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Development of a new laser triangulation system based on an optical frame of reference / A. Abzal in Photogrammetric record, vol 26 n° 135 (September - November 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 135 (September - November 2011) . - pp 293 - 306 Titre : Development of a new laser triangulation system based on an optical frame of reference Type de document : Article/Communication Auteurs : A. Abzal, Auteur ; Masood Varshosaz, Auteur ; M. Saadatseresht, Auteur Année de publication : 2011 Article en page(s) : pp 293 - 306 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] balayage laser [Termes IGN] caméra numérique [Termes IGN] lasergrammétrie [Termes IGN] photographie terrestre [Termes IGN] précision géométrique (imagerie) [Termes IGN] triangulation locale Résumé : (Auteur) In this paper a new triangulation-based laser scanner is presented which has a simple, yet strong, flexible and low-cost structure. A digital camera and three laser line projectors are the main components of the system. One of the laser projectors is positioned vertically, while the other two are horizontal. The former scans the object, whereas the latter two establish an optical frame which is used, in part, to define the plane containing the vertical laser projector at each step of scanning. At each step, an image is taken which includes the object along with the projected laser lines. By intersecting the vertical and horizontal lines a couple of points are formed which, along with the calibration information of the system, enable the extraction of the object coordinates. Results of the tests carried out show that by using an optical frame of this nature, the process of scanning is greatly facilitated. That is, the scanner can easily be used to scan objects of different size and dimensions. Within the current configuration, the system enables measurements with an accuracy of 1/1600. Also, as the system has a rigorous basis, its accuracy can be increased if improved hardware is provided. Numéro de notice : A2011-385 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00646.x Date de publication en ligne : 14/09/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00646.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31164 [article]

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Terrestrial laser scan error in the presence of dense ground vegetation / S. Coveney in Photogrammetric record, vol 26 n° 135 (September - November 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 135 (September - November 2011) . - pp 307 - 324 Titre : Terrestrial laser scan error in the presence of dense ground vegetation Type de document : Article/Communication Auteurs : S. Coveney, Auteur ; A. Stewart Fotheringham, Auteur Année de publication : 2011 Article en page(s) : pp 307 - 324 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection d'erreur [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] erreur géométrique [Termes IGN] flore locale [Termes IGN] krigeage [Termes IGN] marais salé [Termes IGN] masque de végétation [Termes IGN] semis de points [Termes IGN] sol nu [Termes IGN] source d'erreur [Termes IGN] télémétrie laser terrestre [Termes IGN] validation des données Résumé : (Auteur) Terrestrial laser scanning (TLS) data-sets are seeing increasing use in geology, geomorphology, forestry and urban mapping. The ease of use, affordability and operational flexibility of TLS suggest that demand for it is likely to increase in large-scale mapping studies. However, its advantages may remain restricted to specific environments, because of difficulties in defining bare-ground level in the presence of ground-level vegetation. This paper seeks to clarify the component contributions to TLS elevation error deriving from vegetation occlusion, scan co-registration error, point cloud georeferencing error and target position definition in TLS point cloud data. A multi-scan single-returns TLS point cloud data-set of very high resolution (~250 points/m2) was acquired for an 11 hectare area of open, substantially flat and 100% vegetated coastal saltmarsh, providing data for the empirical quantification of TLS error. Errors deriving from the sources discussed are quantified, clarifying the potential proportional contribution of vegetation to other error sources. Initial data validation is applied to the TLS point cloud data after application of a local-lowest-point selection process, and repeat validation tests are applied to the resulting filtered point cloud after application of a kriging-based error adjustment and data fusion with GPS. The final results highlight the problem of representing bare ground effectively within TLS data captured in the presence of dense ground vegetation and clarify the component contributions of elevation error deriving from surveying and data processing. Numéro de notice : A2011-386 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00647.x Date de publication en ligne : 14/09/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00647.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31165 [article]

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Evaluation of the RPC model as a replacement for the spaceborne InSAR phase equation / G. Zhang in Photogrammetric record, vol 26 n° 135 (September - November 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 135 (September - November 2011) . - pp 325 - 338 Titre : Evaluation of the RPC model as a replacement for the spaceborne InSAR phase equation Type de document : Article/Communication Auteurs : G. Zhang, Auteur ; W. Fei, Auteur ; Z. Li, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 325 - 338 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] ajustement de paramètres [Termes IGN] image radar [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] modèle géométrique de prise de vue [Termes IGN] modèle par fonctions rationnelles [Termes IGN] phase Résumé : (Auteur) Synthetic aperture radar interferometry (InSAR) is an alternative to conventional stereoscopic SAR for extracting relative or absolute terrain elevation information. However, for different InSAR data-sets, the auxiliary parameters are different, which introduces differences in the SAR interferometry rigorous sensor model (RSM). The Rational Polynomial Coefficient (RPC) model is a generalised sensor model which makes full use of the auxiliary parameters of the satellite images, and the coefficients of the model are then solved by fitting the model to the RSM. Some work has been carried out previously to validate its substitutability for the SAR RSM, which is based on the Range–Doppler equations. Further, this paper aims to prove that the RPC model can also be used as a replacement for the InSAR phase equation and can be widely applied on different types of InSAR data-sets. Based on numerous tests, the modelling error of the RPC is analysed. This study found that the RPC model is suitable for InSAR data-sets and it can be used as a replacement for the phase equation. Numéro de notice : A2011-387 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00647.x Date de publication en ligne : 14/09/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00647.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31166 [article]

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Calibration of long focal length cameras in close range photogrammetry / Christos Stamatopoulos in Photogrammetric record, vol 26 n° 135 (September - November 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 135 (September - November 2011) . - pp 339 - 360 Titre : Calibration of long focal length cameras in close range photogrammetry Type de document : Article/Communication Auteurs : Christos Stamatopoulos, Auteur ; Clive Simpson Fraser, Auteur Année de publication : 2011 Article en page(s) : pp 339 - 360 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] auto-étalonnage [Termes IGN] caméra numérique [Termes IGN] colinéarité [Termes IGN] compensation par faisceaux [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] longueur focale [Termes IGN] photogrammétrie métrologique [Termes IGN] photogrammétrie terrestre Résumé : (Auteur) One of the practical impediments to the adoption of long focal length lenses in close range photogrammetry is the difficulty in network exterior orientation and self-calibration that can be encountered with the collinearity equation model when the camera field of view is smaller than around 10°. This paper reports on an investigation that examined two different avenues for improving the self-calibration of long focal length cameras. The first is a re-examination of the linearisation of the collinearity equations with additional calibration parameters, and especially determination of the coefficients in the design matrix corresponding to the interior orientation elements. The second is a new approach to the calculation of object space coordinates by employing an orthogonal projection model that can be formulated as a bundle adjustment with self-calibration. Accuracy aspects of both approaches are discussed and test cases employing both zoom and macro lenses are presented. Numéro de notice : A2011-388 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00648.x Date de publication en ligne : 14/09/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00648.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31167 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
106-2011031	RAB	Revue	Centre de documentation	En réserve L003	Disponible