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Backscatter coefficient as an attribute for the classification of full-waveform airborne laser scanning data in urban areas / C. Alexander in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 5 (September - October 2010)
[article]
Titre : Backscatter coefficient as an attribute for the classification of full-waveform airborne laser scanning data in urban areas Type de document : Article/Communication Auteurs : C. Alexander, Auteur ; Kevin Tansey, Auteur ; J. Kaduk, Auteur ; David A. Holland, Auteur ; Nicholas J. Tate, Auteur Année de publication : 2010 Article en page(s) : pp 423 - 432 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] angle d'incidence
[Termes IGN] classification dirigée
[Termes IGN] classification par arbre de décision
[Termes IGN] coefficient de rétrodiffusion
[Termes IGN] données laser
[Termes IGN] étalonnage de capteur (imagerie)
[Termes IGN] lidar à retour d'onde complète
[Termes IGN] milieu urbain
[Termes IGN] semis de points
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) Airborne laser scanning (ALS) data are increasingly being used for land cover classification. The amplitudes of echoes from targets, available from full-waveform ALS data, have been found to be useful in the classification of land cover. However, the amplitude of an echo is dependent on various factors such as the range and incidence angle, which makes it difficult to develop a classification method which can be applied to full-waveform ALS data from different sites, scanning geometries and sensors. Additional information available from full-waveform ALS data, such as range and echo width, can be used for radiometric calibration, and to derive backscatter cross section. The backscatter cross section of a target is the physical cross sectional area of an idealised isotropic target, which has the same intensity as the selected target. The backscatter coefficient is the backscatter cross section per unit area. In this study, the amplitude, backscatter cross section and backscatter coefficient of echoes from ALS point cloud data collected from two different sites are analysed based on urban land cover classes. The application of decision tree classifiers developed using data from the first study area on the second demonstrates the advantage of using the backscatter coefficient in classification methods, along with spatial attributes. It is shown that the accuracy of classification of the second study area using the backscatter coefficient (kappa coefficient 0.89) is higher than those using the amplitude (kappa coefficient 0.67) or backscatter cross section (kappa coefficient 0.68). This attribute is especially useful for separating road and grass. Numéro de notice : A2010-445 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.05.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.05.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30638
in ISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 423 - 432[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2010051 SL Revue Centre de documentation Revues en salle Disponible Influence of macroscale and microscale surface roughness on multi-beam RADARSAT-1 data: implications for geological mapping in the Curaçá Valley, Brazil / W.R. Paradella in Photo interprétation, European journal of applied remote sensing, vol 45 n° 2 (juin 2009)
[article]
Titre : Influence of macroscale and microscale surface roughness on multi-beam RADARSAT-1 data: implications for geological mapping in the Curaçá Valley, Brazil Type de document : Article/Communication Auteurs : W.R. Paradella, Auteur ; S. Knust, Auteur ; A. Dos Santos, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 51 - 61 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse en composantes principales
[Termes IGN] angle d'incidence
[Termes IGN] Brésil
[Termes IGN] carte géologique
[Termes IGN] géologie structurale
[Termes IGN] image Radarsat
[Termes IGN] niveau d'analyse
[Termes IGN] rugosité du sol
[Termes IGN] topographie locale
[Termes IGN] vallée
[Termes IGN] zone semi-arideRésumé : (Auteur) The dependence of the radar backscatter on macro and microtopography was examined through a collection of multi-beam RADARSAT-I imagery acquired under ascending and descending passes over the Curaça Valley, Northeastern Brazil. Firstly, the influence of both surface roughness regimes on the images was qualitatively evaluated through the use of Principal Component Analysis (PCA). The backscatter variability was emphasized using PCA since the components are linear combinations of all input radar target contributions within the original scenes. Secondly, the research addressed the quantitative influence of the microtopography on RADARSAT-1 Ó0 values through the use of statistical parameters derived from surface roughness profiles of distinct rock alteration products. The investigation has shown that the use of PCA on RADARSAT-1 imagery with distinct look-direction and incidence angles is a suitable technique for highlighting backscattering variability from distinct targets within each scene expressed by tonal and textural patterns. These image patterns reflected a combination of effects related to large-scale surface slope (scarps, crests, positive and negative topographic breaks, etc.) and to ground cover (surface roughness of rock outcrops, residual soils and vegetation cover). The topographic enhancement provided by the RADARSAT-1 PC2, PC3 and PC4 showed to be excellent for structural mapping. In addition, varia-tion in look-azimuth was more important than incidence changes in the enhancement of subtle geomorphic features, often an expression of geological structures and underlying lithology. Finally, the quantitative evaluation of the dependence of Ó0 on micro-scale surface roughness confirmed that the SAR backscattering was not controlled in a predominant manner by the microtopographic variations of the geological surfaces. Copyright Editions Eska Numéro de notice : A2009-522 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30151
in Photo interprétation, European journal of applied remote sensing > vol 45 n° 2 (juin 2009) . - pp 51 - 61[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 104-09021 SL Revue Centre de documentation Revues en salle Exclu du prêt Sea-surface polarization ratio from Envisat ASAR AP Data / H. Jonhsen in IEEE Transactions on geoscience and remote sensing, vol 46 n° 11 Tome 1 (November 2008)
[article]
Titre : Sea-surface polarization ratio from Envisat ASAR AP Data Type de document : Article/Communication Auteurs : H. Jonhsen, Auteur ; G. Engen, Auteur ; G. Guitton, Auteur Année de publication : 2008 Article en page(s) : pp 3637 - 3646 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] angle d'incidence
[Termes IGN] bande C
[Termes IGN] diffusométrie
[Termes IGN] image Envisat-ASAR
[Termes IGN] modèle de diffusion du rayonnement
[Termes IGN] polarimétrie radar
[Termes IGN] polarisation
[Termes IGN] surface de la mer
[Termes IGN] vent
[Termes IGN] vitesseRésumé : (Auteur) The polarization ratio (VV/HH) of normalized radar cross section over ocean surface is processed from Envisat advanced synthetic aperture radar (ASAR) alternating polarization (AP) data and compared with existing electromagnetic (EM) scattering models. The processing of the AP data is based on LevelO (raw data) product that enables us to accurately compute the contribution from additive noise separately from each burst. This is important in estimating the correct polarization ratio, particularly at higher incidence angles where the relative contribution from noise becomes severe. A recently published EM scattering model, general curvature method (GCM), is extended here to incorporate scattering from breaking waves. The performance of this model with and without breaking waves is compared with AP data and with other models for the polarization ratio. The extended GCM model is furthermore used to assess the performance of wind speed retrieval in HH polarization. The inclusion of wave breaking in the GCM model reduces the polarization ratio standard deviation from 0.64 to 0.50 and the bias from -0.34 to 0.16, as compared to the measured ASAR AP polarization ratio. The best semiempirical model from literature gives 0.51 and 0.63 for the standard deviation and bias, respectively. The difference in performance is shown to be caused by the wind speed dependence not accounted for in the semiempirical model. Validation of the new polarization ratio model in combination with C-band Model Function (CMOD) for wind speed retrieval at HH polarization shows similar performance as at VV polarization. We conclude that the GCM polarization ratio model incorporating wave-breaking effects is found to reproduce well polarization ratio measurements (ASAR AP) versus wind vector and incidence angle. Numéro de notice : A2008-537 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2008.2001061 En ligne : https://doi.org/10.1109/TGRS.2008.2001061 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29607
in IEEE Transactions on geoscience and remote sensing > vol 46 n° 11 Tome 1 (November 2008) . - pp 3637 - 3646[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-08111A RAB Revue Centre de documentation En réserve L003 Disponible Integration of multitemporal/polarization C-band SAR data sets for land-cover classification / N. Park in International Journal of Remote Sensing IJRS, vol 29 n° 15-16 (August 2008)
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Titre : Integration of multitemporal/polarization C-band SAR data sets for land-cover classification Type de document : Article/Communication Auteurs : N. Park, Auteur ; K.H. Chi, Auteur Année de publication : 2008 Article en page(s) : pp 4667 - 4688 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] analyse en composantes principales
[Termes IGN] angle d'incidence
[Termes IGN] bande C
[Termes IGN] carte agricole
[Termes IGN] image Envisat-ASAR
[Termes IGN] image radar
[Termes IGN] image Radarsat
[Termes IGN] intégration de données
[Termes IGN] occupation du sol
[Termes IGN] polarimétrie radarRésumé : (Auteur) This paper investigates the potential of multitemporal/polarization C-band SAR data for land-cover classification. Multitemporal Radarsat-1 data with HH polarization and ENVISAT ASAR data with VV polarization acquired in the Yedang plain, Korea are used for the classification of typical five land-cover classes in an agricultural area. The presented methodologies consist of two analytical stages: one for feature extraction and the other for classification based on the combination of features. Both a traditional SAR signal property analysis-based approach and principal-component analysis (PCA) are applied in the feature extraction stage. Special concerns are in the interpretation of each principal component by using principal-component loading. The tau model applied as a decision-level fusion methodology can provide a formal framework in which the posteriori probabilities derived from different sensor data can be combined. From the case study results, the combination of PCA-based features showed improved classification accuracy for both Radarsat-1 and ENVISAT ASAR data, as compared with the traditional SAR signal property analysis-based approach. The integration of PCA-based features based on multiple polarization (i.e. HH from Radarsat-1, and both VV and VH from ENVISAT ASAR) and different incidence angles contributed to a significant improvement of discrimination capability for dry fields which could not be properly classified by using only Radarsat-1 or ENVISAT ASAR data, and thus showed the best classification accuracy. The results of this case study indicate that the use of multiple polarization SAR data with a proper feature extraction stage would improve classification accuracy in multitemporal SAR data classification, although further consideration should be given to the polarization and incidence angle dependency of complex land-cover classes through more experiments. Numéro de notice : A2008-530 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160801947341 En ligne : https://doi.org/10.1080/01431160801947341 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29600
in International Journal of Remote Sensing IJRS > vol 29 n° 15-16 (August 2008) . - pp 4667 - 4688[article]Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning / F. Morsdorf in International Journal of Remote Sensing IJRS, vol 29 n° 5 (March 2008)
[article]
Titre : Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning Type de document : Article/Communication Auteurs : F. Morsdorf, Auteur ; O. Frey, Auteur ; E. Meier, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 1387 - 1406 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] altitude du capteur
[Termes IGN] angle d'incidence
[Termes IGN] angle de visée
[Termes IGN] couvert végétal
[Termes IGN] données laser
[Termes IGN] hauteur des arbres
[Termes IGN] instrumentation Toposys
[Termes IGN] Leaf Area Index
[Termes IGN] modèle numérique de terrain
[Termes IGN] parc naturel
[Termes IGN] plan de vol
[Termes IGN] signal laser
[Termes IGN] Suisse
[Termes IGN] télémétrie laser aéroportéRésumé : (Auteur) Airborne Laser Scanning (ALS) has been established as a valuable tool for the estimation of biophysical vegetation properties such as tree height, crown width, fractional cover and leaf area index (LAI). It is expected that the conditions of data acquisition, such as viewing geometry and sensor configuration influence the value of these parameters. In order to gain knowledge about these different conditions, we test for the sensitivity of vegetation products for viewing geometry, namely flying altitude and scanning (incidence) angle. Based on two methodologies for single tree extraction and derivation of fractional cover and LAI previously developed and published by our group, we evaluate how these variables change with either flying altitude or scanning angle. These are the two parameters which often need to be optimized towards the best compromise between point density and area covered with a single flight line, in order to reduce acquisition costs. Our test-site in the Swiss National Park was sampled with two nominal flying altitudes, 500 and 900 m above ground. Incidence angle and local incidence angle were computed based on the digital terrain model using a simple backward geocoding procedure. We divided the raw laser returns into several different incident angle classes based on the flight path data; the TopoSys Falcon II system used in this study has a maximum scan angle of + 7.15°. We compared the derived biophysical properties from each of these classes with field measurements based on tachymeter measurements and hemispherical photographs, which were geolocated using differential GPS. It was found that with increasing flying height the well-known underestimation of tree height increases. A similar behaviour can be observed for fractional cover; its respective values decrease with higher flying height. The minimum distance between first and last echo increases from 1.2 metres for 500 m AGL to more than 3 metres for 900 m AGL, which does alter return statistics. The behaviour for incidence angles is not so evident, probably due to the small scanning angle of the system used. fCover seems to be most affected by incidence angles, with significantly higher differences for locations further away from nadir. As expected, incidence angle appears to be of higher importance for vegetation density parameters than local incidence angle. Numéro de notice : A2008-081 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160701736349 En ligne : https://doi.org/10.1080/01431160701736349 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29076
in International Journal of Remote Sensing IJRS > vol 29 n° 5 (March 2008) . - pp 1387 - 1406[article]Exemplaires(1)
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