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Auteur F. Aguilar |
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Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesModelling vertical error in LiDAR-derived digital elevation models / F. Aguilar in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 1 (January - February 2010)
Titre : Modelling vertical error in LiDAR-derived digital elevation models Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; Jon Mills, Auteur ; J. Delgado, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 103 - 110 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] interpolation inversement proportionnelle à la distance
[Termes IGN] lasergrammétrie
[Termes IGN] modèle d'erreur
[Termes IGN] modèle numérique de surfaceRésumé : (Auteur) A hybrid theoretical–empirical model has been developed for modelling the error in LiDAR-derived digital elevation models (DEMs) of non-open terrain. The theoretical component seeks to model the propagation of the sample data error (SDE), i.e. the error from light detection and ranging (LiDAR) data capture of ground sampled points in open terrain, towards interpolated points. The interpolation methods used for infilling gaps may produce a non-negligible error that is referred to as gridding error. In this case, interpolation is performed using an inverse distance weighting (IDW) method with the local support of the five closest neighbours, although it would be possible to utilize other interpolation methods. The empirical component refers to what is known as “information loss”. This is the error purely due to modelling the continuous terrain surface from only a discrete number of points plus the error arising from the interpolation process. The SDE must be previously calculated from a suitable number of check points located in open terrain and assumes that the LiDAR point density was sufficiently high to neglect the gridding error. For model calibration, data for 29 study sites, 200*200 m in size, belonging to different areas around Almeria province, south-east Spain, were acquired by means of stereo photogrammetric methods. The developed methodology was validated against two different LiDAR datasets. The first dataset used was an Ordnance Survey (OS) LiDAR survey carried out over a region of Bristol in the UK. The second dataset was an area located at Gador mountain range, south of Almería province, Spain. Both terrain slope and sampling density were incorporated in the empirical component through the calibration phase, resulting in a very good agreement between predicted and observed data (R2=0.9856;p Numéro de notice : A2010-233 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2009.09.003 En ligne : https://doi.org/10.1016/j.isprsjprs.2009.09.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30427
in ISPRS Journal of photogrammetry and remote sensing > vol 65 n° 1 (January - February 2010) . - pp 103 - 110[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2010011 SL Revue Centre de documentation Revues en salle Disponible
Titre : Assessing geometric reliability of corrected images from very high resolution satellites Type de document : Article/Communication Auteurs : M. Aguilar, Auteur ; F. Aguilar, Auteur ; F. Aguera, Auteur Année de publication : 2008 Article en page(s) : pp 1551 - 1560 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] fiabilité des données
[Termes IGN] image à résolution métrique
[Termes IGN] image à résolution submétrique
[Termes IGN] image Ikonos
[Termes IGN] image panchromatique
[Termes IGN] image Quickbird
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] orthoimage
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] qualité géométrique (image)
[Termes IGN] valeur aberranteRésumé : (Auteur) Since the launch of Ikonos by Space Imaging, LLC on 24 September 1999, the very high resolution (VHR) satellite imagery has been applied to diverse fields. Every application needs a certain geometric accuracy in the corrected image; therefore, the planimetric accuracy control of VHR satellite imagery proves to be fundamental. As a rule of thumb, the Root Mean Square error (RMS) computed at independent check points (ICPs) is the global measure most widely used for accuracy assessment in VHR imagery. This paper presents an assessment, focused on two QuickBird and Ikonos panchromatic single images, of the number of ICPs required to obtain an estimation of one-dimensional accuracy (RMS1d) with a certain confidence level or reliability. Thus, two theoretical approaches have been tested to estimate reliability depending on the number of ICPs, and they have been experimentally validated using the Monte Carlo simulation method. The residual’s samples were generated for both satellite images in the best possible operational conditions: (a) using optimal sensor models, (b) with high accuracy ground points measured by Differential Global Positioning System, (c) with an adequate number of well distributed ground control points (GCPs), and (d) using GCPs and ICPs well-defined on the raw images, i.e., with a reasonably low pointing error. Under these conditions, the two theoretical models tested provided a good fit (r2 >97 percent) for the simulated data offered by Monte Carlo when outliers were withdrawn. There were no notable differences between the results obtained from the Ikonos and QuickBird scenes. Copyright ASPRS Numéro de notice : A2008-478 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.74.12.1551 En ligne : https://doi.org/10.14358/PERS.74.12.1551 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29547
in Photogrammetric Engineering & Remote Sensing, PERS > vol 74 n° 12 (December 2008) . - pp 1551 - 1560[article]
Titre : Using texture analysis to improve per-pixel classification of very high resolution images for mapping plastic greenhouses Type de document : Article/Communication Auteurs : F. Aguera, Auteur ; F. Aguilar, Auteur ; M. Aguilar, Auteur Année de publication : 2008 Article en page(s) : pp 635 - 646 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] agriculture
[Termes IGN] analyse comparative
[Termes IGN] carte thématique
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] image à très haute résolution
[Termes IGN] image Ikonos
[Termes IGN] image infrarouge couleur
[Termes IGN] image multibande
[Termes IGN] image Quickbird
[Termes IGN] image RVB
[Termes IGN] occupation du sol
[Termes IGN] précision de la classification
[Termes IGN] texture d'imageRésumé : (Auteur) The area occupied by plastic-covered greenhouses has undergone rapid growth in recent years, currently exceeding 500,000 ha worldwide. Due to the vast amount of input (water, fertilisers, fuel, etc.) required, and output of different agricultural wastes (vegetable, plastic, chemical, etc.), the environmental impact of this type of production system can be serious if not accompanied by sound and sustainable territorial planning. For this, the new generation of satellites which provide very high resolution imagery, such as QuickBird and IKONOS can be useful. In this study, one QuickBird and one IKONOS satellite image have been used to cover the same area under similar circumstances. The aim of this work was an exhaustive comparison of QuickBird vs. IKONOS images in land-cover detection. In terms of plastic greenhouse mapping, comparative tests were designed and implemented, each with separate objectives. Firstly, the Maximum Likelihood Classification (MLC) was applied using five different approaches combining R, G, B, NIR, and panchromatic bands. The combinations of the bands used, significantly influenced some of the indexes used to classify quality in this work. Furthermore, the quality classification of the QuickBird image was higher in all cases than that of the IKONOS image. Secondly, texture features derived from the panchromatic images at different window sizes and with different grey levels were added as a fifth band to the R, G, B, NIR images to carry out the MLC. The inclusion of texture information in the classification did not improve the classification quality. For classifications with texture information, the best accuracies were found in both images for mean and angular second moment texture parameters. The optimum window size in these texture parameters was 3*3 for IK images, while for QB images it depended on the quality index studied, but the optimum window size was around 15*15. With regard to the grey level, the optimum was 128. Thus, the optimum texture parameter depended on the main objective of the image classification. If the main classification goal is to minimize the number of pixels wrongly classified, the mean texture parameter should be used, whereas if the main classification goal is to minimize the unclassified pixels the angular second moment texture parameter should be used. On the whole, both QuickBird and IKONOS images offered promising results in classifying plastic greenhouses. Copyright ISPRS Numéro de notice : A2008-436 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2008.03.003 En ligne : https://doi.org/10.1016/j.isprsjprs.2008.03.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29505
in ISPRS Journal of photogrammetry and remote sensing > vol 63 n° 6 (November - December 2008) . - pp 635 - 646[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-08061 SL Revue Centre de documentation Revues en salle Disponible
Titre : Accuracy assessment of Lidar-derived digital elevation models Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; Jon P. Mills, Auteur Année de publication : 2008 Article en page(s) : pp 148 - 169 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse comparative
[Termes IGN] données lidar
[Termes IGN] erreur de mesure
[Termes IGN] lasergrammétrie
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle numérique de surface
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GPS
[Termes IGN] précision des mesuresRésumé : (Auteur) Despite the relatively high cost of airborne lidar-derived digital elevation models (DEMs), such products are usually presented without a satisfactory associated estimate of accuracy. For the most part, DEM accuracy estimates are typically provided by comparing lidar heights against a finite sample of check point coordinates from an independent source of higher accuracy, supposing a normal distribution of the derived height differences or errors. This paper proposes a new methodology to assess the vertical accuracy of lidar DEMs using confidence intervals constructed from a finite sample of errors computed at check points. A non-parametric approach has been tested where no particular error distribution is assumed, making the proposed methodology especially applicable to non-normal error distributions of the type usually found in DEMs derived from lidar. The performance of the proposed model was experimentally validated using Monte Carlo simulation on 18 vertical error data-sets. Fifteen of these data-sets were computed from original lidar data provided by the International Society for Photogrammetry and Remote Sensing Working Group III/3, using their respective filtered reference data as ground truth. The three remaining data-sets were provided by the Natural Environment Research Council's Airborne Research and Survey Facility lidar system, together with check points acquired using high precision kinematic GPS. The results proved promising, the proposed models reproducing the statistical behaviour of vertical errors of lidar using a favourable number of check points, even in the cases of data-sets with non-normally distributed residuals. This research can therefore be considered as a potentially important step towards improving the quality control of lidar-derived DEMs. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2008-295 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2008.00476.x En ligne : https://doi.org/10.1111/j.1477-9730.2008.00476.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29288
in Photogrammetric record > vol 23 n° 122 (June - August 2008) . - pp 148 - 169[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 106-08021 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : Geometric accuracy assessment of QuickBird basic imagery using different operational approaches Type de document : Article/Communication Auteurs : M. Aguilar, Auteur ; F. Aguilar, Auteur ; F. Aguera, Auteur ; Jaime Sanchez, Auteur Année de publication : 2007 Article en page(s) : pp 1321 - 1332 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] analyse comparative
[Termes IGN] correction géométrique
[Termes IGN] données localisées 3D
[Termes IGN] erreur moyenne quadratique
[Termes IGN] image à très haute résolution
[Termes IGN] image Quickbird
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle par fonctions rationnelles
[Termes IGN] modèle physique
[Termes IGN] orientation du capteur
[Termes IGN] orthoimage
[Termes IGN] point d'appui
[Termes IGN] précision géométrique (imagerie)Résumé : (Auteur) The new very high-resolution space satellite images, such as QuickBird and Ikonos, open new possibilities in cartographic applications. This work has as its main aim the assessment of a methodology to achieve the best possible geometric accuracy in orthorectified imagery products obtained from QuickBird basic imagery which will include an assessment of the methodology’s reliability. Root Mean Square Error (RMSE), mean error or bias, and maximum error in 79 independent check points are computed and utilized as accuracy indicators. The ancillary data were generated by high accuracy methods: (a) check and control points were measured with a differential global positioning system, and (b) a dense digital elevation model (DEM) with grid spacing of 2 m and RMSEz of about 0.31 m generated from a photogrammetric aerial flight at an approximate scale of 1:5000 that was used for image orthorectification. Two other DEMs with a grid spacing of 5 m (RMSEz = 1.75 m) and 20 m (RMSEz = 5.82 m) were also used. Four 3D geometric correction models were used to correct the satellite data: two terrain-independent rational function models refined by the user, a terrain-dependent model, and a rigorous physical model. The number and distribution of the ground control points (GCPs) used for the sensor orientation were studied as well, testing from 9 to 45 GCPs. The best results obtained about the geometric accuracy of the orthorectified images (two dimensional RMSE of about 0.74 m) were computed when the dense DEM was used with the 3D physical and terrain-dependent models. The use of more than 18 GCPs does not improve the results when those GCPs are extracted by stratified random sampling. Copyright ASPRS Numéro de notice : A2007-541 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.12.1321 En ligne : http://dx.doi.org/10.14358/PERS.73.12.1321 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28904
in Photogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 12 (December 2007) . - pp 1321 - 1332[article]
