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Auteur Richard A. Fournier |
Documents disponibles écrits par cet auteur
Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesComparison of three algorithms to estimate tree stem diameter from terrestrial laser scanner data / Joris Ravaglia in Forests, vol 10 n° 7 (July 2019)
Titre : Comparison of three algorithms to estimate tree stem diameter from terrestrial laser scanner data Type de document : Article/Communication Auteurs : Joris Ravaglia, Auteur ; Richard A. Fournier, Auteur ; Alexandra Bac, Auteur ; Cédric Vega Année de publication : 2019 Projets : ARBRE / AgroParisTech Article en page(s) : 19 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse comparative
[Termes IGN] Canada
[Termes IGN] diamètre à hauteur de poitrine
[Termes IGN] diamètre des arbres
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] feuillu
[Termes IGN] France (administrative)
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] Pinophyta
[Termes IGN] semis de points
[Termes IGN] transformation de Hough
[Termes IGN] volume en boisRésumé : (auteur) Terrestrial laser scanners provide accurate and detailed point clouds of forest plots, which can be used as an alternative to destructive measurements during forest inventories. Various specialized algorithms have been developed to provide automatic and objective estimates of forest attributes from point clouds. The STEP (Snakes for Tuboid Extraction from Point cloud) algorithm was developed to estimate both stem diameter at breast height and stem diameters along the bole length. Here, we evaluate the accuracy of this algorithm and compare its performance with two other state-of-the-art algorithms that were designed for the same purpose (i.e., the CompuTree and SimpleTree algorithms). We tested each algorithm against point clouds that incorporated various degrees of noise and occlusion. We applied these algorithms to three contrasting test sites: (1) simulated scenes of coniferous stands in Newfoundland (Canada), (2) test sites of deciduous stands in Phalsbourg (France), and (3) coniferous plantations in Quebec, Canada. In most cases, the STEP algorithm predicted diameter at breast height with higher R2 and lower RMSE than the other two algorithms. The STEP algorithm also achieved greater accuracy when estimating stem diameter in occluded and noisy point clouds, with mean errors in the range of 1.1 cm to 2.28 cm. The CompuTree and SimpleTree algorithms respectively produced errors in the range of 2.62 cm to 6.1 cm and 1.03 cm to 3.34 cm, respectively. Unlike CompuTree or SimpleTree, the STEP algorithm was not able to estimate trunk diameter in the uppermost portions of the trees. Our results show that the STEP algorithm is more adapted to extract DBH and stem diameter automatically from occluded and noisy point clouds. Our study also highlights that SimpleTree and CompuTree require data filtering and results corrections. Conversely, none of these procedures were applied for the implementation of the STEP algorithm. Numéro de notice : A2019-337 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/f10070599 date de publication en ligne : 18/07/2019 En ligne : https://doi.org/10.3390/f10070599 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93367
in Forests > vol 10 n° 7 (July 2019) . - 19 p.[article]
Titre : Analyzing the vertical distribution of crown material in mixed stand composed of two temperate tree species Type de document : Article/Communication Auteurs : Olivier Martin-Ducup, Auteur ; Robert Schneider, Auteur ; Richard A. Fournier, Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Abies balsamea
[Termes IGN] acer saccharum
[Termes IGN] densité du feuillage
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] écologie forestière
[Termes IGN] feuille (végétation)
[Termes IGN] houppier
[Termes IGN] voxelRésumé : (Auteur) The material distribution inside tree crowns is difficult to quantify even though it is an important variable in forest management and ecology. The vertical distribution of a relative density index (i.e., vertical profile) of the total, woody, and leafy material at the crown scale were estimated from terrestrial laser scanner (TLS) data on two species, sugar maple (Acer saccharum Marsh.) and balsam fir (Abies Balsamea Mill.). An algorithm based on a geometrical approach readily available in the Computree open source platform was used. Beta distributions were then fitted to the vertical profiles and compared to each other. Total and leafy profiles had similar shapes, while woody profiles were different. Thus, the total vertical distribution could be a good proxy for the leaf distribution in the crown. Sugar maple and balsam fir had top heavy and bottom heavy distributions respectively, which can be explained by their respective architectural development. Moreover, the foliage distribution of sugar maples shifted towards the crown base when it was found in mixed stands, when compared to pure stands. The opposite behavior was observed for balsam firs, but less pronounced. According to the shape of the foliage distribution, sugar maple takes advantages from mixture contrarily to balsam fir. From a methodological point of view, we proposed an original approach to separate wood from leaf returns in TLS data while taking into account occlusion. Wood and leaf separation and occlusion problems are two challenging issues for most TLS-based studies in forest ecology. Numéro de notice : A2018-487 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/f9110673 date de publication en ligne : 26/10/2018 En ligne : https://doi.org/10.3390/f9110673 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91223
in Forests > vol 9 n° 11 (November 2018)[article]
Titre : Preface for the SilviLaser 2015 special section Type de document : Article/Communication Auteurs : Sylvie Durrieu, Auteur ; Cédric Vega Congrès : Silvilaser 2015, 14th conference on Lidar Applications for Assessing and Managing Forest Ecosystems (28 - 30 septembre 2015; La Grande Motte, France) Année de publication : 2017 Article en page(s) : pp 412 - 413 Langues : Anglais (eng) Numéro de notice : A2017-886 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtSansCL DOI : 10.1016/j.rse.2017.03.018 date de publication en ligne : 23/03/2017 En ligne : https://doi.org/10.1016/j.rse.2017.03.018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91863
in Remote sensing of environment > vol 194 (June 2017) . - pp 412 - 413[article]vol 29 n° 3 - 01/06/2003 - Lidar (Bulletin de Canadian journal of remote sensing) / Richard A. Fournier
Titre : vol 29 n° 3 - 01/06/2003 - Lidar Type de document : Périodique Auteurs : Richard A. Fournier, Editeur scientifique ; Canadian remote sensing society, Auteur Année de publication : 2003 Langues : Anglais (eng) Français (fre) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] LidarNuméro de notice : 117-0303 Thématique : IMAGERIE Nature : Numéro de périodique Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=5019 [n° ou bulletin]Réservation
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