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An adaptive approach to topographic feature extraction from Digital Terrain Models / Y. Song in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 3 (March 2009)
[article]
Titre : An adaptive approach to topographic feature extraction from Digital Terrain Models Type de document : Article/Communication Auteurs : Y. Song, Auteur ; J. Shan, Auteur Année de publication : 2009 Article en page(s) : pp 281 - 290 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] Antarctique
[Termes IGN] carte des pentes
[Termes IGN] extraction automatique
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] modèle numérique de terrain
[Termes IGN] seuillageRésumé : (Auteur) This study presents an adaptive solution to topographic feature extraction from digital terrain model. First, a slope map is produced by the proposed slope estimator that combines the well-known D8 and finite difference methods. In the second step, the Laplacian of Gaussian (LOG) operator with multiple thresholds is applied to the resultant slope map to determine edge pixels that have local maximum curvature and maximum connectivity. The third step adopts the original and robust marching square algorithms to trace the topographic features. Modification is made to selectively introduce shoulder points according to the local topographic complexity. In comparison to the existing algorithms, the performance of the proposed adaptive marching square algorithm is evaluated in terms of precision and resolution of the extracted features. Digital terrain models over three locations in Antarctica are used for this study. It is shown overall reducing 75 percent of the shoulder points from the robust algorithm will cause 24 percent precision drop in the adaptive method. Copyright ASPRS Numéro de notice : A2009-038 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.75.3.281 En ligne : https://doi.org/10.14358/PERS.75.3.281 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29668
in Photogrammetric Engineering & Remote Sensing, PERS > vol 75 n° 3 (March 2009) . - pp 281 - 290[article]Reconstructing spatiotemporal trajectories from sparse data / P. Partsinevelos in ISPRS Journal of photogrammetry and remote sensing, vol 60 n° 1 (December 2005 - March 2006)
[article]
Titre : Reconstructing spatiotemporal trajectories from sparse data Type de document : Article/Communication Auteurs : P. Partsinevelos, Auteur ; Peggy Agouris, Auteur ; A. Stefanidis, Auteur Année de publication : 2005 Article en page(s) : pp 3 - 16 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] analyse de groupement
[Termes IGN] carte de Kohonen
[Termes IGN] classification dirigée
[Termes IGN] classification par réseau neuronal
[Termes IGN] données spatiotemporelles
[Termes IGN] modélisation spatio-temporelle
[Termes IGN] objet mobile
[Termes IGN] reconstruction d'itinéraire ou de trajectoire
[Termes IGN] segmentation
[Termes IGN] seuillageRésumé : (Auteur) In motion imagery-based tracking applications, it is common to extract locations of moving objects without any knowledge about the identity of the objects they correspond to. The identification of individual spatiotemporal trajectories from such data sets is far from trivial when these trajectories intersect in space, time, or attributes. In this paper, we present a novel approach for the reconstruction of entangled spatiotemporal trajectories of moving objects captured in motion imagery data sets. We have developed AGENT (Attribute-aided Classification of Entangled Trajectories), a novel framework that comprises classification, clustering, and neural net processes to progressively reconstruct elongated trajectories using as input spatiotemporal coordinates of image patches and corresponding attribute values. AGENT proceeds by first forming brief fragments and then linking them and adding points to them. An initial classification allows us to form brief segments corresponding to distinct objects. These segments are then linked together through clustering to form longer trajectories. Back-propagation neural network classification and geometric/self-organizing map (SOM) analysis refine these trajectories by removing misclassified and redistributing unassigned points. Thus, AGENT integrates some established classification and clustering tools to devise a novel approach that can address the tracking challenges of busy environments. Furthermore, AGENT allows us use spatiotemporal (ST) thresholds to cluster trajectories according to their spatial and temporal extent. In the paper, we present in detail our framework and experimental results that support the application potential of our approach. Numéro de notice : A2006-218 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2005.10.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2005.10.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27945
in ISPRS Journal of photogrammetry and remote sensing > vol 60 n° 1 (December 2005 - March 2006) . - pp 3 - 16[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-06011 SL Revue Centre de documentation Revues en salle Disponible A framework to enhance semantic flexibility for analysis of distributed phenomena / J Mcintosh in International journal of geographical information science IJGIS, vol 19 n° 10 (november 2005)
[article]
Titre : A framework to enhance semantic flexibility for analysis of distributed phenomena Type de document : Article/Communication Auteurs : J Mcintosh, Auteur ; M. Yuan, Auteur Année de publication : 2005 Article en page(s) : pp 999 - 1018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse d'image orientée objet
[Termes IGN] analyse spatiale
[Termes IGN] distribution spatiale
[Termes IGN] données maillées
[Termes IGN] données vectorielles
[Termes IGN] information sémantique
[Termes IGN] modèle conceptuel de données spatio-temporelles
[Termes IGN] modèle logique de données
[Termes IGN] problème des valeurs limites
[Termes IGN] représentation des détails topographiques
[Termes IGN] représentation multiple
[Termes IGN] requête spatiotemporelle
[Termes IGN] seuillage
[Termes IGN] système d'information géographique
[Termes IGN] varianceRésumé : (Auteur) While some geographic phenomena hold uniform properties, such as land-use zones, many geographic phenomena are distributed such that their properties vary across an extended area. While such distributed phenomena are best represented as continuous surfaces, individual objects (or features) often emerge among clusters of high or low values in a field. For example, areas of relatively high elevation may be viewed as hills, while flat low-lying areas are perceived as plains in a terrain. A comprehensive spatial analysis of distributed phenomena should examine both the spatial variance of its attribute surfaces and the characteristics of individual objects embedded in the field. An immediate research challenge to meet such spatial analysis needs is that these emerging features often have vague boundaries that vary according to the use and the user. The nature, and even existence, of these objects depend upon the range of values, or thresholds, used to define them. We propose a representation framework that takes a dual raster-vector approach to capture both field- and object-like characteristics of distributed phenomena and maintain multiple representations of embedded features delineated by boundaries that are likely to be relevant for the expected uses of the data. We demonstrate how boundaries influence the analysis and understanding of spatiotemporal characteristics of distributed phenomena. Using precipitation as a proof of concept, we show how the proposed framework enhances semantic flexibility in spatiotemporal query and analysis of distributed phenomena in geographic information systems. Numéro de notice : A2005-496 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810500197652 En ligne : https://doi.org/10.1080/13658810500197652 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27632
in International journal of geographical information science IJGIS > vol 19 n° 10 (november 2005) . - pp 999 - 1018[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-05091 RAB Revue Centre de documentation En réserve L003 Disponible 079-05092 RAB Revue Centre de documentation En réserve L003 Disponible Fundamentals of radar signal processing / M. Richards (2005)
Titre : Fundamentals of radar signal processing Type de document : Monographie Auteurs : M. Richards, Auteur Editeur : Boston, New York, ... : McGraw-Hill Année de publication : 2005 Collection : Electronic Engineering Importance : 513 p. Format : 19 x 24 cm ISBN/ISSN/EAN : 978-0-07-144474-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] correction du signal
[Termes IGN] échantillonnage de signal
[Termes IGN] écho radar
[Termes IGN] effet Doppler
[Termes IGN] filtrage linéaire
[Termes IGN] forme d'onde
[Termes IGN] image radar moirée
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] radar à antenne synthétique
[Termes IGN] radargrammétrie
[Termes IGN] rapport signal sur bruit
[Termes IGN] seuillage
[Termes IGN] télédétection en hyperfréquence
[Termes IGN] traitement du signal
[Termes IGN] transformation de FourierIndex. décimale : 35.22 Télédétection en hyperfréquence - Traitement d'image radar Résumé : (Editeur) [...] This rigorous text provides detailed coverage of radar digital signal processing (DSP) fundamentals and applications not to be found elseewhere in the literature. [...] It provides clear modern instruction in radar DSP basics and the skills needed in both design and analysis of common radar algorithms. This text is ideal for those looking to go beyond the cursory treatment of signal processing in general radar systems books to seeek more detailed tratments of signal models, waveforms, interference reduction and detection, as well as to gain the foundation needed for specialty texts that focus on advanced radar signal processing topics such as SAR and STAP (Space- Time Adaptive Processing). Note de contenu : Chapter 1 : Introduction to Radar Systems
Chapter 2 : Signal Models
Chapter 3 : Sampling and Quantization of Pulsed Radar Signals
Chapter 4 : Radar Waveforms
Chapter 5 : Doppler Processing
Chapter 6 : Detection Fundamentals
Chapter 7 : Constant False Alarm Rate (CFAR) Detection
Chapter 8 : Introduction to Synthetic Aperture Radar
Chapter 9 : Introduction to Adaptive Beamforming and Space-Time Adaptive ProcessingNuméro de notice : 20107 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62916 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 20107-01 35.22 Livre Centre de documentation Télédétection Disponible The effect of broadleaf canopies on survey-grade horizontal GPS-GLONASS measurements / Thomas H. Meyer in Surveying and land information systems, vol 62 n° 4 (01/12/2002)
[article]
Titre : The effect of broadleaf canopies on survey-grade horizontal GPS-GLONASS measurements Type de document : Article/Communication Auteurs : Thomas H. Meyer, Auteur ; J.E. Bean, Auteur ; C.R. Ferguson, Auteur ; J.M. Naismith, Auteur Année de publication : 2002 Article en page(s) : pp 215 - 224 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] diffusion du rayonnement
[Termes IGN] feuille (végétation)
[Termes IGN] instrumentation Trimble
[Termes IGN] ligne de base
[Termes IGN] positionnement par GLONASS
[Termes IGN] positionnement par GPS
[Termes IGN] récepteur GPS
[Termes IGN] récepteur mixte
[Termes IGN] seuillage
[Termes IGN] signal GLONASS
[Termes IGN] signal GPSRésumé : (Auteur) A study was conducted to empirically determine the degradation of survey-grade GPS horizontal position measurements due to the effects of broadleaf forest canopies. The measurements were taken using GPS/GLONASS-capable receivers measuring C/A and P-codes, and carrier phase. Fourteen survey markers were chosen in central Connecticut to serve as reference makers for study. These markers had varying degrees of sky obstruction due to overhanging tree canopies. Sky obstruction was measured by photographing the sky with a 35 mm reflex camera fitted with a hemispherical lens. The negative was scanned and the image mapped using an equal-area projection to remove the distortion caused by the lens. The resulting digital image was thresholded to produce a black-and-white image in which a count of the black pixels is a measure of sky-area obstruction. The locations of the markers were determined independently before the study. During the study, each marker was occupied for four 20-minutes sessions over the period of one week in mid-july 1999. The locations of the study markers produced relatively long baselines, as compared with similar studies. We compared the accuracy of GPS-only vs. GPS&GLONASS as a function of sky obstruction. Based on our results, GLONASS observations did not improve of degrade the accuracy of the position measurements. There is a loss of 2 mm of accuracy per percent of sky obstruction for both GPS only and GPS&GLONASS. Numéro de notice : A2002-360 Affiliation des auteurs : non IGN Thématique : FORET/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22271
in Surveying and land information systems > vol 62 n° 4 (01/12/2002) . - pp 215 - 224[article]