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Range and AGC normalization in airborne discrete-return LiDAR intensity data for forest canopies / Ilkka Korpela in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 4 (July - August 2010)
[article]
Titre : Range and AGC normalization in airborne discrete-return LiDAR intensity data for forest canopies Type de document : Article/Communication Auteurs : Ilkka Korpela, Auteur ; Hans Ole Ørka, Auteur ; Juha Hyyppä, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 369 - 379 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] couvert forestier
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] espèce végétale
[Termes IGN] Finlande
[Termes IGN] forêt boréale
[Termes IGN] lasergrammétrie
[Termes IGN] Pinophyta
[Termes IGN] précision de la classification
[Termes IGN] signal laserRésumé : (Auteur) Recently, the intensity characteristics of discrete-return LiDAR sensors were studied for vegetation classification. We examined two normalization procedures affecting LiDAR intensity through the scanning geometry and the system settings, namely, range normalization and the effects of the automatic gain control (AGC) in the Optech ALTM3100 and Leica ALS50-II sensors. Range normalization corresponds to weighting of the observed intensities with the term (R/RRef)a , where R is the range, RRef is a mean reference range, and aset membership, variant[2,4] is the exponent that is, according to theory, dependent on the target geometry. LiDAR points belonging to individual tree crowns were extracted for 13 887 trees in southern Finland. The coefficient of variation (CV) of the intensity was analyzed for a range of values of exponent a. The tree species classification performance using 13 intensity variables was also used for sensitivity analysis of the effect of a. The results were in line with the established theory, since the optimal level of a was lower (a~2) for trees with large or clumped leaves and higher (a~3) for diffuse coniferous crowns. Different echo groups also showed varying responses. Single-return pulses that represented strong reflections had a lower optimal value of a than the first and all echoes in a pulse. The gain in classification accuracy from the optimal selection of the exponent was 2%–3%, and the optimum for classification was different from that obtained using the CV analysis. In the ALS50-II sensor, the combined and optimized AGC and R normalizations had a notably larger effect (6%–9%) on classification accuracy. Our study demonstrates the ambiguity of R normalization in vegetation canopies. Numéro de notice : A2010-297 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.04.003 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.04.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30491
in ISPRS Journal of photogrammetry and remote sensing > vol 65 n° 4 (July - August 2010) . - pp 369 - 379[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2010041 SL Revue Centre de documentation Revues en salle Disponible Spatial autoregressive model for population estimation at the census block level using lidar-derived building volume information / F. Qiu in Cartography and Geographic Information Science, vol 37 n° 3 (July 2010)
[article]
Titre : Spatial autoregressive model for population estimation at the census block level using lidar-derived building volume information Type de document : Article/Communication Auteurs : F. Qiu, Auteur ; H. Sridharan, Auteur ; Y. Chun, Auteur Année de publication : 2010 Article en page(s) : pp 239 - 257 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] auto-régression
[Termes IGN] bati
[Termes IGN] densité de population
[Termes IGN] données lidar
[Termes IGN] recensement démographiqueRésumé : (Auteur) The collection of population by census is laborious, time consuming and expensive, and often only available at limited temporal and spatial scales. Remote sensing based population estimation has been employed as a viable alternative for providing population estimates based on indicators that make use of two-dimensional areal information of buildings or one-dimensional length information of roads The recent advancement of LIDAR remote sensing provides the opportunity to add the third dimension of height information into the modeling of population distribution. This study explores the use of building volumes derived from LIDAR as a population indicator. Our study shows the volume-based model consistently outperforms area and length-based models at the census block level. Additionally, the study examines the impact of spatial autocorrelation, the presence of which violates the independence assumption of the traditional OLS models. To address this problem, a spatial autoregressive model is employed to account for the spatial autocorrelation in the regression residuals. By incorporating the spatial pattern, the volume-based spatial error model achieves a goodness of fit (R2) of 85 percent, with a significant improvement in model performance and estimation accuracies in comparison with its OLS counterpart. The study confirms building volume as a more valuable indicator and estimator for block level population distribution, especially if an appropriate spatial autoregressive model is adopted. Numéro de notice : A2010-358 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1559/152304010792194949 En ligne : https://doi.org/10.1559/152304010792194949 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30552
in Cartography and Geographic Information Science > vol 37 n° 3 (July 2010) . - pp 239 - 257[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-2010031 RAB Revue Centre de documentation En réserve L003 Disponible Approximating covariance matrices estimated in multivariate models by estimated auto- and cross-covariances / Karl Rudolf Koch in Journal of geodesy, vol 84 n° 6 (June 2010)
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Titre : Approximating covariance matrices estimated in multivariate models by estimated auto- and cross-covariances Type de document : Article/Communication Auteurs : Karl Rudolf Koch, Auteur ; H. Kukhlmann, Auteur ; W. Schuh, Auteur Année de publication : 2010 Article en page(s) : pp 383 - 397 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] covariance
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] matrice de covariance
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle linéaireRésumé : (Auteur) Quantities like tropospheric zenith delays or station coordinates are repeatedly measured at permanent VLBI or GPS stations so that time series for the quantities at each station are obtained. The covariances of these quantities can be estimated in a multivariate linear model. The covariances are needed for computing uncertainties of results derived from these quantities. The covariance matrix for many permanent stations becomes large, the need for simplifying it may therefore arise under the condition that the uncertainties of derived results still agree. This is accomplished by assuming that the different time series of a quantity like the station height for each permanent station can be combined to obtain one time series. The covariance matrix then follows from the estimates of the auto- and cross-covariance functions of the combined time series. A further approximation is found, if compactly supported covariance functions are fitted to an estimated autocovariance function in order to obtain a covariance matrix which is representative of different kinds of measurements. The simplification of a covariance matrix estimated in a multivariate model is investigated here for the coordinates of points of a grid measured repeatedly by a laserscanner. The approximations are checked by determining the uncertainty of the sum of distances to the points of the grid. To obtain a realistic value for this uncertainty, the covariances of the measured coordinates have to be considered. Three different setups of measurements are analyzed and a covariance matrix is found which is representative for all three setups. Covariance matrices for the measurements of laserscanners can therefore be determined in advance without estimating them for each application. Numéro de notice : A2010-282 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-010-0375-5 Date de publication en ligne : 19/03/2010 En ligne : https://doi.org/10.1007/s00190-010-0375-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30476
in Journal of geodesy > vol 84 n° 6 (June 2010) . - pp 383 - 397[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2010061 SL Revue Centre de documentation Revues en salle Disponible Effects of topographic variability and Lidar sampling density on several DEM interpolation methods / Q. Guo in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 6 (June 2010)
[article]
Titre : Effects of topographic variability and Lidar sampling density on several DEM interpolation methods Type de document : Article/Communication Auteurs : Q. Guo, Auteur ; W. Li, Auteur ; H. Yu, Auteur ; O. Alvarez, Auteur Année de publication : 2010 Article en page(s) : pp 701 - 712 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] classification barycentrique
[Termes IGN] densité des points
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] fonction spline d'interpolation
[Termes IGN] interpolation
[Termes IGN] interpolation inversement proportionnelle à la distance
[Termes IGN] krigeage
[Termes IGN] modèle numérique de terrain
[Termes IGN] Triangulated Irregular Network
[Termes IGN] variabilitéRésumé : (Auteur) This study aims to quantify the effects of topographic variability (measured by coefficient variation of elevation, CV) and lidar (Light Detection and Ranging) sampling density on the DEM (Digital Elevation Model) accuracy derived from several interpolation methods at different spatial resolutions. Interpolation methods include natural neighbor (NN), inverse distance weighted (IDW), triangulated irregular network (TIN), spline, ordinary kriging (OK), and universal kriging (UK). This study is unique in that a comprehensive evaluation of the combined effects of three influencing factors (CV, sampling density, and spatial resolution) on lidar-derived DEM accuracy is carried out using different interpolation methods. Results indicate that simple interpolation methods, such as IDW, NN, and TIN, are more efficient at generating DEMs from lidar data, but kriging-based methods, such as OK and UK, are more reliable if accuracy is the most important consideration. Moreover, spatial resolution also plays an important role when generating DEMs from lidar data. Our results could be used to guide the choice of appropriate lidar interpolation methods for DEM generation given the resolution, sampling density, and topographic variability. Numéro de notice : A2010-228 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.76.6.701 En ligne : https://doi.org/10.14358/PERS.76.6.701 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30422
in Photogrammetric Engineering & Remote Sensing, PERS > vol 76 n° 6 (June 2010) . - pp 701 - 712[article]A novel approach to terrestrial Lidar georeferencing / B. Wilkinson in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 6 (June 2010)
[article]
Titre : A novel approach to terrestrial Lidar georeferencing Type de document : Article/Communication Auteurs : B. Wilkinson, Auteur ; A. Mohamed, Auteur ; B. Dewitt, Auteur ; G. Seedahmed, Auteur Année de publication : 2010 Article en page(s) : pp 683 - 690 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] géoréférencement direct
[Termes IGN] orientation absolue
[Termes IGN] semis de points
[Termes IGN] télémétrie laser terrestreRésumé : (Auteur) This paper describes a novel method for determining the absolute orientation of lidar point clouds using GPS measurements from two antennas firmly mounted on the optical head of a lidar scanner. The solution is linear and is derived from the non-linear georeferencing model by exploiting the properties of the skew-symmetric matrix. Simulation and real world experimentation using our prototype suggest a precision of about 0.05° (+_ 1 mrad) for the three Euler attitude angles. The method can help alleviate problems associated with the conventional technique and can allow for an increased number of practical applications for georeferenced terrestrial lidar. Numéro de notice : A2010-227 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.76.6.683 En ligne : https://doi.org/10.14358/PERS.76.6.683 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30421
in Photogrammetric Engineering & Remote Sensing, PERS > vol 76 n° 6 (June 2010) . - pp 683 - 690[article]Apport de la télédétection Lidar aéroporté haute définition pour la caractérisation de la végétation des digues / Michel Vennetier in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkLa canopée forestière vue par un Lidar ultra-violet aéroporté de nouvelle génération / J. Cuesta in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkDetection of sinkhole hazards using Airborne Laser Scanning Data / S. Filin in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 5 (May 2010)PermalinkDétection des variations de structure de peuplements en forêt dense tropicale humide par Lidar aéroporté / G. Vincent in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkExtraction de paramètres d'arbre à partir de modèles numériques de canopée Lidar / Cédric Vega in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkGeneration of complex polyhedral building models by integrating stereo-aerial imagery and Lidar data / A. Habib in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 5 (May 2010)PermalinkIdentification de morphologies pariétales en grotte à partir d'un lever laser 3D : application aux salles rouges de l'aven d'Orgnac (Ardèche, France) / Stéphane Jaillet in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkReconstruction de façades par des primitives géométriques à partir de données laser terrestres / Hakim Boulaassal in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkSegmentation et interprétation de nuages de points pour la modélisation d'environnements urbains / J. Hernandez in Revue Française de Photogrammétrie et de Télédétection, n° 191 (Mai 2010)PermalinkThe Forward Propagation of Integrated System Component Errors within Airborne Lidar Data / T. Goulden in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 5 (May 2010)Permalink