Photogrammetric Engineering & Remote Sensing, PERS / American society for photogrammetry and remote sensing . vol 72 n° 12Mention de date : December 2006 Paru le : 01/12/2006 ISBN/ISSN/EAN : 0099-1112 |
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Ajouter le résultat dans votre panierChange 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)
[article]
Titre : Change detection techniques for canopy height growth measurements using airborne laser scanner data Type de document : Article/Communication Auteurs : X. Yu, Auteur ; Juha Hyyppä, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 1339 - 1348 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse diachronique
[Termes IGN] détection de changement
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] forêt boréale
[Termes IGN] hauteur des arbres
[Termes IGN] houppier
[Termes IGN] instrumentation Toposys
[Termes IGN] modèle numérique de surface
[Termes IGN] objet géographique ponctuel
[Termes IGN] Pinus sylvestris
[Termes IGN] semis de pointsRésumé : (Auteur) This paper analyzes the potential of airborne laser scanner data for measuring individual tree height growth in a boreal forest using 82 sample trees of Scots pine. Point clouds (10 points/m2, beam size 40 cm) illuminating 50 percent of the treetops were acquired in September 1998 and May 2003 with the Toposys 83 kHz lidar system. The reference height and height growth of pines were measured with a tacheometer in the field. Three different types of features were extracted from the point clouds representing each tree; they were the difference between the highest z values, the difference between the DSMs of the tree crown, and the differences between the 85th, 90th and 95th percentiles of the canopy height histograms corresponding to the crown. The best correspondence with the field measurements was achieved with an R2 value of 0.68 and a RMSE of 43 cm. The results indicate that it is possible to measure the growth of an individual tree with multi-temporal laser surveys. We also demonstrated a new algorithm for tree-to-tree matching. It is needed in operational growth estimation based on individual trees, especially in dense spruce forests. The method is based on minimizing the distances between treetops in the N- dimensional data space. The experiments showed that the use of the location (derived from laser data) and height of the trees were together adequate to provide reliable tree-to-tree matching. In the future, a fourth dimension (the crown area) should also be included in the matching. Copyright ASPRS Numéro de notice : A2006-543 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.72.12.1339 En ligne : https://doi.org/10.14358/PERS.72.12.1339 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28266
in Photogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 12 (December 2006) . - pp 1339 - 1348[article]Examining the influence of changing laser pulse repetition frequencies on conifer forest canopy returns / Laura Chasmer in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 12 (December 2006)
[article]
Titre : Examining the influence of changing laser pulse repetition frequencies on conifer forest canopy returns Type de document : Article/Communication Auteurs : Laura Chasmer, Auteur ; Christopher Hopkinson, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 1359 - 1367 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] ALTM
[Termes IGN] canopée
[Termes IGN] données lidar
[Termes IGN] données multitemporelles
[Termes IGN] forêt boréale
[Termes IGN] fréquence
[Termes IGN] impulsion laser
[Termes IGN] lasergrammétrie
[Termes IGN] onde radioélectrique
[Termes IGN] Pinophyta
[Termes IGN] surface du sol
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] vibrationRésumé : (Auteur) The distribution of laser pulses within conifer forest trees and canopies are examined by varying the rate of laser pulse emission and the inherent laser pulse properties (laser pulse energy, pulse width, pulse length, and roll-over or trigger time). In this study, an Optech, Inc. ALTM 3100 airborne lidar is used, emitting pulses at 50 kHz and 100 kHz, allowing for changes in laser pulse characteristics while also keeping all other survey parameters equal. We found that:
1. Pulses and associated characteristics emitted at 50 kHz penetrated further into the canopy than 100 kHz for a significant number of individual trees.
2. At tall tree plots with no understory, pulses emitted at 50 kHz penetrated further into the canopy than 100 kHz for a significant number of plots.
3. For plots with significant understory and shorter trees, pulses emitted at 100 kHz penetrated further into the canopy than 50 kHz. We suspect that this may be due, in part, to canopy openness.
Laser pulse energy and character differences associated with different laser pulse emission frequencies are likely a contributing factor in laser pulse penetration through the canopy to the ground surface. Efforts to understand laser pulse character influences on canopy returns are important as biomass and vegetation structure models derived from lidar are increasingly adopted. Copyright ASPRSNuméro de notice : A2006-544 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.72.12.1359 En ligne : https://doi.org/10.14358/PERS.72.12.1359 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28267
in Photogrammetric Engineering & Remote Sensing, PERS > vol 72 n° 12 (December 2006) . - pp 1359 - 1367[article]