermalinkCompression strategies for LiDAR waveform cube / Grzegorz Jóźków in ISPRS Journal of photogrammetry and remote sensing, vol 99 (January 2015)PermalinkEmpirical waveform decomposition and radiometric calibration of a terrestrial full-waveform laser scanner / Preston J. Hartzell in IEEE Transactions on geoscience and remote sensing, vol 53 n° 1 (January 2015)PermalinkTowards an enhanced understanding of airborne LiDAR measurements of forest vegetation / Aarne Hovi (2015)PermalinkModelling electrical conductivity of soil from backscattering coefficient of microwave remotely sensed data using artificial neural network / Walaiporn Phonphan in Geocarto international, vol 29 n° 7 - 8 (November - December 2014)Permalink