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Titre : Digitale Photogrammetrie in der dreidimensionalen Stromungsmesstechnik Titre original : [Photogrammétrie numérique dans la technique de mesure des courants en 3D] Type de document : Thèse/HDR Auteurs : Hans-Gerd Maas, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 1992 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 050 Importance : 140 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906513-07-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie terrestre
[Termes IGN] caméra numérique
[Termes IGN] chambre DTC
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] modèle mathématique
[Termes IGN] modélisation 3D
[Termes IGN] photogrammétrie numérique
[Termes IGN] traitement d'imageIndex. décimale : 33.70 Photogrammétrie terrestre Résumé : (auteur) Threedimensional particle tracking velocimetry (3D-PTV) is one of the most versatile instruments in flow measurement technique. It is based on discrete visualization of flows with small, reflecting, neutrally buoyant tracer particles and a stereoscopic recording of image sequences of the particles marking the flow. This thesis describes and analyzes an implementation of a fully automatic 3D-PTV based on solid state image sensors and methods of digital photogrammetry. After an overview on competing methods of flow measurement the hardware configuration of a 3D-PTV will be shown. An implementation at ETH Zurich, which mainly consists of off-the-shelf hardware components will be presented and some state-of-the-art components capable of improving the system will be discussed. Central points of the work is an exact modelling of the geometry of the experiment and the recording system, algorithmic aspects of image processing and establishment of stereoscopic correspondences in dense, truly threedimensional target fields and the calibration of the system. The processing of the image sequences with the aim of deriving particle trajectories begins with the determination of particle image coordinates by a modified thresholding operator in highpassfiltered images. Due to lack of features allowing a reliable distinction of particles the establishment of stereoscopic correspondences can only be based on the geometric criterium of the epipolar line. The large number of particles imaged (typically 1000 - 2000) will often lead to ambiguities, which cannot be solved by a system based on only two cameras. Therefore different arrangements and algorithms based on three or more cameras are being discussed, which are able to reduce the probability of the occurence of ambiguities drastically by exploiting the geometric constraint of a third camera. The geometric modelling has to consider the multimedia environment causing a twice broken beam from any particle in water to the sensor, which is accounted for by a multimedia module implemented into the collinearity condition; optical effects of the multimedia environment necessitate a calibration of the complete system in situ under the conditions of the experiment. The system described in the thesis is capable of determining velocity fields in flows with a spatial resolution of up to 1000 simultaneous velocity vectors at a temporal resolution of 25 vector fields per second and almost arbitrary sequence length completely automatically after an initialization by an operator. Numéro de notice : 47256 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-000627387 En ligne : http://dx.doi.org/10.3929/ethz-a-000627387 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=58636 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 47256-02 33.70 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible 47256-01 33.70 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible 47256-03 33.70 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible Geometric and radiometric analysis of a CCD-camera based photogrammetric close-range system / Horst A. Beyer (1992)
Titre : Geometric and radiometric analysis of a CCD-camera based photogrammetric close-range system Type de document : Thèse/HDR Auteurs : Horst A. Beyer, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 1992 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 051 Importance : 186 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906513-24-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] acquisition d'images
[Termes IGN] acquisition de données
[Termes IGN] calibrage
[Termes IGN] chambre DTC
[Termes IGN] contrôle qualité
[Termes IGN] éclairement lumineux
[Termes IGN] photogrammétrie métrologique
[Termes IGN] précision géométrique (imagerie)
[Termes IGN] qualité géométrique (image)
[Termes IGN] qualité radiométrique (image)Index. décimale : 35.10 Acquisition d'images Résumé : (Auteur) The advent of filmless imaging systems, especially of Charge-Coupled Devices (CCD), has created manifold opportunities and new applications which have led to significant changes in Photogrammetry. The exacting demands of Photogrammetry on the radiometric and geometric characteristics of the imaging sensor and all other elements involved in the acquisition of imagery with solid-state sensors, require a detailed analysis of the factors affecting the performance.
This analysis can build on extensive knowledge acquired over the last twenty years for the calibration of film based cameras. For example the modelling of systematic errors introduced by lenses is identical for both systems. Calibration and analysis techniques, such as the bundle adjustment with self-calibration, are important tools. Another source of a great deal of information are applications of solid-state sensors in astronomy. Exacting radiometric requirements have led to the development of specialized sensors, cameras, image acquisition systems, and calibration techniques. These techniques are currently only partially applicable to photogrammetric tasks though. They are tuned to be used with extremely specialized hardware (cameras, image acquisition systems, testing arrangements) which is typically not available for photogrammetric applications. One task of this dissertation was thus to investigate the effects of cameras, signal transmission techniques, and frame grabbers as they are widely available on the market as off-theshelf equipment. The individual components were investigated first, then the combined radiometric and geometric performance of the system was analyzed, and finally the performance of a system for three-dimensional measurements was verified. This in turn required the installation of an image acquisition system with advanced capabilities to perform various comparative investigations, to set up a three-dimensional testfield, and to write a large amount of software for analysis and calibration.
The geometric regularity and the excellent radiometric characteristics of solid-state sensors make them ideal measurement devices. A number of investigations have shown that the regularity of the sensor element spacing is in the order of 11100 of the spacing. The uniformity of response from sensor element to sensor element is 1 % and better for many off-the-shelf cameras. The geometric regularity of the sensor would thus allow to measure positions of targets imaged on such a sensor with a precision of I/100th of the spacing and better. This is actually achieved and surpassed with special sensors in star tracking applications. The mechanical design and the electronics of CCD-cameras are usually not designed for photogrammetric purposes. The mechanical design is often not sufficiently stable, i.e. the assembly of lens, housing and sensor is not rigid. The camera electronics are designed for visual purposes (e.g. surveillance), thus potentially introducing significant degradations due to a number of factors such a low-pass-filters, gamma correction, addition of video signals, to name but a few.
The largest drawback with respect to the radiometric and geometric performance, but an advantage with respect to economy, is the use of standard analog video signals for the transmission of the imagery acquired by solid-state sensors. These standards were developed in the 1950's for broadcasting and are not at all tuned for the requirements of precise measurements. The radiometric and geometric properties of these signals were analyzed, potential drawbacks discussed, as well as methods for determination and compensation and/or elimination of deficiencies investigated and performed.
Frame grabbers are another critical component of the image acquisition system. They must convert the analog transmitted imagery into matrices of numbers, the digital image.
The radiometric and geometric performance of a number of electronic components and of different synchronization techniques of the frame grabber were analyzed. These tests revealed a number of critical issues such as proper DC-restoration, degrading effects of low-pass-filters, deviations from linearity, low level patterns, and the performance of pixel-synchronous sampling as compared to PLL line- synchronization. This allows to separate influences of the frame grabber from those of the camera. The assessment of the effects of the two synchronization techniques, pixel-synchronous sampling and PLL line-synchronization, lead to the detection of a geometric deformation (which can be introduced when composite video signals are used in connection with PLL line-synchronization) and the confirmation of the degrading effects of line-jitter. It was furthermore shown that pixel- synchronous sampling provides a transmission without loss for photogrammetric purposes. The investigation of several radiometric characteristics of the complete system demonstrated some of the insufficiencies of typical off-the-shelf hardware. Potential trouble spots, such as degradations of the radiometric uniformity at the borders of the imagery, were detected. The difficulty of radiometric calibration of the system was addressed.
A test strategy for the assessment of the geometric stability of the system was developed. The effects of the synchronization on the radiometric performance was used to develop test methods to rapidly pinpoint imprecisions of the frame grabber synchronization. The analysis of the repeatability proved that pixel- synchronous frame grabbing provides identical geometric characteristics as digital transmission. The short time repeatability for both digital image transmission as well as pixel-synchronous sampling was shown to be in the order of 0.004 pixel. The analysis of PLL line--synchronization using pixel-synchronous frame grabbing as reference confirmed that line jitter reduces the internal precision in row direction by a factor of six. Disturbances of the PLL line-synchronization, introduced by composite video signals, were shown to lead to geometric deformations reaching 0.3 pixel. The study of warm-up-effects allowed to determine the minimal time required by the system (camera and frame grabber) to reach a steady state. When using pixel-synchronous sampling the major contributing factor to warm-up effects are thermally-induced deformations of the camera body, i.e. the assembly of lens and sensor. The geometric stability of the image acquisition system was verified with a test of over one week duration. It could be shown that for durations of several days a repeatability of well below 1/100th of a pixel can be achieved. Finally the effects of local variations of the illumination andlor of shadows on the position determination with Least-Squares Matching were analyzed. It was empirically demonstrated that gradients of a few per cent can lead to errors in the estimated position of several hundred's of a pixel.
The geometric precision and accuracy of the system was verified with a three-dimensional testfield. The part of the testfield used in the tests spans a volume of 2600 x 2000 x 1100 mm with 162 targets of 20 mm diameter. The position of the targets was determined with a precision of 0.02 to 0.03 mm by theodolite measurements. Two sets of 48 frames were acquired, one with pixel-synchronous sampling and the other with PLL line-synchronization. The relative accuracy attained with the pixel- synchronously grabbed imagery reaches 1 part in 50 000 in object space and is 1/85th of the pixel spacing in the image when using 30 control points were used. This is reduced to 1 part in 46 000 and 1/50th of the pixel spacing with a minimally constrained network. The accuracy attained with the imagery acquired with PLL line- synchronization is only slightly lower. It was thus shown that very high accuracies can be attained with PLL line-synchronization when appropriate modelling of the geometric deformation and a large number of images are used. A comparison of the object coordinates computed with the two data sets indicated a relative accuracy of 1 part in 70 000 and 60 000 for the X and Y axes respectively. The accuracy in image space of the comparison is 1/100th of the pixel spacing. Finally some factors which limit the accuracy and approaches for their elimination are discussed.Numéro de notice : 62708 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-000642182 En ligne : http://dx.doi.org/10.3929/ethz-a-000642182 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=61113 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 62708-01 35.10 Livre Centre de documentation En réserve M-103 Disponible 62708-02 35.10 Livre Centre de documentation En réserve M-103 Disponible Theoretische und experimentelle Genauigkeitsuntersuchungen für ein optisches Positionsmeßsystem zur hochgenauen Vermessung von bewegten Objekten / Peter Krzystek (1990)
Titre : Theoretische und experimentelle Genauigkeitsuntersuchungen für ein optisches Positionsmeßsystem zur hochgenauen Vermessung von bewegten Objekten Titre original : [Etude de la précision théorique et expérimentale d'un système optique de mesure de position pour une mesure de haute précision d'objets en mouvements] Type de document : Thèse/HDR Auteurs : Peter Krzystek, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1990 Collection : DGK - C Sous-collection : Dissertationen num. 363 Importance : 110 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9411-6 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] capteur optique
[Termes IGN] chambre DTC
[Termes IGN] erreur systématique
[Termes IGN] étalonnage d'instrument
[Termes IGN] interpolation bilinéaire
[Termes IGN] modèle mathématique
[Termes IGN] objet mobile
[Termes IGN] photodiode
[Termes IGN] précision géométrique (imagerie)Index. décimale : 30.03 Instruments de géodésie Numéro de notice : 59846 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=60645 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 59846-01 30.03 Livre Centre de documentation En réserve M-103 Disponible Einsatz von CCD-Kameras zur differentiellen Entzerrung photogrammetrischer Aufnahmen / F.J. Behr (1989)
Titre : Einsatz von CCD-Kameras zur differentiellen Entzerrung photogrammetrischer Aufnahmen Titre original : [Recours aux caméras CCD pour l'étalement différentiel des prises de vues photogrammétriques] Type de document : Thèse/HDR Auteurs : F.J. Behr, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1989 Collection : DGK - C Sous-collection : Dissertationen num. 356 Importance : 115 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9404-8 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Orthophotographie, orthoimage
[Termes IGN] arbre quadratique
[Termes IGN] chambre DTC
[Termes IGN] chambre métrique
[Termes IGN] interpolation bilinéaire
[Termes IGN] modèle numérique de terrain
[Termes IGN] orthophotographie
[Termes IGN] photogrammétrie architecturale
[Termes IGN] qualité géométrique (image)
[Termes IGN] qualité radiométrique (image)
[Termes IGN] rééchantillonnage
[Termes IGN] restitutionIndex. décimale : 33.50 Orthophotographie, orthoimage Numéro de notice : 59312 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=60551 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 59312-01 33.50 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible Problems in digital image acquisition with CCD cameras / J. Dahler (02/06/1987)Some aspects of the geometric calibration of CCD-cameras / Horst A. Beyer (02/06/1987)PermalinkContribution à la modélisation et à la résolution du problème de la vision passive tridimensionnelle par ordinateur / Philippe Marthon (1987)PermalinkReal-time image metrology with CCD cameras / Sabry F. El Hakim in Photogrammetric Engineering & Remote Sensing, PERS, vol 52 n° 11 (november 1986)PermalinkRapport sur le symposium de la commission 5 de l'ISPRS tenu à Ottawa du 16 au 19 juin 1986, 1. Rapport / Christian Meyer (1986)PermalinkRapport sur le symposium de la commission 5 de l'ISPRS tenu à Ottawa du 16 au 19 juin 1986, 2. [Papiers complémentaires] / Christian Meyer (1986)PermalinkCinquièmes Journées d'Optique Spatiale, 14 - 17 octobre 1975, Marseille, France / Centre national d'études spatiales (1975)Permalink