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Auteur Juha Hyyppä |
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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 Going 3D: personal Nav and LBS / R. Chen in GPS world, vol 21 n° 2 (February 2010)
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Titre : Going 3D: personal Nav and LBS Type de document : Article/Communication Auteurs : R. Chen, Auteur ; H. Kuusniemi, Auteur ; Juha Hyyppä, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 14 - 18 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] données multicapteurs
[Termes IGN] modèle 3D de l'espace urbain
[Termes IGN] navigation pédestre
[Termes IGN] positionnement par GNSS
[Termes IGN] service fondé sur la position
[Termes IGN] téléphone intelligent
[Termes IGN] téléphonie mobileRésumé : (Auteur) To enrich user experience of location-based services and personal navigation, three-dimensional models such as those used in urban planning are added to a smartphone platform, without the requirement of additional hardware. Copyright Questex Media Group Numéro de notice : A2010-025 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30221
in GPS world > vol 21 n° 2 (February 2010) . - pp 14 - 18[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-2010021 RAB Revue Centre de documentation En réserve L003 Disponible Small-footprint laser scanning simulator for system validation, error assessment, and algorithm development / Antero Kukko in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 10 (October 2009)
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Titre : Small-footprint laser scanning simulator for system validation, error assessment, and algorithm development Type de document : Article/Communication Auteurs : Antero Kukko, Auteur ; Juha Hyyppä, Auteur Année de publication : 2009 Article en page(s) : pp 1177 - 1189 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] classification orientée objet
[Termes IGN] détection de changement
[Termes IGN] données lidar
[Termes IGN] erreur systématique
[Termes IGN] faisceau laser
[Termes IGN] hauteur des arbres
[Termes IGN] instrumentation Toposys
[Termes IGN] modèle de simulation
[Termes IGN] précision décimétrique
[Termes IGN] semis de points
[Termes IGN] signal laser
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) Airborne lidar systems have come to be extensively used in photogrammetry and mapping sciences. In this paper, a high-quality simulation approach and methods of smallfootprint lidar processing are presented and discussed, validated for tree height estimation, and demonstrated for scanning geometry effects analysis and mobile mapping. The simulation method implemented combines both spatial and radiometric components to produce realistic waveform and point cloud data for system performance analysis and for algorithm development for lidar data processing and mapping purposes. Waveform data generated by the simulator were shown to demonstrate the possibilities of such an approach in system and data verification. As the related empirical data are insufficient for effective research and exploitation in mapping purposes at the moment, the simulated waveform data are needed. A tree location accuracy of 15 cm and tree height underestimation of 0.33 m was found using the simulation model for the TopEye Mk II laser scanner, compared to the artificial forest model reference data. Modeling of light interaction on object surfaces and characteristics of scanning systems provide an opportunity to simulate laser data acquisition of well-defined objects under controlled conditions. By eliminating different sources of error case-by-case, we can improve the knowledge obtained merely from the experimental studies. Data validation in the scanning geometry simulations was carried out by comparing the simulated first echo data to the environment model and, separately, to the first echo data from an independent TopoSys II flight strip that was not used for the environment model computation. The mean differences reveal that the simulator slightly overestimates the object elevations. Deviation between the real TopoSys point cloud and the environmental model was 2 to 3 times larger than that obtained for the simulated Optech and TopoSys data sets.
We believe that the developed simulation and modeling is an efficient tool for determining the most reasonable set of flight parameters for any current mapping task, for analyzing change detection possibilities of repeated laser surveys, and for studying and verifying future lidar systems and concepts. However, this requires high-quality modeling of the system and extensive knowledge of the interaction between the laser beam and the object, which should be further developed in the coming years. Copyright ASPRSNuméro de notice : A2009-419 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.75.10.1177 En ligne : https://doi.org/10.14358/PERS.75.10.1177 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30050
in Photogrammetric Engineering & Remote Sensing, PERS > vol 75 n° 10 (October 2009) . - pp 1177 - 1189[article]Radiometric Calibration of LIDAR Intensity With Commercially Available Reference Targets / S. Kaasalainen in IEEE Transactions on geoscience and remote sensing, vol 47 n° 2 (February 2009)
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Titre : Radiometric Calibration of LIDAR Intensity With Commercially Available Reference Targets Type de document : Article/Communication Auteurs : S. Kaasalainen, Auteur ; Juha Hyyppä, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 588 - 598 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] détection de cible
[Termes IGN] données lidar
[Termes IGN] étalonnage radiométrique
[Termes IGN] intensité lumineuse
[Termes IGN] Lidar
[Termes IGN] luminance lumineuse
[Termes IGN] objet géographique ponctuel
[Termes IGN] réflectance
[Termes IGN] rétrodiffusionRésumé : (Auteur) We present a new approach for radiometric calibration of light detection and ranging (LIDAR) intensity data and demonstrate an application of this method to natural targets. The method is based on 1) using commercially available sand and gravel as reference targets and 2) the calibration of these reference targets in the laboratory conditions to know their backscatter properties. We have investigated the target properties crucial for accurate and consistent reflectance calibration and present a set of ideal targets easily available for calibration purposes. The first results from LIDAR-based brightness measurement of grass and sand show that the gravel-based calibration approach works in practice, is cost effective, and produces statistically meaningful results: Comparison of results from two separate airborne laser scanning campaigns shows that the relative calibration produces repeatable reflectance values. Copyright IEEE Numéro de notice : A2009-023 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2008.2003351 En ligne : https://doi.org/10.1109/TGRS.2008.2003351 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29653
in IEEE Transactions on geoscience and remote sensing > vol 47 n° 2 (February 2009) . - pp 588 - 598[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-09021 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : EuroSDR ISPRS project, commission 2 tree extraction: final report Type de document : Rapport Auteurs : Harri Kaartinen, Auteur ; Juha Hyyppä, Auteur ; European Spatial Data Research EuroSDR, Auteur Editeur : Dublin : European Spatial Data Research EuroSDR Année de publication : 2008 Collection : EuroSDR official publication, ISSN 0257-0505 num. 53 Importance : 60 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-90-5179-598-X Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse comparative
[Termes IGN] arbre (flore)
[Termes IGN] canopée
[Termes IGN] données lidar
[Termes IGN] étude de faisabilité
[Termes IGN] extraction automatique
[Termes IGN] extraction du sursol
[Termes IGN] extraction semi-automatique
[Termes IGN] forêt
[Termes IGN] hauteur des arbres
[Termes IGN] image aérienne
[Termes IGN] lasergrammétrie
[Termes IGN] qualité des donnéesIndex. décimale : 35.20 Traitement d'image Résumé : (Auteur) The objective of the EuroSDR/ISPRS Tree Extraction project was to evaluate the quality, accuracy, and feasibility of automatic or semi-automatic tree extraction methods based on high-density laser scanner data and digital image data. Data sets from two test sites were delivered to the twelve participants of the project. For each test site the following data were available and could be downloaded from the FGI ftp-site: aerial images, camera calibration and image orientation information, ground control point coordinates and jpg-images of point locations, laser scanner data with three different pulse densities, digital terrain model and a training data set. In this report the test sites used, data sets and the reference data are described. The tree extraction methods used by the participants and methods used in accuracy evaluation are explained in this report. The produced tree models are depicted and analysed with respect to tree location, tree height, crown base height and crown delineation accuracy. Finally, a discussion and conclusions chapter summarise the results of the project. Surprisingly, results show that the extraction method is the main factor on the achieved accuracy. When the laser point density increases from two points to eight points per m2, the improvement in crown base height and crown delineation accuracy is marginal but in the case of some methods the accuracy of the tree location and especially the tree height determination improves. The low number of hybrid models based on both the laser data and aerial image produced by the partners implies that integration of laser and aerial image is in its early stages. Numéro de notice : 15391 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Rapport En ligne : http://www.eurosdr.net/sites/default/files/uploaded_files/eurosdr_publication_nd [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=40674 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15391-01 35.20 Livre Centre de documentation Télédétection Disponible A test of 2D building change detection methods : comparison, evaluation and perspectives / Nicolas Champion (2008)PermalinkProceedings of the ISPRS Workshop 'Laser Scanning 2007 and SilviLaser 2007' September 12-14, 2007 Espoo, Finland / Petri Rönnholm (2007)PermalinkChange detection techniques for canopy height growth measurements using airborne laser scanner data / X. Yu in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 12 (December 2006)PermalinkDetermination of exterior orientation using linear features from vector maps / Mika Karjalainen in Photogrammetric record, vol 21 n° 116 (December 2006 - February 2007)PermalinkGeometric test field calibration of digital photogrammetric sensors / Eija Honkavaara in ISPRS Journal of photogrammetry and remote sensing, vol 60 n° 6 (September 2006)PermalinkMapping built-up areas from multitemporal interferometric SAR images: a segment-based approach / Leena Matikainen in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 6 (June 2006)PermalinkUse of HRSC-A for sampling bidirectional reflectance / Antero Kukko in ISPRS Journal of photogrammetry and remote sensing, vol 59 n° 6 (November 2005)PermalinkPermalinkPermalink