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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)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 423 - 432 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 aéroporté Résumé : (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 [article]

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Photogrammetric modeling of underwater environments / G. Telem in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 5 (September - October 2010)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 433 - 444 Titre : Photogrammetric modeling of underwater environments Type de document : Article/Communication Auteurs : G. Telem, Auteur ; S. Filin, Auteur Année de publication : 2010 Article en page(s) : pp 433 - 444 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] correction géométrique [Termes IGN] distorsion d'image [Termes IGN] étalonnage de chambre métrique [Termes IGN] modèle géométrique de prise de vue [Termes IGN] photogrammétrie sous-marine [Termes IGN] réfraction de l'eau Résumé : (Auteur) Underwater photogrammetry provides an efficient nondestructive means for measurement in environments with limited accessibility. With the growing use of consumer cameras, its application is becoming easier, thus benefiting a wide variety of disciplines. However, utilizing cameras for underwater photogrammetry poses some nontrivial modeling problems due to refraction effect and the extension of the imaging system into a unit of both the camera and the protecting housing device. This paper studies the effect that the underwater environment has on the photogrammetric process, and proposes a model for describing the geometric distortions and for estimating the additional parameters involved. The proposed model accounts not only for the multimedia effect, but also for inaccuracies related to the setting of the camera and housing device. The paper shows that only a small number of additional parameters is needed to model both elements and to preserve the collinearity relation. The results show that no unique setup is needed for estimating the additional parameters and that the estimation is insensitive to noise or first approximations. Experiments show that high levels of accuracy can be achieved. Numéro de notice : A2010-446 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.05.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.05.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30639 [article]

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A unified approach to self-calibration of terrestrial laser scanners / Yuriy Reshetyuk in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 5 (September - October 2010)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 445 - 456 Titre : A unified approach to self-calibration of terrestrial laser scanners Type de document : Article/Communication Auteurs : Yuriy Reshetyuk, Auteur Année de publication : 2010 Article en page(s) : pp 445 - 456 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] auto-étalonnage [Termes IGN] compensation par moindres carrés [Termes IGN] corrélation automatique de points homologues [Termes IGN] erreur systématique [Termes IGN] étalonnage d'instrument [Termes IGN] instrumentation Leica [Termes IGN] semis de points [Termes IGN] télémètre laser terrestre Résumé : (Auteur) In recent years, the method of self-calibration widely used in photogrammetry has been found suitable for the estimation of systematic errors in terrestrial laser scanners. Since high correlations can be present between the estimated parameters, ways to reduce them have to be found. This paper presents a unified approach to self-calibration of terrestrial laser scanners, where the parameters in a least-squares adjustment are treated as observations by assigning appropriate weights to them. The higher these weights are the lower the parameter correlations are expected to be. Self-calibration of a pulsed laser scanner Leica Scan Station was performed with the unified approach. The scanner position and orientation were determined during the measurements with the help of a total station, and the point clouds were directly georeferenced. The significant systematic errors were zero error in the laser rangefinder and vertical circle index error. Most parameter correlations were comparatively low. In part, precise knowledge of the horizontal coordinates of the scanner centre helped greatly to achieve low correlation between these parameters and the zero error. The approach was shown to be advantageous to the use of adjustment with stochastic (weighted) inner constraints where the parameter correlations were higher. At the same time, the collimation error could not be estimated reliably due to its high correlation with the scanner azimuth because of a limited vertical distribution of the targets in the calibration field. While this problem can be solved for a scanner with a nearly spherical field-of-view, it will complicate the calibration of scanners with limited vertical field-of-view. Investigations into the influence of precision of the scanner position and levelling on the adjustment results lead to two important findings. First, it is not necessary to level the scanner during the measurements when using the unified approach since the parameter correlations are relatively low anyway. Second, the scanner position has to be known with a precision of about 1 mm in order to get a reliable estimate of the zero error. Numéro de notice : A2010-447 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.05.005 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.05.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30640 [article]

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Automatic detection of residential building using LIDAR data and multispectral imagery / M. Awrangjeb in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 5 (September - October 2010)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 457 - 467 Titre : Automatic detection of residential building using LIDAR data and multispectral imagery Type de document : Article/Communication Auteurs : M. Awrangjeb, Auteur ; M. Ravanbakhsh, Auteur ; Clive Simpson Fraser, Auteur Année de publication : 2010 Article en page(s) : pp 457 - 467 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] correction d'image [Termes IGN] détection du bâti [Termes IGN] données lidar [Termes IGN] image multibande [Termes IGN] masque [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] seuillage d'image Résumé : (Auteur) This paper presents an automatic building detection technique using LIDAR data and multispectral imagery. Two masks are obtained from the LIDAR data: a ‘primary building mask’ and a ‘secondary building mask’. The primary building mask indicates the void areas where the laser does not reach below a certain height threshold. The secondary building mask indicates the filled areas, from where the laser reflects, above the same threshold. Line segments are extracted from around the void areas in the primary building mask. Line segments around trees are removed using the normalized difference vegetation index derived from the orthorectified multispectral images. The initial building positions are obtained based on the remaining line segments. The complete buildings are detected from their initial positions using the two masks and multispectral images in the YIQ colour system. It is experimentally shown that the proposed technique can successfully detect urban residential buildings, when assessed in terms of 15 indices including completeness, correctness and quality. Numéro de notice : A2010-448 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.06.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.06.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30641 [article]

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A pre-screened and normalized multiple endmember spectral mixture analysis [MESMA] for mapping impervious surface area in Lake Kasumigaura Basin, Japan / F. Yang in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 5 (September - October 2010)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 65 n° 5 (September - October 2010) . - pp 479 - 490 Titre : A pre-screened and normalized multiple endmember spectral mixture analysis [MESMA] for mapping impervious surface area in Lake Kasumigaura Basin, Japan Type de document : Article/Communication Auteurs : F. Yang, Auteur ; B. Matsushita, Auteur ; T. Fukushima, Auteur Année de publication : 2010 Article en page(s) : pp 479 - 490 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse de mélange spectral d’extrémités multiples [Termes IGN] bassin hydrographique [Termes IGN] impact sur l'environnement [Termes IGN] Japon [Termes IGN] qualité des eaux [Termes IGN] surface imperméable [Termes IGN] urbanisation Résumé : (Auteur) The impervious surface area (ISA) has emerged not only as an indicator of the degree of urbanization, but also as a major indicator of environmental quality for drainage basin management. However, since almost all of the methods for estimating ISA have been developed for urban environments, it is questionable whether these methods can be successfully applied to drainage basins, such as those found in Japan, which usually have more complicated vegetation components (e.g. paddy field, plowed field and dense forest). This paper presents a pre-screened and normalized multiple endmember spectral mixture analysis (PNMESMA) method, which includes a new endmember selection strategy and an integration of the normalized spectral mixture analysis (NSMA) and multiple endmember spectral mixture analysis (MESMA), for estimating the ISA fraction in Lake Kasumigaura Basin, Japan. This new proposed method is superior to the previous methods in that the estimation error of the proposed method is much smaller than the previous SMA- or NSMA-based methods for drainage basin environments. The overall root mean square error was reduced to 5.2%, and no obvious underestimation or overestimation occurred for high or low ISA areas. Through the assessment of environmental quality in Lake Kasumigaura Basin using the ISA fraction, the results showed that the basin has been in the impacted category since 1987, and that in the two decades since, the environmental quality has continued to decline. If this decline continues, then Lake Kasumigaura Basin will fall into the degraded category by 2017. Numéro de notice : A2010-449 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.06.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.06.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30642 [article]

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