Centre de documentation
scientifique

Assessing geometric reliability of corrected images from very high resolution satellites / M. Aguilar in Photogrammetric Engineering & Remote Sensing, PERS, vol 74 n° 12 (December 2008)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 74 n° 12 (December 2008) . - pp 1551 - 1560 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 aberrante Résumé : (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 [article]

Using texture analysis to improve per-pixel classification of very high resolution images for mapping plastic greenhouses / F. Aguera in ISPRS Journal of photogrammetry and remote sensing, vol 63 n° 6 (November - December 2008)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 63 n° 6 (November - December 2008) . - pp 635 - 646 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'image Résumé : (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 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-08061	SL	Revue	Centre de documentation	Revues en salle	Disponible

Geometric accuracy assessment of QuickBird basic imagery using different operational approaches / M. Aguilar in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 12 (December 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 12 (December 2007) . - pp 1321 - 1332 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 [article]

A theoretical approach to modeling the accuracy assessment of digital elevation models / F. Aguilar in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 12 (December 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 12 (December 2007) . - pp 1367 - 1379 Titre : A theoretical approach to modeling the accuracy assessment of digital elevation models Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; F. Aguera, Auteur ; M. Aguilar, Auteur Année de publication : 2007 Article en page(s) : pp 1367 - 1379 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] erreur moyenne quadratique [Termes IGN] fiabilité des données [Termes IGN] fonction de base radiale [Termes IGN] interpolation inversement proportionnelle à la distance [Termes IGN] méthode de Monte-Carlo [Termes IGN] modèle numérique de surface [Termes IGN] précision des données [Termes IGN] résidu Résumé : (Auteur) In this paper, a theoretical analysis is presented of the degree of correctness to which the accuracy figures of a grid Digital Elevation Model (DEM) have been estimated, measured as Root Mean Square Error (RMSE) depending on the number of checkpoints used in the accuracy assessment process. The latter concept is sometimes referred to as the Reliability of the DEM accuracy tests. Two theoretical models have been developed for estimating the reliability of the DEM accuracy figures using the number of checkpoints and parameters related to the statistical distribution of residuals (mean, variance, skewness, and standardized kurtosis). A general case was considered in which residuals might be weakly correlated (local spatial autocorrelation) with non-zero mean and non-normal distribution. Thus, we avoided the “strong assumption” of distribution normality accepted in some of the previous works and in the majority of the current standards of positional accuracy control methods. Sampled data were collected using digital photogrammetric methods applied to large scale stereo imagery (1:5 000). In this way, seven morphologies were sampled with a 2 m by 2 m sampling interval, ranging from flat (3 percent average slope) to the highly rugged terrain of marble quarries (82 percent average slope). Two local schemes of interpolation have been employed, using Multiquadric Radial Basis Functions (MRBF) and Inverse Distance Weighted (IDW) interpolators, to generate interpolated surfaces from high-resolution grid DEMs. The theoretical results obtained were experimentally validated using the Monte Carlo simulation method. The proposed models provided a good fit for the raw simulated data for the seven morphologies and the two schemes of interpolation tested (r2 > 0.96 as mean value). The proposed theoretical models performed very well for modeling the non-gaussian distribution of the errors at the checkpoints, a property which is very common in geographically distributed data. Copyright ASPRS Numéro de notice : A2007-542 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.12.1367 En ligne : https://doi.org/10.14358/PERS.73.12.1367 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28905 [article]

Accuracy assessment of digital elevation models using a non-parametric approach / F. Aguilar in International journal of geographical information science IJGIS, vol 21 n° 6-7 (july 2007)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 21 n° 6-7 (july 2007) . - pp 667 - 686 Titre : Accuracy assessment of digital elevation models using a non-parametric approach Type de document : Article/Communication Auteurs : F. Aguilar, Auteur ; M. Aguilar, Auteur ; F. Aguera, Auteur Année de publication : 2007 Article en page(s) : pp 667 - 686 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] données localisées [Termes IGN] estimation statistique [Termes IGN] méthode de Monte-Carlo [Termes IGN] modèle numérique de surface [Termes IGN] qualité des données [Termes IGN] résidu Résumé : (Auteur) This paper explores three theoretical approaches for estimating the degree of correctness to which the accuracy figures of a gridded Digital Elevation Model (DEM) have been estimated depending on the number of checkpoints involved in the assessment process. The widely used average-error statistic Mean Square Error (MSE) was selected for measuring the DEM accuracy. The work was focused on DEM uncertainty assessment using approximate confidence intervals. Those confidence intervals were constructed both from classical methods which assume a normal distribution of the error and from a new method based on a non-parametric approach. The first two approaches studied, called Chi-squared and Asymptotic Student t, consider a normal distribution of the residuals. That is especially true in the first case. The second case, due to the asymptotic properties of the t distribution, can perform reasonably well with even slightly non-normal residuals if the sample size is large enough. The third approach developed in this article is a new method based on the theory of estimating functions which could be considered much more general than the previous two cases. It is based on a non-parametric approach where no particular distribution is assumed. Thus, we can avoid the strong assumption of distribution normality accepted in previous work and in the majority of current standards of positional accuracy. The three approaches were tested using Monte Carlo simulation for several populations of residuals generated from originally sampled data. Those original grid DEMs, considered as ground data, were collected by means of digital photogrammetric methods from seven areas displaying differing morphology employing a 2 by 2 m sampling interval. The original grid DEMs were subsampled to generate new lower-resolution DEMs. Each of these new DEMs was then interpolated to retrieve its original resolution using two different procedures. Height differences between original and interpolated grid DEMs were calculated to obtain residual populations. One interpolation procedure resulted in slightly non-normal residual populations, whereas the other produced very non-normal residuals with frequent outliers. Monte Carlo simulations allow us to report that the estimating function approach was the most robust and general of those tested. In fact, the other two approaches, especially the Chi-squared method, were clearly affected by the degree of normality of the residual population distribution, producing less reliable results than the estimating functions approach. This last method shows good results when applied to the different datasets, even in the case of more leptokurtic populations. In the worst cases, no more than 64-128 checkpoints were required to construct an estimate of the global error of the DEM with 95% confidence. The approach therefore is an important step towards saving time and money in the evaluation of DEM accuracy using a single average-error statistic. Nevertheless, we must take into account that MSE is essentially a single global measure of deviations, and thus incapable of characterizing the spatial variations of errors over the interpolated surface. Copyright Taylor & Francis Numéro de notice : A2007-265 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/13658810601079783 En ligne : https://doi.org/10.1080/13658810601079783 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28628 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-07041	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-07042	RAB	Revue	Centre de documentation	En réserve L003	Disponible

An integrated model to estimate the accuracy of digital orthoimages from high resolution satellite imagery / F. Aguilar in Revue Française de Photogrammétrie et de Télédétection, n° 184 (Décembre 2006)  

Permalink

The accuracy of grid digital elevation models linearly constructed from scattered sample data / F. Aguilar in International journal of geographical information science IJGIS, vol 20 n° 2 (february 2006)  

Permalink