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contenu dans Proceedings, Commission 3, XXII ISPRS Congress, 25 August – 01 September 2012, Melbourne, Australia / M. Shortis (2012)
Titre : Reconstruction of sky illumination domes from ground-based panoramas Type de document : Article/Communication Auteurs : Fabien Coubard , Auteur ; Lâmân Lelégard , Auteur ; Mathieu Brédif , Auteur ; Nicolas Paparoditis , Auteur ; Xavier Briottet , Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2012 Collection : International Archives of Photogrammetry and Remote Sensing, ISSN 0252-8231 num. 39-B3 Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Archives Commission 3 Importance : pp 269 - 274 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] correction radiométrique
[Termes IGN] éclairement lumineux
[Termes IGN] image terrestre
[Termes IGN] panorama sphérique
[Termes IGN] radiance
[Termes IGN] scène urbaineRésumé : (auteur) The knowledge of the sky illumination is important for radiometric corrections and for computer graphics applications such as relighting or augmented reality. We propose an approach to compute environment maps, representing the sky radiance, from a set of ground-based images acquired by a panoramic acquisition system, for instance a mobile-mapping system. These images can be affected by important radiometric artifacts, such as bloom or overexposure. A Perez radiance model is estimated with the blue sky pixels of the images, and used to compute additive corrections in order to reduce these radiometric artifacts. The sky pixels are then aggregated in an environment map, which still suffers from discontinuities on stitching edges. The influence of the quality of estimated sky radiance on the simulated light signal is measured quantitatively on a simple synthetic urban scene; in our case, the maximal error for the total sensor radiance is about 10%. Numéro de notice : C2012-015 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.5194/isprsarchives-XXXIX-B3-23-2012 En ligne : http://dx.doi.org/10.5194/isprsarchives-XXXIX-B3-269-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94278 Ultrawideband gated step frequency Ground-Penetrating Radar / M. Oyan in IEEE Transactions on geoscience and remote sensing, vol 50 n° 1 (January 2012)
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Titre : Ultrawideband gated step frequency Ground-Penetrating Radar Type de document : Article/Communication Auteurs : M. Oyan, Auteur ; S.E. Hamran, Auteur ; L. Hanssen, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 212 - 220 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] bande spectrale
[Termes IGN] capteur spatial
[Termes IGN] modulation de fréquence
[Termes IGN] prototype
[Termes IGN] radar pénétrant GPR
[Termes IGN] SvalbardRésumé : (Auteur) We describe a prototype ultrawideband radar. We show how the system was designed and how the hardware was developed for the radar prototype. Waveform generation, radar parameters, and signal processing for the stepped frequency waveform are discussed. The radar operates from 500 MHz to 3 GHz with a nominal resolution of 6 cm in air. The advantage of the stepped frequency approach over an impulse radar is better matching between the transmitted waveform and the receiver. We use range gating to improve the system dynamic range. The advantages are illustrated with laboratory measurements and field measurements from glacial ice and permafrost in Svalbard, showing penetration depths of 11 m. Antennas which do not require contact with the ground were developed and used in the experiments. Numéro de notice : A2012-034 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2168532 Date de publication en ligne : 22/08/2011 En ligne : https://doi.org/10.1109/TGRS.2011.2168532 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31482
in IEEE Transactions on geoscience and remote sensing > vol 50 n° 1 (January 2012) . - pp 212 - 220[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2012011 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : Water vapor tomography using global navigation satellites systems Type de document : Thèse/HDR Auteurs : Donat Perler, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2012 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 84 Importance : 188 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-30-7 Note générale : Bibliographie
Doctoral ThesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] atmosphère terrestre
[Termes IGN] données GNSS
[Termes IGN] données météorologiques
[Termes IGN] modélisation spatiale
[Termes IGN] positionnement par GNSS
[Termes IGN] rayonnement électromagnétique
[Termes IGN] temps réel
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie par GPS
[Termes IGN] vapeur d'eauIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (Auteur) Water vapor plays an important role in the atmosphere. It is involved in many atmospheric processes and is a major contributor to the atmospheric energy budget and as such is a key quantity in numerical weather prediction (NWP) models. In recent years, NWP models gain in importance in hazard mitigation. But to provide precise quantitative forecasts, especially with respect to precipitation, we need accurate knowledge of the water vapor distribution in the atmosphere. Ground-based Global Navigation Satellite System (GNSS) tomography is a technique which can provide highly resolved and accurate water vapor profiles in space and time.
The main objective of this thesis is to develop new tomographic algorithms which fulfill the requirements to assimilate refractivity measurements derived from GNSS into NWP models. A new tomography software called AWATOS 2 has been implemented. It is an assimilation system for point and integrated refractivity measurements. The tomographic model in AWATOS 2 is formulated as a Kalman filter and different voxel parameterizations are provided. The new trilinear and spline-based parameterizations allow a more accurate representation of the refractivity field without considerably increasing the number of unknowns. Advantages of these new parameterizations are a) more accurate results, b) point observations need not to be interpolated to the voxel centers and c) the tomographic solutions are at least C0-continuous in space. The stochastic prediction model implemented in AWATOS 2 relies on in-situ measurements and NWP model data. The prediction model is evaluated and adjusted with respect to data from the high-resolution NWP model COSMO-2 and from balloon soundings in Europe. In addition, AWATOS 2 provides a sophisticated simulation framework to carry out synthetic tests based on simple refractivity fields and on NWP model data. The algorithms of AWATOS 2 are assessed with synthetic tests and with real data in a longterm study using one year of data. The synthetic tests have confirmed the theoretical properties of the model such as a bias-free solution in case of bias-free input data, fast convergence rates, and the capability to resolve vertical structures in the wet refractivity field. In the long-term study, a root-mean-square (RMS) error of 3.0 ppm (0.4 gm3 absolute humidity) is achieved with respect to the NWP model COSMO-7. The investigations have shown that the newly introduced voxel parameterizations lead to significantly more accurate results than the classical constant parameterization.
The improvements are about 15% with respect to balloon soundings and 5% with respect to NWP analysis data. The performance of the trilinear and spline-based parameterizations are similar. Further investigations have revealed the importance of a bias correction model. A newly developed bias correction model has decreased the RMS error with respect to the NWP model analysis from 4.9 ppm (0.7 gm3) to 3.0 ppm (0.4 gm3) using the spline parameterization. For the other parameterizations, the improvements are significantly smaller. The systematic differences corrected here are mainly caused by a) systematic differences between GPS tropospheric path delays and the NWP model data and b) by discretization errors. Another error source is related to the departure of the NWP model’s topography from the true one which can amount to several hundred meters in alpine areas. Investigations have shown that processes near the Earth’s surface have a strong impact on the wet refractivity. Therefore, differences between the true topography and that of the NWP model can cause substantial errors. This topic has to be addressed if GNSS observations are assimilated into NWP models in complex terrain. Considerable progress has been made in the field of low-cost GNSS receivers in recent years allowing to build dense networks at low costs. Furthermore, the existing GNSSs are improved and new ones are being launched. These developments offer new possibilities in GNSS tomography. With error analyses, the potential of such improvements for GNSS tomography have been investigated The use of GPS together with Galileo has the potential to improve the formal accuracy of the GNSS tomography by 10-15% compared to a GPS-only solution. In Switzerland, equipping the SwissMetNet with GNSS receivers would increase the number of GNSS stations from 31 to 91. This would improve the formal accuracy of the tomographic solution by about 20-25%. The investigations have shown that the improvements obtained by a more dense network and additional GNSSs are cumulative. Placing the stations on different altitudes and choosing locations with good satellite visibility are important to achieve accurate results and should be considered in the design of GNSS networks.
All investigations have demonstrated that accurate 4D distributions of the wet refractivity in the troposphere can be estimated with GNSS tomography. The work has also revealed the possibilities and limitations of GNSS tomography in view of the assimilation into NWP models and proposes solution strategies to overcome the limitations.Note de contenu : 1 Introduction
1.1 Significance of tropospheric water vapor measurements
1.2 A short review of the research in GNSS tomography
1.3 Objectives and structure of the thesis
2 Introduction to the propagation of radio waves in the atmosphere
2.1 Propagation of radio waves in the atmosphere
2.2 Modeling the path delay
3 GNSS tomography with the software package AWATOS 2
3.1 Overview of AWATOS 2
3.2 Preprocessing of GNSS double difference delays
3.3 Discretization of the refractivity field and parameterization
3.4 Modeling the refractivity field with the Kalman filter approach
3.5 Simulation capabilities in AWATOS 2
4 Overview of the data sets
4.1 GPS data
4.2 Balloon soundings
4.3 Synoptic network SwissMetNet
4.4 Numerical weather prediction model COSMO
5 Description of the wet refractivity field
5.1 Tempo-spatial variation of the wet refractivity field
5.2 Discretization Error
5.3 Representation of the discretization error .
5.4 Investigations of the process noise using a random walk model
5.5 Conclusions
6 Comparison of balloon sounding data and GNSS-derived zenith path delays
6.1 Error budget of meteorological sensors
6.2 Intercomparison between zenith path delays of different sources
6.3 Conclusions
7 Potential of new GNSSs and dense networks in view of GNSS tomography
7.1 Configurations
7.2 Methods
7.3 Results and discussion
7.4 Conclusions
8 Simulation-based evaluation of the new tomographic algorithms
8.1 Theoretical considerations of the resolvability of vertical structures
8.2 Experiments with simulated data
8.3 Conclusions
9 Evaluation of the GPS tomography with a long-term study
9.1 Configuration and evaluation methods
9.2 Results and discussion
9.3 Bias correction model and its evaluation
9.4 Conclusions
10 Conclusions
11 OutlookNuméro de notice : 15546 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-006875504 En ligne : http://dx.doi.org/10.3929/ethz-a-006875504 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62758 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15546-01 30.84 Livre Centre de documentation Géodésie Disponible Potential of an ultraviolet, medium-footprint lidar prototype for retrieving forest structure / Tristan Allouis in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 supplement (December 2011)
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Titre : Potential of an ultraviolet, medium-footprint lidar prototype for retrieving forest structure Type de document : Article/Communication Auteurs : Tristan Allouis, Auteur ; Sylvie Durrieu, Auteur ; Patrick Chazette, Auteur ; J. Bailly, Auteur ; et al., Auteur ; Cédric Vega , Auteur Année de publication : 2011 Article en page(s) : pp 92 - 102 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Aquitaine
[Termes IGN] atténuation du signal
[Termes IGN] correction du signal
[Termes IGN] données lidar
[Termes IGN] empreinte
[Termes IGN] forêt tempérée
[Termes IGN] géostatistique
[Termes IGN] hauteur des arbres
[Termes IGN] instrument aéroporté
[Termes IGN] Landes (40)
[Termes IGN] Pinophyta
[Termes IGN] rayonnement ultraviolet
[Termes IGN] surveillance forestièreRésumé : (Auteur) The aim of the paper is to carry on methodological development for retrieving forest parameters from medium-footprint lidar signals and for assessing the performance of different sampling strategies. The 2.4 m footprint lidar prototype (a profiler instrument using an ultraviolet laser) was flown above two different maritime pine stands: a young plantation (10 years old) and a mature, semi-natural stand (55 years old), both in the Landes forest, France. The vertical distribution of lidar measurements was studied for retrieving forest height parameters (mean total height, mean crown height and top height). The processing algorithm was based on an aggregation of successive signals followed by the correction of the signal attenuation along the travel through the vegetation. The performance of different sampling strategies was assessed by comparing the results for the full dataset (several fight lines over the stands) and for only a data subset (one flight line). In addition, the horizontal distribution of height measurements was studied for identifying the planting pattern of the stands and assessing the tree spacing of the semi-natural parcel, using geostatistics. We obtained a submetric estimation error (lidar – reference) of 0.2 m on the mean total height in the young stand (-0.7 m in the mature stand), a bias of -0.3 m (-0.3 m) on the mean crown height measurement and of 0.6 m (-1.0 m) on the top height. The planting pattern was also successfully identified, and the distance between trees was assessed in agreement with ground measurements. Having demonstrated its ability to assess forest structure, even with a unique flight line, the lidar prototype seems to be a valuable sensor for performing fast forest inventory at regional scale. In addition, this sensor opens the way to the development of bi-functional lidar for both atmosphere and vegetation remote sensing. Numéro de notice : A2011-522 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2011.08.007 En ligne : https://doi.org/10.1016/j.isprsjprs.2011.08.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31416
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 6 supplement (December 2011) . - pp 92 - 102[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2011071 SL Revue Centre de documentation Revues en salle Disponible Testing a near-infrared Lidar mounted with a large incidence angle to monitor the water level of turbid reservoirs / S. Tamari in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 supplement (December 2011)
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Titre : Testing a near-infrared Lidar mounted with a large incidence angle to monitor the water level of turbid reservoirs Type de document : Article/Communication Auteurs : S. Tamari, Auteur ; J. Mory, Auteur ; V. Guerrero-Meza, Auteur Année de publication : 2011 Article en page(s) : pp 85 - 91 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] angle d'incidence
[Termes IGN] coefficient de rétrodiffusion
[Termes IGN] données lidar
[Termes IGN] niveau de l'eau
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] rétrodiffusionRésumé : (Auteur) It is sometimes difficult to monitor the water level of reservoirs with a sloping bank – such as many lakes and earth-dam embankment – using terrestrial techniques or airborne instruments. A proposed alternative is a new technique using a terrestrial near-infrared Lidar mounted with a large incidence angle (at least between 40° and 70°). This technique assumes that the Lidar can detect the (sub-)surface of a water body provided that it contains enough suspended particles to backscatter the light emitted by the instrument to its detector. Tests performed with a commercial Lidar show that the technique can be used to estimate the water level of a reservoir with moderate accuracy (within 10.05 m [p = 0.95]) when the water is very turbid (Secchi depth Numéro de notice : A2011-521 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2011.01.009 En ligne : https://doi.org/10.1016/j.isprsjprs.2011.01.009 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31415
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 6 supplement (December 2011) . - pp 85 - 91[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2011071 SL Revue Centre de documentation Revues en salle Disponible Validation of international reference ionosphere models using in situ measurements from GRACE K-band ranging system and CHAMP planar Langmuir probe / C. Lee in Journal of geodesy, vol 85 n° 12 (December 2011)PermalinkCartographie des sols hydromorphes de la région des lacs (Côte d'Ivoire) par l'approche du spectral angle mapper (SAM) / G. Zro Bi in Revue Française de Photogrammétrie et de Télédétection, n° 195 (Novembre 2011)PermalinkAn approach to the radiometric aerotriangulation of photogrammetric images / David Hernandez-Lopez in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 (November 2011)PermalinkImproving the assessment of ICESat water altimetry accuracy accounting for autocorrelation / Hani Abdallah in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 (November 2011)PermalinkSVM-based unmixing-to-classification conversion for hyperspectral abundance quantification / F. Mianji in IEEE Transactions on geoscience and remote sensing, vol 49 n° 11 Tome 1 (November 2011)PermalinkAccuracy assessment of the GPS-TEC calibration constants by means of a simulation technique / Jacques Conte in Journal of geodesy, vol 85 n° 10 (October 2011)PermalinkGeolocation and stereo height estimation using TerraSAR-X spotlight image data / K. Eldhuset in IEEE Transactions on geoscience and remote sensing, vol 49 n° 10 Tome 1 (October 2011)PermalinkPerformance requirements for ionospheric correction of low-frequency SAR data / J. Meyer in IEEE Transactions on geoscience and remote sensing, vol 49 n° 10 Tome 1 (October 2011)PermalinkRadar backscatter mapping using TerraSAR-X / P. Rizzoli in IEEE Transactions on geoscience and remote sensing, vol 49 n° 10 Tome 1 (October 2011)Permalinkvol 49 n° 9 - September 2011 - 11th specialist meeting on Microwave Radiometry and remote sensing applications (MICRORAD2010) (Bulletin de IEEE Transactions on geoscience and remote sensing) / Geoscience and remote sensing societyPermalink