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Mapping the height and above-ground biomass of a mixed forest using lidar and stereo Ikonos images / Benoît Saint-Onge in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1277 - 1294 Titre : Mapping the height and above-ground biomass of a mixed forest using lidar and stereo Ikonos images Type de document : Article/Communication Auteurs : Benoît Saint-Onge, Auteur ; Y. Hu, Auteur ; Cédric Vega , Auteur Année de publication : 2008 Article en page(s) : pp 1277 - 1294 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] canopée [Termes IGN] données lidar [Termes IGN] forêt [Termes IGN] hauteur des arbres [Termes IGN] image à résolution métrique [Termes IGN] image Ikonos [Termes IGN] masse végétale [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique de terrain [Termes IGN] modèle stéréoscopique Résumé : (Auteur) Our objective was to assess the accuracy of the forest height and biomass estimates derived from an Ikonos stereo pair and a lidar digital terrain model (DTM). After the Ikonos scenes were registered to the DTM with submetric accuracy, tree heights were measured individually by subtracting the photogrammetric elevation of the treetop from the lidar ground-level elevation of the tree base. The low residual error (1.66 m) of the measurements confirmed the joint geometric accuracy of the combined models. Matched images of the stereo pair were then used to create a digital surface model. The latter was transformed to a canopy height model (CHM) by subtracting the lidar DTM. Plotwise height percentiles were extracted from the Ikonos-lidar CHM and used to predict the average dominant height and above-ground biomass. The coefficient of determination reached 0.91 and 0.79 for average height and biomass, respectively. In both cases, the accuracy of the Ikonos-lidar CHM predictions was slightly lower than that of the all-lidar reference CHM. Although the CHM heights did not saturate at moderate biomass levels, as do multispectral or radar images, values above 300 Mg ha-1 could not be predicted accurately by the Ikonos-lidar or by the all-lidar CHM. Copyright Taylor & Francis Numéro de notice : A2008-080 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736505 En ligne : https://doi.org/10.1080/01431160701736505 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29075 [article]

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Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning / F. Morsdorf in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1387 - 1406 Titre : Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning Type de document : Article/Communication Auteurs : F. Morsdorf, Auteur ; O. Frey, Auteur ; E. Meier, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 1387 - 1406 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] altitude du capteur [Termes IGN] angle d'incidence [Termes IGN] angle de visée [Termes IGN] couvert végétal [Termes IGN] données laser [Termes IGN] hauteur des arbres [Termes IGN] instrumentation Toposys [Termes IGN] Leaf Area Index [Termes IGN] modèle numérique de terrain [Termes IGN] parc naturel [Termes IGN] plan de vol [Termes IGN] signal laser [Termes IGN] Suisse [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Airborne Laser Scanning (ALS) has been established as a valuable tool for the estimation of biophysical vegetation properties such as tree height, crown width, fractional cover and leaf area index (LAI). It is expected that the conditions of data acquisition, such as viewing geometry and sensor configuration influence the value of these parameters. In order to gain knowledge about these different conditions, we test for the sensitivity of vegetation products for viewing geometry, namely flying altitude and scanning (incidence) angle. Based on two methodologies for single tree extraction and derivation of fractional cover and LAI previously developed and published by our group, we evaluate how these variables change with either flying altitude or scanning angle. These are the two parameters which often need to be optimized towards the best compromise between point density and area covered with a single flight line, in order to reduce acquisition costs. Our test-site in the Swiss National Park was sampled with two nominal flying altitudes, 500 and 900 m above ground. Incidence angle and local incidence angle were computed based on the digital terrain model using a simple backward geocoding procedure. We divided the raw laser returns into several different incident angle classes based on the flight path data; the TopoSys Falcon II system used in this study has a maximum scan angle of + 7.15°. We compared the derived biophysical properties from each of these classes with field measurements based on tachymeter measurements and hemispherical photographs, which were geolocated using differential GPS. It was found that with increasing flying height the well-known underestimation of tree height increases. A similar behaviour can be observed for fractional cover; its respective values decrease with higher flying height. The minimum distance between first and last echo increases from 1.2 metres for 500 m AGL to more than 3 metres for 900 m AGL, which does alter return statistics. The behaviour for incidence angles is not so evident, probably due to the small scanning angle of the system used. fCover seems to be most affected by incidence angles, with significantly higher differences for locations further away from nadir. As expected, incidence angle appears to be of higher importance for vegetation density parameters than local incidence angle. Numéro de notice : A2008-081 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736349 En ligne : https://doi.org/10.1080/01431160701736349 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29076 [article]

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3D vegetation mapping using small-footprint full-waveform airborne laser scanners / W. Wagner in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1433 - 1452 Titre : 3D vegetation mapping using small-footprint full-waveform airborne laser scanners Type de document : Article/Communication Auteurs : W. Wagner, Auteur ; Markus Hollaus, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 1433 - 1452 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] carte de la végétation [Termes IGN] données localisées 3D [Termes IGN] lidar à retour d'onde complète [Termes IGN] modèle numérique de terrain [Termes IGN] rayonnement infrarouge [Termes IGN] semis de points [Termes IGN] signal laser [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Small-footprint full-waveform airborne laser scanning (ALS) is a remote sensing technique capable of mapping vegetation in three dimensions with a spatial sampling of about 0.5-2 m in all directions. This is achieved by scanning the laser beam across the Earth's surface and by emitting nanosecond-long infrared pulses with a high frequency of typically 50-150 kHz. The echo signals are digitized during data acquisition for subsequent off-line waveform analysis. In addition to delivering the three-dimensional (3D) coordinates of scattering objects such as leaves or branches, full-waveform laser scanners can be calibrated for measuring the scattering properties of vegetation and terrain surfaces in a quantitative way. As a result, a number of physical observables are obtained, such as the width of the echo pulse and the backscatter cross-section, which is a measure of the electromagnetic energy intercepted and re-radiated by objects. The main aim of this study was to build up an understanding of the scattering characteristics of vegetation and the underlying terrain. It was found that vegetation typically causes a broadening of the backscattered pulse, while the backscatter cross-section is usually smaller for canopy echoes than for terrain echoes. These scattering properties allowed classification of the 3D point cloud into vegetation and non-vegetation echoes with an overall accuracy of 89.9% for a dense natural forest and 93.7% for a baroque garden area. In addition, by removing the vegetation echoes before the filtering process, the quality of the digital terrain model could be improved. Copyright Taylor & Francis Numéro de notice : A2008-082 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736398 En ligne : https://doi.org/10.1080/01431160701736398 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29077 [article]

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Species identification of individual trees by combining high resolution LiDAR data with multi-spectral images / Johan Holmgren in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1537 - 1552 Titre : Species identification of individual trees by combining high resolution LiDAR data with multi-spectral images Type de document : Article/Communication Auteurs : Johan Holmgren, Auteur ; A. Persson, Auteur ; U. Sodermans, Auteur Année de publication : 2008 Article en page(s) : pp 1537 - 1552 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse discriminante [Termes IGN] données lidar [Termes IGN] flore locale [Termes IGN] houppier [Termes IGN] identification automatique [Termes IGN] image multibande [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] Picea abies [Termes IGN] Pinus sylvestris [Termes IGN] Suède [Termes IGN] sylviculture [Termes IGN] traitement du signal Résumé : (Auteur) The objectives of this study were to identify useful predictive factors for tree species identification of individual trees and to compare classifications based on a combination of LiDAR data and multi-spectral images with classification by the use of each individual data source. Crown segments derived from LiDAR data were mapped to multi-spectral images for extraction of spectral data within individual tree crowns. Several features, related to height distribution of laser returns in the canopy, canopy shape, proportion of different types of laser returns, and intensity of laser returns, were derived from LiDAR data. Data from a test site in southern Sweden were used (lat. 58°30' N, long. 13°40' E). The forest consisted of Norway spruce (Picea abies), Scots pine (Pinus sylvestris), and deciduous trees. Classification into these three tree species groups was validated for 1711 trees that had been detected in LiDAR data within 14 field plots (sizes of 20x50 m or 80x80 m). The LiDAR data were acquired by the TopEye MkII system (50 LiDAR measurements per m) and the multi-spectral images were taken by the Zeiss/Intergraph Digital Mapping Camera. The overall classification accuracy was 96% when both data sources were combined. Copyright Taylor & Francis Numéro de notice : A2008-083 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736471 En ligne : https://doi.org/10.1080/01431160701736471 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29078 [article]

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Automatic forest inventory parameter determination from terrestrial laser scanner data / Hans-Gerd Maas in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1579 - 1593 Titre : Automatic forest inventory parameter determination from terrestrial laser scanner data Type de document : Article/Communication Auteurs : Hans-Gerd Maas, Auteur ; A. Bienert, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 1579 - 1593 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données laser [Termes IGN] données localisées 3D [Termes IGN] hauteur des arbres [Termes IGN] image terrestre [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] lasergrammétrie [Termes IGN] semis de points [Termes IGN] sylviculture [Termes IGN] télémétrie laser terrestre Résumé : (Auteur) Terrestrial laser scanners find rapidly growing interest in photogrammetry as efficient tools for fast and reliable three-dimensional (3D) point cloud data acquisition. They have opened a wide range of application fields within a short period of time. Beyond interactive measurement in 3D point clouds, techniques for the automatic detection of objects and the determination of geometric parameters form a high priority research issue. With the quality of 3D point clouds generated by laser scanners and the automation potential in data processing, terrestrial laser scanning is also becoming a useful tool for forest inventory. This paper presents a brief review of current laser scanner systems from a technological point of view and discusses different scanner technologies and system parameters regarding their suitability for forestry applications. Methods for the automatic detection of trees in terrestrial laser scanner data as well as the automatic determination of diameter at breast height (DBH), tree height and 3D stem profiles are outlined. Reliability and precision of the techniques are analysed on the basis of several pilot studies. In these pilot studies more than 97% of the trees could be detected correctly, and DBH could be determined with a precision of about 1.8 cm. Copyright Taylor & Francis Numéro de notice : A2008-084 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736406 En ligne : https://doi.org/10.1080/01431160701736406 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29079 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-08031	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt