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Photo orientation under unstable conditions: a robust trial and error approach using range ratios / Arie Croitoru in Photogrammetric record, vol 17 n° 97 (April - September 2001)
[article]
Titre : Photo orientation under unstable conditions: a robust trial and error approach using range ratios Type de document : Article/Communication Auteurs : Arie Croitoru, Auteur ; U. Ethrog, Auteur Année de publication : 2001 Article en page(s) : pp 63 - 88 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] coplanarité
[Termes IGN] itération
[Termes IGN] méthode robuste
[Termes IGN] orientation relative
[Termes IGN] photogrammétrie métrologique
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] relèvementRésumé : (Auteur) L'orientation relative est l'une des étapes fondamentales dans la formation des modèles en photogrammétrie. Si cette orientation s'opère sans problème dans la plupart (les cas rencontrés en photogrammétrie aérienne), cela peut ne pas être le cas dans la photogrammétrie à courte distance, où la nature des photographies et des caméras utilisées soulève souvent des problèmes particuliers. On aborde dans cet article le problème de la formation de l'orientation relative de photographies non-métriques dans des conditions d'instabilité caractérisées par l'absence de points d'appui au sol et la mauvaise qualité géométrique du schéma de prise de vues. On traite le problème de l'orientation relative à partir de plusieurs points de vue, notamment avec une méthode qui se contente d'informations réduites sur les paramètres d'orientations relative et externe. Il s'agit d'une méthode itérative dans laquelle on constitue un jeu de trois points d'appui virtuels (VCPs) en utilisant les coordonnées-clichés et les rapports de distances de ces points au centre perspectif. On contrôle la validité de ces points VCP à chaque itération par une estimation basée sur la condition de coplanarité à l'aide de points de vérification, au nombre de deux ou plus. Pendant les itérations, on établit une base de données locale qui permet d'établir un réseau de points VCP satisfaisant à la condition de coplanarité pour les points de vérification et l'orientation relative externe s'obtient par un relèvement dans l'espace. On a essayé cette méthode à la fois dans un cas réel et avec des photographies simulées et on lui a trouvé des avantages sur les techniques plus communément utilisées. Numéro de notice : A2001-061 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/0031-868X.00168 En ligne : https://doi.org/10.1111/0031-868X.00168 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26400
in Photogrammetric record > vol 17 n° 97 (April - September 2001) . - pp 63 - 88[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 106-01011 RAB Revue Centre de documentation En réserve L003 Disponible 106-01012 RAB Revue Centre de documentation En réserve L003 Disponible Genauigkeitsuntersuchungen zur GPS/INS-Integration in der Aerophotogrammetrie / Michael Cramer (2001)
Titre : Genauigkeitsuntersuchungen zur GPS/INS-Integration in der Aerophotogrammetrie Titre original : [Recherches de l'exactitude pour l'intégration GPS/INS en photogrammétrie aérienne] Type de document : Thèse/HDR Auteurs : Michael Cramer, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2001 Collection : DGK - C Sous-collection : Dissertationen num. 537 Importance : 120 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9576-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] aérotriangulation
[Termes IGN] centrale inertielle
[Termes IGN] élément d'orientation externe
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] filtre de Kalman
[Termes IGN] géoréférencement direct
[Termes IGN] GPS-INS
[Termes IGN] image aérienne
[Termes IGN] orientation du capteur
[Termes IGN] orientation externe
[Termes IGN] point de vérification
[Termes IGN] précision de localisation
[Termes IGN] prise de vue aérienne
[Termes IGN] recouvrement d'imagesIndex. décimale : 33.30 Photogrammétrie numérique Résumé : (Auteur) Within this thesis different approaches for the direct measurement of exterior orientation elements of airborne sensors using integrated GPS/INS modules are investigated. The main focus is laid on the analysis of the accuracy potential of a commercially available integrated GPS/INS module using the "standard" approach for direct georeferencing : the integration of continuously recorded GPS and INS data in a Kalman filter approach. This method, originally developed for navigation purposes, is compared to a more straightforward strip-wise approach, which allows, in combination with an imaging sensor, the direct orientation determination even for short time intervals and data segments during photogrammetric strips. Beforehand, the basic principles of GPS/INS integration and the different system-characteristics of GPS and INS are summarized.
The two different approaches for GPS/INS integration mentioned before are investigated on their accuracy performance. For the accuracy analysis the GPS/INS module was combined with a standard analogue aerial camera and flown over a well controlled photogrammetric test site. Utilizing the standard approach of indirect image orientation applying the method of aerial triangulation independent exterior orientations for the discrete camera air stations are obtained and can be used for the estimation of the accuracy potential from GPS/INS. For tile tested commercial GPS/INS module the obtained quality of directly measured orientation elements in an operational airborne environment was about ~10cm for the positioning and ~15” for the attitude. Using the GPS/INS exterior orientations for direct georeferencing without ground control an accuracy of about 8-11µm and 15-23µm in image space is obtained for horizontal and vertical components, respectively. Transferring the accuracy on medium scale photo flight from an altitude of about 2000m above ground, object points are determined with an accuracy of 10-20cm for the horizontal and 20-30cm for the vertical coordinates. This accuracy even holds for the photogrammetrically problematic case of single flight lines. The use of stronger image overlap is of positive influence on the quality of object point determination. Using the second approach of strip-wise GPS/INS evaluation in a combined AT approach similar accuracy is obtained from the same data set. Therefore, this approach offers an alternative orientation method for imaging sensors in case of non-continuously recorded INS data.
The accuracy potential of GPS/INS integration is dependent on the quality of the used sensors and the quality of the GPS update information. The influence of the remaining errors in GPS/INS positions and attitudes on the object point determination is related on the actual flying height. For large scale imagery recorded from lower altitudes positioning errors are of major influence, whereas for higher altitudes remaining attitude errors are the main part of the error budget. Additionally, the overall system quality including the GPS/INS orientation components and the imaging sensor is strongly dependent on the correct overall system calibration. Within this context system calibration is not only restricted on the correct determination of the time and spatial eccentricities between the different sensor components but the calibration of the imaging sensor itself is of major importance. Since there is no possibility of subsequent self-calibration in direct georeferencing, every difference between the assumed mathematical model and the true physical environment during data recording will cause errors in object space. Within the analyzed data set scale dependent errors in the vertical coordinate are present. which could be modelled by slightly modifying the camera focal length used for data evaluation.
The obtained empirical accuracy is of major interest for the subsequent operational use of direct georeferencing in a standard photogrammetric environment. Due to this, the GPS/INS orientation accuracy is calculated using different baseline lengths between aircraft and reference station and varying image overlap and block geometry. Additionally, the influence of interpolation errors on varying data rates used for GPS/INS trajectory computations is estimated. Against the background of direct georeferencing using GPS/INS in photogrammetric practice - without ground control in the ideal case - the overall system requirements are discussed. In the final part of this thesis the possible future use of direct GPS/INS orientation measurements in photogrammetric practice is pointed out.Numéro de notice : 27826 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : sans En ligne : https://www.ifp.uni-stuttgart.de/dokumente/Dissertationen/Cramer_Diss.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=56450 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 27826-02 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible 27826-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible Orientation of optical airborne and spaceborne images for small and medium scale mapping purposes / Eija Honkavaara (1999)
Titre : Orientation of optical airborne and spaceborne images for small and medium scale mapping purposes Type de document : Rapport Auteurs : Eija Honkavaara, Auteur ; Mirjam Bilker, Auteur ; X. Yu, Auteur ; Juha Jaakkola, Auteur ; Harri Kaartinen, Auteur ; J. Ylonen, Auteur Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 1999 Collection : Reports of the Finnish Geodetic Institute num. 99-5 Importance : 57 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] aérotriangulation
[Termes IGN] image aérienne
[Termes IGN] image JERS
[Termes IGN] image optique
[Termes IGN] image spatiale
[Termes IGN] orientation d'image
[Termes IGN] orientation du capteur
[Termes IGN] photographie à moyenne échelle
[Termes IGN] photographie à petite échelle
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] points homologuesIndex. décimale : 33.30 Photogrammétrie numérique Résumé : (Auteur) Recent technical progress has resulted in significant improvement of the orientation process. The most revolutionary developments include automation of tie point measurement and direct determination of orientation parameters with GPS and INS techniques. Options to be taken into account when selecting materials for mapping and methods for orientation include image type (scale; standard frame, digital camera; spaceborne, airborne), block geometry (single image orientation, aerial triangulation (AT)), ground control (targeted, untargeted, GIS data, etc.), image observations (automatic, interactive) and utilisation of directly measured orientation parameters. The task is to optimise costs, accuracy and reliability.
These questions have been investigated at the Finnish Geodetic Institute (FGI) for medium and small scale mapping applications with spatial resolution and accuracy requirements for 15 m. Both theoretical and empirical considerations have been made with respect to several variables: observations of orientation parameters (GPS, no GPS, GPS processing), block structure (cross strips, no cross strips; single image, block), ground control points (GCPs, targeted, untargeted and GIS data: nationwide digital orthophotos, base maps and elevation models), image observations of tie points and GCPs (interactive, automatic) and image material (1:31 000 and 1:60 000 standard airborne images with approximately 1 m and 5 m pixel sizes; JERS/VNIR satellite images). All the airborne cases were analysed using the same strategies and checkpoints. JERSIVNIR images were analysed in parallel with the airborne images, but no comprehensive comparisons between the materials could be made because of large resolution differences.
The results of GPS measurements of perspective centres showed offsets and linear drifts varying from strip to strip, but compensation in AT with minimum ground control was possible. Targeted GCPs yielded high accuracy and reliability. Untargeted GCPs and GIS data as ground control, especially digital orthophotos and DEM25, also yielded good accuracy, although care is needed to avoid problems with gross errors. With GIS data, systematic errors can also be expected. The empirical and simulation results obtained make it possible to select GCP materials for obtaining various accuracy levels in the cases of spatial resection and AT with or without GPS support. It was concluded that in block adjustment, a planimetric accuracy of 10 gm in the image and a height accuracy of 0.1%oH can be obtained by using a reasonable number of GCPs (e.g. in 4 base distances) with accuracy better than 20 µm in image. Several examples of suitable GCP materials and configurations for obtaining accuracy better than 1 m were given. High accuracy was obtained with automatic tie point measurement, but investigations are still needed concerning optimal adjustment methods and number of points. The results, however, were in any case sufficient for applications with medium quality requirements. Experiences of orientation of JERS/VNIR images with rigorous methods were good; accuracy of 0.4 pixels was obtained with only 4 GCPs. In all the cases, the results of empirical and theoretical investigations correlated as long as the assumptions were valid; therefore reliable knowledge of the quality of the materials used as the basis for orientation is an important presupposition.Numéro de notice : 67564 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=44680 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 67564-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible GIS-basierte Quantifizierung der Denudation im Zentralen Kenia Rift / S. Rössner (1997)
Titre : GIS-basierte Quantifizierung der Denudation im Zentralen Kenia Rift Titre original : [Quantification basée sur le SIG de la dénudation du rift central au Kenya] Type de document : Thèse/HDR Auteurs : S. Rössner, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1997 Collection : DGK - C Sous-collection : Dissertationen num. 475 Importance : 111 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9515-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] données géologiques
[Termes IGN] érosion
[Termes IGN] géologie locale
[Termes IGN] Kenya
[Termes IGN] modèle numérique de terrain
[Termes IGN] point de vérification
[Termes IGN] positionnement par GPS
[Termes IGN] rift
[Termes IGN] système d'information géographique
[Termes IGN] variabilitéRésumé : (Auteur) In this work a GIS-based approach for quantification of average surface lowering (denudation) was developed. The goal in using a GIS (Geographic Information System) was to explore the methodological opportunities of a GIS in order to obtain spatially high-resolution denudation rates which form the basis for investigations of the regional variability of denudation and its relationship to other landscape-forming factors.
Such a spatially differentiated view of denudation requires a landscape frame of reference which allows direct quantification of the amount of eroded material in the source area of denudation. Within the Bahati-Kinangop Plateau (Central Kenya Rift) this condition is fulfilled for a 700 sq. km. area, where the highest topography is formed by relict elements of a dated erosional surface. These relict parts of the present relief are used to reconstruct the pre-erosional surface at the time when the plateau came into existence (about 3 Ma ago). The elevation difference between the pre-erosional and the present relief represents the amount of denudation since plateau formation. Thus, present topography is a direct measure of the long-term avarage intensity of denudation during the last 3 Ma in this area.
Calculation of denudation rates using the elevation difference method consisted of several steps. It included the derivation of modelling assumptions which were needed for reconstruction of the initial plateau surface based on the geological-tectonic evolution of the area. Additionally, the analogous geo-scientific and topographic data had to be integrated into a digital database in order to perform a quantification of denudation rates within a GIS.
Due to the close morphological relationship between inital and present surfaces, the generation of a Digital Elevation Model (DEM) of the present surface formed the starting point of the GIS-based data analysis. This DEM was obtained from contours of the 1:50.000 topographic maps by creating a triangulated irregular network (TIN) forming the basis for a regular raster interpolation. In order to achieve an average height accuracy in the range of half of an equidistance, a control point based approach was developed. It assess the height accuracy of the DEM in relation to map control points as well as to the real surface as determined by relative GPS measurements in the field.
The reconstruction of the initial plateau surface is based on a combined analysis of topographic and geological information within the GIS which resulted in 96 relict surface elements representing the input information for digital modelling of the pre-erosional relief. Plausibility checks showed that the generated initial surface is in overall accordance to the modelling assumptions. The denudation rates which were derived from the elevation differences between the two DEMs vary between 1 and 20 m/Ma in about 75 % of the study area. The most deeply eroded areas are characterized by rates between 45 and 100 m/Ma and are limited to 5 % of the area. The relict parts of the relief with denudation rates between 0 and 1 m/Ma occupy about 5 % of the area. These results compare well with rates typical for tectonically stable highland areas of Africa.
This GIS-based approach allows assessment of denuation rates in a well understood and reliable way. The results are characterized by a high spatial resolution which has not been obtained so far by other methods used for quantification of denudation. These high resolution rates offer the opportunity of a differentiated regional analysis. As long-term avarage rates they reflect the natural intensity of denudation. Such information are of special value in this area of present intense farming, because they can be used for estimating the influence of human landuse on the intensity of denudation.
(Auteur)In this work a GIS-based approach for quantification of average surface lowering (denudation) was developed. The goal in using a GIS (Geographic Information System) was to explore the methodological opportunities of a GIS in order to obtain spatially high-resolution denudation rates which form the basis for investigations of the regional variability of denudation and its relationship to other landscape-forming factors.
Such a spatially differentiated view of denudation requires a landscape frame of reference which allows direct quantification of the amount of eroded material in the source area of denudation. Within the Bahati-Kinangop Plateau (Central Kenya Rift) this condition is fulfilled for a 700 sq. km. area, where the highest topography is formed by relict elements of a dated erosional surface. These relict parts of the present relief are used to reconstruct the pre-erosional surface at the time when the plateau came into existence (about 3 Ma ago). The elevation difference between the pre-erosional and the present relief represents the amount of denudation since plateau formation. Thus, present topography is a direct measure of the long-term avarage intensity of denudation during the last 3 Ma in this area.
Calculation of denudation rates using the elevation difference method consisted of several steps. It included the derivation of modelling assumptions which were needed for reconstruction of the initial plateau surface based on the geological-tectonic evolution of the area. Additionally, the analogous geo-scientific and topographic data had to be integrated into a digital database in order to perform a quantification of denudation rates within a GIS.
Due to the close morphological relationship between inital and present surfaces, the generation of a Digital Elevation Model (DEM) of the present surface formed the starting point of the GIS-based data analysis. This DEM was obtained from contours of the 1:50.000 topographic maps by creating a triangulated irregular network (TIN) forming the basis for a regular raster interpolation. In order to achieve an average height accuracy in the range of half of an equidistance, a control point based approach was developed. It assess the height accuracy of the DEM in relation to map control points as well as to the real surface as determined by relative GPS measurements in the field.
The reconstruction of the initial plateau surface is based on a combined analysis of topographic and geological information within the GIS which resulted in 96 relict surface elements representing the input information for digital modelling of the pre-erosional relief. Plausibility checks showed that the generated initial surface is in overall accordance to the modelling assumptions. The denudation rates which were derived from the elevation differences between the two DEMs vary between 1 and 20 m/Ma in about 75 % of the study area. The most deeply eroded areas are characterized by rates between 45 and 100 m/Ma and are limited to 5 % of the area. The relict parts of the relief with denudation rates between 0 and 1 m/Ma occupy about 5 % of the area. These results compare well with rates typical for tectonically stable highland areas of Africa.
This GIS-based approach allows assessment of denuation rates in a well understood and reliable way. The results are characterized by a high spatial resolution which has not been obtained so far by other methods used for quantification of denudation. These high resolution rates offer the opportunity of a differentiated regional analysis. As long-term avarage rates they reflect the natural intensity of denudation. Such information are of special value in this area of present intense farming, because they can be used for estimating the influence of human landuse on the intensity of denudation.Numéro de notice : 28015 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63362 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28015-01 37.40 Livre Centre de documentation Géomatique Disponible 28015-02 37.40 Livre Centre de documentation Géomatique Disponible Practical experience with GPS supported aerial triangulation : paper read at the one-day symposium of the society, entitled GPS and photogrammetry on 1st November 1993 / F. Ackermann in Photogrammetric record, vol 14 n° 84 (October 1994 - March 1995)
[article]
Titre : Practical experience with GPS supported aerial triangulation : paper read at the one-day symposium of the society, entitled GPS and photogrammetry on 1st November 1993 Type de document : Article/Communication Auteurs : F. Ackermann, Auteur Année de publication : 1994 Article en page(s) : pp 861 - 874 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Photogrammétrie analytique
[Termes IGN] aérotriangulation
[Termes IGN] compensation par bloc
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] positionnement par GPS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] véhicule aérienRésumé : (Auteur) The operational situation of precise airborne GPS positioning of camera air stations and its use in combined block adjustment for aerial triangulation is reviewed. The acceptance of systematic GPS errors, which occur especially with biased phase ambiguity solutions after loss of lock of signals in-flight, has motivated the method of additional linear GPS drift parameters which are to be solved in the combined block adjutment. It also implies that no absolute GPS coordinates are required and that the datum transformation is provided via a few ground control points. A great number of practical examples demonstrates that the method has been successfully applied within a wide range of photoscales and of block sizes. It has proved to be fully operational under various pratical conditions. The high accuracy performance of GPS blocks and the economic benefit have been confirmed. It is particularly noticeable that the stationary receiver can be at a great distance, up to 500 km or more from the mission area. The conclusion is drawn that GPS supported aerial triangulation is ready to become standard. The potential improvement from dual frequency receivers and fast ambiguity solutions only enhances that conclusion. Numéro de notice : A1994-026 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.1994.tb00287.x En ligne : https://doi.org/10.1111/j.1477-9730.1994.tb00287.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=25730
in Photogrammetric record > vol 14 n° 84 (October 1994 - March 1995) . - pp 861 - 874[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 106-94022 RAB Revue Centre de documentation En réserve L003 Disponible 106-94021 RAB Revue Centre de documentation En réserve L003 Disponible Bildorientierung und Objektrekonstruktion mit Punkten, Linien und Flächen / Günter Strunz (1993)PermalinkMap compilation and revision in developing areas / J. Rollin (1988)PermalinkMéthode dynamique de recherche de points de contrôle pour le recalage de deux images / Agnès Anglade (1987)PermalinkTheorie und Untersuchung der Trennbarkeit von groben Paßpunktfehlern und systematischen Bildfehlern bei der photogrammetrischen Punktbestimmung / D. Li (1987)PermalinkPaßpunktbestimmung und geometrische Genauigkeit bei der relativen Entzerrung von Abtastdaten / W. Wiesel (1981)Permalink