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Seamline detection in colour orthoimage mosaicking by use of twin snakes / M. Kerschner in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 1 (May - June 2001)
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Titre : Seamline detection in colour orthoimage mosaicking by use of twin snakes Type de document : Article/Communication Auteurs : M. Kerschner, Auteur Année de publication : 2001 Article en page(s) : pp 53 - 64 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] détection de contours
[Termes IGN] mosaïque d'images
[Termes IGN] orthoimage
[Termes IGN] orthoimage couleur
[Termes IGN] teinteRésumé : (Auteur) In the last step of the mosaic production chain, neighbouring and partly overlapping orthoimages of a scene are merged to one mosaic. This should be done in a way that the transition from one to another orthoimage cannot be seen. The production line of orthoimages consists of several steps, each of which can introduce a different appearance regarding geometry, radiometry and spectral properties to the resulting orthoimage. For mosaicking adjacent orthoimages, a path of lowest difference in a combination of criteria is searched in the overlap area of these images. The seamline is chosen along this path of maximum similarity. In this paper, criteria for such an optimal seamline in colour orthoimages are elaborated. The main requirements are on one hand high colour similarity of the images (mainly in hue and intensity), and on the other hand high texture similarity (in orientation and magnitude of image gradients). The specified criteria are formulated in the energy function of snakes. A snake is an active contour which moves through an image and changes its shape until a minimum of its energy function is found. We use two snakes that attract one another (twin snakes). In a hierarchical strategy, a proper seamline is delineated fully automatically. The potential of the method is shown with an example. Copyright ISPRS Numéro de notice : A2001-220 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(01)00033-8 En ligne : https://doi.org/10.1016/S0924-2716(01)00033-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21914
in ISPRS Journal of photogrammetry and remote sensing > vol 56 n° 1 (May - June 2001) . - pp 53 - 64[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-01021 SL Revue Centre de documentation Revues en salle Disponible Modifications of Tanaka's illuminated contour method / Patrick Kennelly in Cartography and Geographic Information Science, vol 28 n° 2 (April 2001)
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Titre : Modifications of Tanaka's illuminated contour method Type de document : Article/Communication Auteurs : Patrick Kennelly, Auteur ; A.J. Kimerling, Auteur Année de publication : 2001 Article en page(s) : pp 111 - 123 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique
[Termes IGN] carte des pentes
[Termes IGN] contour
[Termes IGN] éclairement lumineux
[Termes IGN] niveau de gris (image)
[Termes IGN] représentation du relief
[Termes IGN] visualisation cartographiqueRésumé : (Auteur) Visualization of topography can be greatly facilitated by the illuminated contour method. This method, popularized in a hand-drafted map byTanaka, uses a gray background with black and white contours. A direction of illumination is assumed, and white contours represent illuminated topography, while black contours represent non-illuminated or shaded areas. Additionally, thickness of contours varies with the cosine of the angle between the azimuth of maximum slope (i.e., aspect) and the azimuth of illumination. We modified Tanaka's method by basing thickness of contour lines on twice the cosine of the angle between the surface normal and the illumination vector. The cosine of this angle is most commonly used in analytical bill shading. In addition, we present maps with changes in other visual variables and offer our evaluations. Lines with gray tones instead of black and white lines do not improve the illumination effect. We believe variations in the colors of contours and background with elevation can visually enforce information regarding topography. Our use of colors for aspect and variations in the width of contours for slope adds information to the map but does not assist with visualization of topography. Numéro de notice : A2001-100 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304001782173709 En ligne : https://doi.org/10.1559/152304001782173709 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21800
in Cartography and Geographic Information Science > vol 28 n° 2 (April 2001) . - pp 111 - 123[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-01021 RAB Revue Centre de documentation En réserve L003 Disponible An interactive approach to analytical relief shading / J. Jenny in Cartographica, vol 38 n° 1 - 2 (March 2001)
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Titre : An interactive approach to analytical relief shading Type de document : Article/Communication Auteurs : J. Jenny, Auteur Année de publication : 2001 Article en page(s) : pp 67 - 75 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique
[Termes IGN] carte interactive
[Termes IGN] cartographie thématique
[Termes IGN] estompage automatique
[Termes IGN] niveau de gris (image)
[Termes IGN] rayonnement lumineux
[Termes IGN] représentation du relief
[Termes IGN] visualisation cartographiqueRésumé : (Auteur) L'estompage est un moyen de visualisation du relief en cartographie qui peut être produit de manière traditionnelle (dessin manuel) ou par des calculs informatiques. Les logiciels d'estompage existants actuellement ne permettent pas d'adaptations locales de direction de la lumière. La simulation de perspective aérienne ou des modifications manuelles y sont également impossibles. Pour combler ces lacunes, un programme d'estompage assisté par ordinateur à été développé. Il permet à l'utilisateur d'adapter localement les estompages grâce à un contrôle interactif de l'intégralité du processus. Les valeurs de gris du relief y sont définies à partir d'une combinaison de deux méthodes : l'estompage des pentes raides est calculé à partir de l'orientation du relief, et l'estompage des surfaces plus planes est calculé à partir de la réflexion diffuse de la lumière. Par ailleurs, un nouvel algorithme pour la simulation d'effets de perspective aérienne à été utilisé afin d'améliorer ces estompages. Contrairement à d'autres programmes du même type, il s'est avéré que les cartographes ayant une solide expérience manuelle des techniques d'estompage, peuvent ici facilement transférer leurs connaissances au monde digital. Numéro de notice : A2003-220 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3138/F722-0825-3142-HW05 En ligne : https://doi.org/10.3138/F722-0825-3142-HW05 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22516
in Cartographica > vol 38 n° 1 - 2 (March 2001) . - pp 67 - 75[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 031-01011 RAB Revue Centre de documentation En réserve L003 Disponible Study of external path delay correction techniques for high accuracy height determination with GPS / Olivier Bock in Physics and chemistry of the Earth, Part A: Solid Earth and Geodesy, vol 26 n° 3 ([01/03/2001])
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Titre : Study of external path delay correction techniques for high accuracy height determination with GPS Type de document : Article/Communication Auteurs : Olivier Bock , Auteur ; Jérôme Tarniewicz
, Auteur ; Christian Thom
, Auteur ; Jacques Pelon, Auteur ; Michel Kasser
, Auteur
Année de publication : 2001 Article en page(s) : pp 165 - 171 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] lidar Raman
[Termes IGN] précision du positionnement
[Termes IGN] résidu
[Termes IGN] retard ionosphèrique
[Termes IGN] retard troposphérique
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement de données GNSSRésumé : (auteur) For specific applications such as permanent GPS network calibration and national leveling network surveying, a vertical accuracy of ∼1 mm for observing durations of a few hours to a few days at maximum in 10–100-km baselines would be required. To achieve a 1-mm accuracy in height determinations with differential-GPS measurements, path delay must be corrected with an accuracy of ∼0.3 mm. This level of accuracy is not achievable with standard GPS data analysis procedures. External correction from a water vapor remote sensing technique is therefore necessary. Microwave radiometers, which have been most extensively used for this purpose, solar spectrometers, DIAL and Raman lidars are considered in this paper. The principle and performance of these techniques is reviewed in the context of wet path delay retrieving. Namely, we evaluate the errors arising during the conversion of raw measurements to wet path delay, using retrieval coefficients or standard profiles. It is shown that changes in temperature profiles can produce errors of up to 1 cm in wet path delay with microwave radiometers. Similarly, mismodeled temperature profiles can produce errors of 2–3 mm in wet path delay with DIAL and Raman lidars. Raman lidar offers the possibility to retrieve the temperature profile from total air density. Assuming that absolute concentrations of water vapor and dry gases can be retrieved, the accuracy would be unbiased. In addition, Raman lidar would also allow for the correction of hydrostatic path delay without requiring the use of mapping functions. This might reduce the residual errors due to horizontal pressure and temperature gradients. This technique will therefore be investigated in more details in a future study. Numéro de notice : A2001-261 Affiliation des auteurs : LOEMI+Ext (1985-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S1464-1895(01)00041-2 Date de publication en ligne : 07/05/2001 En ligne : https://doi.org/10.1016/S1464-1895(01)00041-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103207
in Physics and chemistry of the Earth, Part A: Solid Earth and Geodesy > vol 26 n° 3 [01/03/2001] . - pp 165 - 171[article]Analysis of refraction influences in geodesy using image processing and turbulence models / Philipp Flach (2001)
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Titre : Analysis of refraction influences in geodesy using image processing and turbulence models Type de document : Thèse/HDR Auteurs : Philipp Flach, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2001 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 63 Importance : 175 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-05-5 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] analyse spectrale
[Termes IGN] détecteur à transfert de charge
[Termes IGN] filtre de Wiener
[Termes IGN] instrument de géodésie
[Termes IGN] instrumentation Leica
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle atmosphérique
[Termes IGN] réfraction atmosphérique
[Termes IGN] spectre électromagnétique
[Termes IGN] traitement d'image
[Termes IGN] turbulence
[Termes IGN] variance
[Termes IGN] vidéothéodoliteIndex. décimale : 30.03 Instruments de géodésie Résumé : (Auteur) The propagation path of light in the atmosphere is influenced by inhomogeneities of the refractive index. These refraction effects deteriorate the accuracy of the direction and distance measurements in geodetic applications. As illustrated by two examples in this report, the refraction effects cannot be accurately corrected up to now and, therefore, solutions must be provided which can be implemented into geodetic instruments. The presented approach is based on the determination of the temperature gradient being the decisive influential parameter for angular refraction effects.
In the atmosphere, temperature gradients are related to turbulent thermal exchange processes such as the turbulent sensible heat flux. In order to describe atmospheric turbulence, the applied statistical approach uses the method of spectral analysis which states that the atmospheric turbulent velocity field can be thought to consist of many eddies of different densities. This energy spectrum of turbulence can be modelled using the structure constant of refractive index CJ and the inner scale 10 of turbulence. If these two structure parameters are measured, the temperature gradient is derived from dimensionless profile functions using the so-called Monin-Obukhov similarity description. Hereby, the fact should be kept in mind, that the Monin-Obukhov similarity description and the energy spectrum of turbulence are only valid for vertical temperature gradient profiles in the atmospheric boundary layer.
This research work investigates the determination of the required structure parameter Cn and lo by means of image sensors which can be built into geodetic instruments. To derive the structure parameters CJ and 10 from the acquired image data, the application of appropriate image processing techniques is examined. The evaluation concept is based on angle-of-arrival fluctuations and intensity fluctuations. Angle-of-arrival fluctuations are perceived as high-frequency motions of image patterns grabbed by the sensor, and intensity fluctuations are related to the temporal variation of the gray values of the pixels. As presented in this report, these two effects of optical turbulence can be used to determine the structure parameter Cn and lo. For this purpose, image processing techniques must parameterize both angle-of-arrival fluctuations and intensity fluctuations. Within this research work, the angle-of-arrival fluctuations are modelled by the variance óx characterizing the shifting of image patterns which are located using edge detection algorithms. The intensity fluctuations are modelled by the variance óx characterizing the temporal intensity spectrum of the incoming light beam. In the scope of this research work, the variance óx is provided using digital filter techniques such as the Wiener filter or least-squares template matching.
In order to validate this concept, the video theodolite Leica TM3000V and a digital line scan camera Basler L120 are used as two different imaging systems to acquire image data during various practical field experiments. These field experiments revealed a partial good agreement between the structure parameter CJ and lo obtained by the image sensors and the ones obtained by a reference system (scintillometer). Basically, the method presented here is appropriate to reduce the refraction influence. A decisive advantage of this method is based on the fact that additional sensors are not necessary (except for the image sensors which are built into the instrument). However, as the exemplary comparison of temperature gradients shows at the end of the report, further research work in the scope of the atmospheric boundary layer is still necessary.Numéro de notice : 13062 Affiliation des auteurs : non IGN Autre URL associée : http://dx.doi.org/10.3929/ethz-a-004045114 Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-004045114 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-63.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54863 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13062-01 30.03 Livre Centre de documentation En réserve M-103 Disponible 13062-02 30.03 Livre Centre de documentation En réserve M-103 Disponible PermalinkDevelopment of a dispersometer for the implementation into geodetic high-accuracy direction measurement systems / Burkhard Böckem (2001)
PermalinkDevelopment of a solar spectro-irradiometer for the validation of remotely sensed hyperspectral images / A. Barducci (2001)
PermalinkEtude des relations spécifiques entre végétation et roches du massif de Ronda par télédétection hyperspectrale AVIRIS (1991) et HYMAP (2000) / Guillaume Hallereau (2001)
PermalinkPermalinkGenauigkeitsuntersuchungen zur GPS/INS-Integration in der Aerophotogrammetrie / Michael Cramer (2001)
PermalinkInfluence of the three-dimensional effects on the simulation of landscapes in thermal infrared / T. Poglio (2001)
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PermalinkA numerical analysis of the accuracy of laboratory and field goniometer measurements / N. Widen (2001)
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PermalinkPermalinkSpace gravity spectroscopy - The sensitivity analysis of GPS-tracked satellite missions (case study CHAMP) / C. Schäfer (2001)
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PermalinkThe use of global navigation satellite systems (GNSS) signals in numerical weather prediction (NWP) / Lidia Cucurull Molina (2001)
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PermalinkL'aventure SPOT, du temps des pionniers à la haute résolution / Philippe Munier in Géomètre, vol 2000 n° 10 (octobre 2000)
PermalinkThe Z-I imaging digital camera system / A. Hinze in Photogrammetric record, vol 16 n° 96 (October 2000 - March 2001)
Permalinkn° 159 - Juillet 2000 - Séminaire "Caractérisation géométrique en vol des systèmes imageurs optiques", [Actes], Bordeaux (France), 2 - 5 novembre 1999 = Seminar "In-orbit geometric characterization of optical imaging systems" (Bulletin de Bulletin [Société Française de Photogrammétrie et Télédétection]) / Société française de photogrammétrie et de télédétection
Permalinkvol 38 n° 4 Tome 1 - July 2000 - Special issue on computational wave issues in remote sensing, imaging and target identification, propagation and inverse scattering (Bulletin de IEEE Transactions on geoscience and remote sensing) / Geoscience and remote sensing society
Permalinkvol 51 n° 5 - May 2000 - Proceedings of the 3rd UNIGRACE working conference, [actes], Sofia, Bulgaria, 13 - 14 April 2000 (Bulletin de Reports on geodesy) / Bernd Richter
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PermalinkFusion of high spatial and spectral resolution images: the ARSIS concept and its implementation / Thierry Ranchin in Photogrammetric Engineering & Remote Sensing, PERS, vol 66 n° 1 (January 2000)
PermalinkGuidelines for the display of attribute certainty / Michael Leitner in Cartography and Geographic Information Science, vol 27 n° 1 (January 2000)
PermalinkL'initiative européenne de suivi global pour l'environnement et la sécurité de Kyoto : besoins en matière d'informations et de données associées / G. Begni in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 157 (Janvier 2000)
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PermalinkOberflächenrekonstruktion mit Hilfe einer Mehrbild-Shape-from-Shading-Methode / C. Piechullek (2000)
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