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Understanding the effects of ALS pulse density for metric retrieval across diverse forest types / Phil Wilkes in Photogrammetric Engineering & Remote Sensing, PERS, vol 81 n° 8 (August 2015)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 81 n° 8 (August 2015) . - pp 625 - 635 Titre : Understanding the effects of ALS pulse density for metric retrieval across diverse forest types Type de document : Article/Communication Auteurs : Phil Wilkes, Auteur ; Simon D. Jones, Auteur ; Lola Suarez, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 625 - 635 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] acquisition de données [Termes IGN] densité des points [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt tropicale [Termes IGN] hauteur des arbres [Termes IGN] image ALOS-PALSAR [Termes IGN] impulsion laser [Termes IGN] indicateur de gestion forestière durable [Termes IGN] rétrodiffusion [Termes IGN] savane [Termes IGN] télémétrie laser aéroporté Résumé : (auteur) Pulse density, the number of laser pulses that intercept a surface per unit area, is a key consideration when acquiring an Airborne Laser Scanning (ALS) dataset. This study compares area-based vegetation structure metrics derived from multireturn ALS simulated at six pulse densities (0.05 to 4 pl m-2) across a range of forest types: from savannah woodlands to dense rainforests. Results suggest that accurate measurement of structure metrics (canopy height, canopy cover, and vertical canopy structure) can be achieved with a pulse density of 0.5 pl m-2 across all forest types when compared to a dataset of 10 pl m-2. For pulse densities Numéro de notice : A2015-981 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.81.8.625 En ligne : https://doi.org/10.14358/PERS.81.8.625 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80252 [article]

An unsupervised urban change detection procedure by using luminance and saturation for multispectral remotely sensed images / Su Ye in Photogrammetric Engineering & Remote Sensing, PERS, vol 81 n° 8 (August 2015)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 81 n° 8 (August 2015) . - pp 637 - 645 Titre : An unsupervised urban change detection procedure by using luminance and saturation for multispectral remotely sensed images Type de document : Article/Communication Auteurs : Su Ye, Auteur ; Dongmei Chen, Auteur Année de publication : 2015 Article en page(s) : pp 637 - 645 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse comparative [Termes IGN] classification non dirigée [Termes IGN] détection de changement [Termes IGN] image multibande [Termes IGN] luminance lumineuse [Termes IGN] milieu urbain [Termes IGN] saturation de la couleur Résumé : (auteur) Unsupervised change detection techniques have been widely employed in the remote-sensing area when suitable reference data is not available. Image (or Index) differencing is one of the most commonly used methods due to its simplicity. However, past applications of image differencing were often inefficient in separating real change and noise due to the lack of steps for feature selection and integration of contextual information. To address these issues, we propose a novel unsupervised procedure which uses two complementary features, namely luminance and saturation, extracted from multispectral images, and combines T-point thresholding, Bayes fusion, and Markov Random Fields. Through a case study, the performance of our proposed procedure was compared with other three unsupervised changedetection methods including Principle Component Analysis (PCA), Fuzzy c-means (FCM), and Expectation Maximum-Markov Random Field (EM-MRF). The change detection results from our proposed method are more compact with less noise than those from other methods over urban areas. The quantitative accuracy assessment indicates that the overall accuracy and Kappa statistic of our proposed procedure are 95.1 percent and 83.3 percent, respectively, which are significantly higher than the other three unsupervised change detection methods Numéro de notice : A2015-982 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.81.8.637 En ligne : http://dx.doi.org/10.14358/PERS.81.8.637 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80253 [article]

Using international standards to control the positional quality of spatial data / Francisco Javier Ariza-López in Photogrammetric Engineering & Remote Sensing, PERS, vol 81 n° 8 (August 2015)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 81 n° 8 (August 2015) . - pp 657 - 668 Titre : Using international standards to control the positional quality of spatial data Type de document : Article/Communication Auteurs : Francisco Javier Ariza-López, Auteur ; José Avila-Rodriguez, Auteur Année de publication : 2015 Article en page(s) : pp 657 - 668 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Infrastructure de données [Termes IGN] contrôle qualité [Termes IGN] données localisées numériques [Termes IGN] erreur de positionnement [Termes IGN] norme de données localisées Résumé : (auteur) A positional quality control method based on the application of the International Standard ISO 2859 is proposed. This entails a common framework for dealing with the control of all other spatial data quality components (e.g., completeness, consistency, etc.). We propose a relationship between the parameters “acceptable quality level” and “limiting quality” of the international standard and positional quality by means of observed error models. This proposal does not require any assumption for positional errors (e.g., normality), which means that the application is universal. It can be applied to any type of positional and geometric controls (points, line-strings), to any dimension (1D, 2D, 3D, etc.) and with parametric or non-parametric error models (e.g., lidar). This paper introduces ISO 2859, presents the statistical bases of the proposal and develops two examples of application, the first dealing with a lot-by-lot control and the second, isolated lot control. Numéro de notice : A2015-983 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.14358/PERS.81.8.657 En ligne : https://doi.org/10.14358/PERS.81.8.657 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80254 [article]