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The influence of scanner parameters on the extraction of tree metrics from FARO Photon 120 terrestrial laser scans / Pyare Pueschel in ISPRS Journal of photogrammetry and remote sensing, vol 78 (April 2013)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 78 (April 2013) . - pp 58 - 68 Titre : The influence of scanner parameters on the extraction of tree metrics from FARO Photon 120 terrestrial laser scans Type de document : Article/Communication Auteurs : Pyare Pueschel, Auteur Année de publication : 2013 Article en page(s) : pp 58 - 68 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre (flore) [Termes IGN] extraction de la végétation [Termes IGN] télémètre laser terrestre [Termes IGN] tronc Résumé : (Auteur) In the present study the influence of the scanner parameters, scan resolution (angular step size), scan speed (number of laser pulses per second), and pulse duration, on tree stem detection, stem diameter and volume extraction from phase-shift FARO Photon 120 TLS data was assessed. Additionally the effects of a data post processing (filtering of raw scan data) were investigated. All analyses were carried out based on single and merged scan data. It could be shown that scan speed, pulse duration and data filtering only marginally affect stem detection rates and stem diameter and volume estimation accuracies. By contrast scan resolution was found to have an effect, the magnitude of which, however, is range-dependent. For example mean stem detection rates for the three different scan resolutions tested were found to be equal in near range, but decreased more strongly for the lower scan resolutions in far range. With regard to the stem diameter extraction, scan resolution did not affect stem diameter at breast height (DBH) estimation accuracy, but limited the range within which DBH could be reliably extracted. The root mean squared error (RMSE) for DBH extracted from the single scan data was found to be significantly larger compared to the RMSE for DBH extracted from the merged scan data. Single scan data yielded stem volume estimates with lower accuracies, too. This study demonstrated that it is possible to maximize sampling efficiency by using scanner parameter sets with low scanning times (i.e., low scan resolution, high scan speed) without significantly losing estimation accuracy. If maximum accuracy is desired for both DBH and stem volume, the acquisition of multiple scans with a subsequent data merging is required. Numéro de notice : A2013-179 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.01.005 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.01.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32317 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2013041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

The influence of scan mode and circle fitting on tree stem detection, stem diameter and volume extraction from terrestrial laser scans / Pyare Pueschel in ISPRS Journal of photogrammetry and remote sensing, vol 77 (March 2013)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 77 (March 2013) . - pp 44 - 56 Titre : The influence of scan mode and circle fitting on tree stem detection, stem diameter and volume extraction from terrestrial laser scans Type de document : Article/Communication Auteurs : Pyare Pueschel, Auteur ; Glenn J. Newnham, Auteur ; Gilles Rock, Auteur ; Thomas Udelhoven, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 44 - 56 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection automatique [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] Pseudotsuga menziesii [Termes IGN] semis de points [Termes IGN] tronc [Termes IGN] volume (grandeur) Résumé : (Auteur) Terrestrial laser scanning (TLS) has been used to estimate a number of biophysical and structural vegetation parameters. Of these stem diameter is a primary input to traditional forest inventory. While many experimental studies have confirmed the potential for TLS to successfully extract stem diameter, the estimation accuracies differ strongly for these studies – due to differences in experimental design, data processing and test plot characteristics. In order to provide consistency and maximize estimation accuracy, a systematic study into the impact of these variables is required. To contribute to such an approach, 12 scans were acquired with a FARO photon 120 at two test plots (Beech, Douglas fir) to assess the effects of scan mode and circle fitting on the extraction of stem diameter and volume. An automated tree stem detection algorithm based on the range images of single scans was developed and applied to the data. Extraction of stem diameter was achieved by slicing the point cloud and fitting circles to the slices using three different algorithms (Lemen, Pratt and Taubin), resulting in diameter profiles for each detected tree. Diameter at breast height (DBH) was determined using both the single value for the diameter fitted at the nominal breast height and by a linear fit of the stem diameter vertical profile. The latter is intended to reduce the influence of outliers and errors in the ground level determination. TLS-extracted DBH was compared to tape-measured DBH. Results show that tree stems with an unobstructed view to the scanner can be successfully extracted automatically from range images of the TLS data with detection rates of 94% for Beech and 96% for Douglas fir. If occlusion of trees is accounted for stem detection rates decrease to 85% (Beech) and 84% (Douglas fir). As far as the DBH estimation is concerned, both DBH extraction methods yield estimates which agree with reference measurements, however, the linear fit based approach proved to be more robust for the single scan DBH extraction (RMSE range 1.39–1.74 cm compared to 1.47–2.43 cm). With regard to the different circle fit algorithms applied, the algorithm by Lemen showed the best overall performance (RMSE range 1.39–1.65 cm compared to 1.49–2.43 cm). The Lemen algorithm was also found to be more robust in case of noisy data. Compared to the single scans, the DBH extraction from the merged scan data proved to be superior with significant lower RMSE’s (0.66–1.21 cm). The influence of scan mode and circle fitting is reflected in the stem volume estimates, too. Stem volumes extracted from the single scans exhibit a large variability with deviations from the reference volumes ranging from -34% to 44%. By contrast volumes extracted from the merged scans only vary weakly (-2% to 6%) and show a marginal influence of circle fitting. Numéro de notice : A2013-114 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2012.12.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.12.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32252 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2013031	RAB	Revue	Centre de documentation	En réserve L003	Disponible