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Auteur F. Morsdorf |
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Fusion of imaging spectroscopy and airborne laser scanning data for characterization of forest ecosystems – A review / Hossein Torabzadeh in ISPRS Journal of photogrammetry and remote sensing, vol 97 (November 2014)
[article]
Titre : Fusion of imaging spectroscopy and airborne laser scanning data for characterization of forest ecosystems – A review Type de document : Article/Communication Auteurs : Hossein Torabzadeh, Auteur ; F. Morsdorf, Auteur ; Michael E. Schaepman, Auteur Année de publication : 2014 Article en page(s) : pp 25 – 35 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] écosystème forestier
[Termes IGN] fusion d'images
[Termes IGN] modèle empirique
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) Forest ecosystems play an important role in the global carbon cycle and it is largely unknown how this role might be altered by transients imposed by global change and deforestation. Remote sensing can provide information on ecosystem state and functioning and, among others, two remote sensing techniques, airborne laser scanning (ALS) and imaging spectroscopy (IS), have been used to characterize forest ecosystems, both independently and combined in fusion approaches. However, the fusion of these datasets should make the best use of the complementarity of both sensors and provide better and more robust vegetation products in forested ecosystems. Similar to other data fusion approaches, satisfying results depend on choosing appropriate fusion levels and methods. In this review paper, we summarize and classify relevant studies that focused on forest characterization using combined ALS and IS data, limited to the last decade. We classified the approaches by fusion level (data or product level) and by choice of methods (physical or empirical methods). Five different categories of products (landcover maps, aboveground biomass, biophysical parameters, gross/net primary productivity and biochemical parameters), have been found as the main aspects of forest ecosystems studied so far. A qualitative accuracy analysis of the products exposed that currently landcover maps are profiting the most from ALS and IS data fusion, while there is room for improvements in respect to the other products, such as biophysical parameters. Only few studies using physical approaches were found, but we expect the use of such approaches will increase with the growing availability of physically based radiative transfer models that can simulate both, ALS and IS data. Numéro de notice : A2014-523 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2014.08.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2014.08.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74135
in ISPRS Journal of photogrammetry and remote sensing > vol 97 (November 2014) . - pp 25 – 35[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2014111 RAB Revue Centre de documentation En réserve L003 Disponible 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)
[article]
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 aéroportéRésumé : (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
in International Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1387 - 1406[article]Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 080-08031 RAB Revue Centre de documentation En réserve L003 Exclu du prêt LIDAR-based geometric reconstruction of boreal type forest stands at single tree level for forest and wildland fire management / F. Morsdorf in Remote sensing of environment, vol 92 n° 3 (30 August 2004)
[article]
Titre : LIDAR-based geometric reconstruction of boreal type forest stands at single tree level for forest and wildland fire management Type de document : Article/Communication Auteurs : F. Morsdorf, Auteur ; E. Meier, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 353 - 362 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] forêt boréale
[Termes IGN] hauteur des arbres
[Termes IGN] houppier
[Termes IGN] incendie de forêt
[Termes IGN] lasergrammétrie
[Termes IGN] lutte contre l'incendie
[Termes IGN] reconstruction 3D
[Termes IGN] risque naturel
[Termes IGN] segmentation d'image
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) Vegetation structure is an important parameter in fire risk assessment and fire behavior modeling. We present a new approach deriving the structure of the upper canopy by segmenting single trees from small footprint LIDAR data and deducing their geometric properties. The accuracy LIDAR data is evaluated using six geometric reference targets, with the standard deviation of the LIDAR returns on the target being as low as 0.06 m. The segmentation is carried out by using cluster analysis on the LIDAR raw data in all three coordinate dimensions. From the segmented clusters, tree position, tree height, and crown diameter are derived and compared with field measurements. A robust linear regression of 917 tree height measurements yields a slope of 0.96 with an offset of 1 m and the adjusted R 2 resulting at 0.92. However, crown diameter is not well matched by the field measurements, with R2 being as low as 0.2, which is most certainly due to random errors in the field measurements. Finally, a geometric reconstruction of the forest scene using a paraboloid model is carried out using values of tree positsion, tree height, crown diameter, and crown base height.
Copyright ElsevierNuméro de notice : A2004-384 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.05.013 En ligne : https://doi.org/10.1016/j.rse.2004.05.013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26911
in Remote sensing of environment > vol 92 n° 3 (30 August 2004) . - pp 353 - 362[article]