Centre de documentation
scientifique

Dépouillements

A semi-analytical model for multitemporal prediction of chlorophyll-a in an Iowa lake using Hyperion data / R. Sugumaran in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 12 (December 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 12 (December 2012) . - pp 1253 - 1260 Titre : A semi-analytical model for multitemporal prediction of chlorophyll-a in an Iowa lake using Hyperion data Type de document : Article/Communication Auteurs : R. Sugumaran, Auteur ; Jacques Thomas, Auteur Année de publication : 2012 Article en page(s) : pp 1253 - 1260 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse diachronique [Termes IGN] image EO1-Hyperion [Termes IGN] modèle de transfert radiatif [Termes IGN] prédiction [Termes IGN] qualité des eaux [Termes IGN] surveillance hydrologique [Termes IGN] système d'information géographique [Termes IGN] télédétection spatiale Résumé : (Auteur) The aim of this study was to use an analytical approach to monitor water quality in an Iowa lake using multitemporal Hyperion satellite imagery. Cloud-free hyperspectral images were acquired from the Hyperion sensor on individual days in June, July, and August of 2006. Water samples with accurate locations using GPS were collected simultaneously with image acquisition. Water samples were analyzed for various water quality constituents. Chlorophyll-a (chl), was estimated for each sampling date using a bio-optical model with Specific Inherent Optical Properties (siops) of the lake and light field variables derived from a radiative transfer numerical model. The model was then applied to the Hyperion images to create spatially continuous CHL maps for the study area every month. These results were compared with traditional linear regression model outputs. Maps produced using the bio-optical model effectively demonstrated spatial and temporal variability of CHL for the lake. The CHL concentration from this model across the lake ranged from 28 to 121ug/L for the month of June, 18 to 111ug/L for July, and 31 to 125 ug/L for August. The validation and accuracy assessment for the bio-optical model with in-situ data showed R2 values of 0.90978, 0.96794 and 0.93057 for June, July, and August, respectively, and Nash-Sutcliffe coefficient values of 0.499478, 0.733072, and 0.878757 for June, July, and August, respectively. Numéro de notice : A2012-644 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.78.11.1253 En ligne : https://doi.org/10.14358/PERS.78.11.1253 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32090 [article]

Automated delineation of individual tree crowns from lidar data by multi-scale analysis and segmentation / L. Jing in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 12 (December 2012)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 12 (December 2012) . - pp 1275 - 1284 Titre : Automated delineation of individual tree crowns from lidar data by multi-scale analysis and segmentation Type de document : Article/Communication Auteurs : L. Jing, Auteur ; B. Hu, Auteur ; J. Li, Auteur ; T. Noland, Auteur Année de publication : 2012 Article en page(s) : pp 1275 - 1284 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse multiéchelle [Termes IGN] arbre (flore) [Termes IGN] détection automatique [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] segmentation d'image Résumé : (Auteur) A canopy height model (chm) derived from lidar data can be segmented to obtain individual tree crowns. However, branches, tree crowns, and tree clusters usually have similar shapes and overlapping sizes. This causes current individual tree crown delineation methods for CHMs to work less effectively on closed canopy deciduous or mixed wood forests consisting of various-sized tree crowns. Based on mult-scale analysis and segmentation, an innovative tree crown delineation method was developed in this study. In this method, the scale levels of target tree crowns are first morphologically determined; the CHM is filtered at the multiple scale levels; and local maxima within each filtered CHM are taken as markers to segment the original chm using the marker-controlled watershed method. After tree crown segments are selected from the multiple resulting segmentation maps and integrated together, a complete tree crown map is generated. In an experiment on natural forests in Ontario, Canada, the proposed method yielded crown maps having a good consistency with manual and visual interpretation. For instance, when compared to a manually delineated forest map, the automated method correctly delineated about 69 percent, 65 percent, and 73 percent of the tree crowns from plots of closed canopy coniferous, deciduous, and mixed wood forests, respectively. Numéro de notice : A2012-645 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.78.11.1275 En ligne : https://doi.org/10.14358/PERS.78.11.1275 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32091 [article]