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Zur Automation berührungsloser 3D-Objekterfassung im Nahbereich / M. Hovenbitzer (2003)

Public Titre : Zur Automation berührungsloser 3D-Objekterfassung im Nahbereich Titre original : [L'automatisation de la saisie d'objet 3D à distance] Type de document : Thèse/HDR Auteurs : M. Hovenbitzer, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2003 Collection : DGK - C Sous-collection : Dissertationen num. 556 Importance : 82 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9595-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie terrestre [Termes descripteurs IGN] analyse comparative [Termes descripteurs IGN] détecteur à transfert de charge [Termes descripteurs IGN] données localisées 3D [Termes descripteurs IGN] étalonnage d'instrument [Termes descripteurs IGN] instrument de mesure [Termes descripteurs IGN] lasergrammétrie [Termes descripteurs IGN] photogrammétrie architecturale [Termes descripteurs IGN] photogrammétrie métrologique [Termes descripteurs IGN] primitive géométrique [Termes descripteurs IGN] primitive volumique [Termes descripteurs IGN] tachéomètre électronique [Termes descripteurs IGN] télémétrie laser terrestre Résumé : (Auteur) This thesis describes the realization and the calibration of two measurement systems, which are designed for measuring contactless three dimensional object points in close range. A well adapted way of data processing is presented, which shows the reduction from a large amount of object points to geometric parameters of object surfaces. First the possible applications for such systems are shown. The spectrum ranges from the interior scanning for facility management systems over documentations of archaeological excavations to virtual representations of buildings for purposes of the real estatetrade. Afterwards the existing up to date systems for measuring three dimensional coordinates in close range are described. The two developed measuring systems are described in detail. First the system Hybmess is introduced. The system is based on a standard motorized tacheometer. An additional CCDLinecamera is attached to the tacheometer below the telescope. The tacheometer is controlled by a computer to allow automatic positioning of the tacheometer and thus the camera. A projection unit is also mounted on the tacheometer. Structured light patterns are used to determine the object coordinates by intersection. The necessary Graycode patterns are projected by a laser beam deflected by a rotating prism. The interpretation of all projected patterns leads to a binary code for the last and most important pattern. This binary code contains the angle information which is necessary for calculating the intersection. The second measuring system MLMS determines the coordinates of surface points by reflectorless distance measurement. The base sensor of the measuring system is the unit LMS 200 of the SICK company. This sensor is able to measure fanshaped distances with an apex angle of 180'. The sensor measures with the time of flight principle. A motorized rotation stage turns the base sensor around the vertical axis, so that a three dimensional scanning of the object is possible. The processing of the measured data starts with the visualization of the scatterplot and results in a specification of the geometric parameters of the object. Two forms of visualization have been developed, which were well adapted to the measuring systems. The first form is the winding off visualization. Corresponding to the angle grid of the measurement system a picture is calculated, in which the local minima and maxima of the distances are marked with white dots. The second form of visualization is the perspective one. The gray value of the pixel depends on the distance between the central point and the object points. Because of the great amount of object points, the shapes of the object have to be extracted from the point cloud. For automatic respectively semiautomatic extraction of plains, spheres and cylinders algorithms have been developed. The intersection of these geometric shapes are corners or edges of the object. For scanning larger objects the combination of several instrument positions is necessary. The identical points can be the centers of measured spheres or the intersections of three measured plains. Mostly for the documentation of the object additional digital images are taken or the measurement system produces a digital image during the process of measuring. This additional information can be used for texturemapping the CADmodel of the object, or for measuring hidden objects or small details. The accuracy and precision of the new measuring systems is studied on some selected geometric objects. The scanning of interiors is an example for the presented way to combine several instrument positions. Numéro de notice : 13160 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54897

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Zur Bestimmung der GPS-Phasenmehrdeutigkeiten in großräumigen Netzen / K. Wienholz (2003)

Public Titre : Zur Bestimmung der GPS-Phasenmehrdeutigkeiten in großräumigen Netzen Titre original : [Vers la résolution des ambiguïtés de phase GPS dans les réseaux à grande échelle] Type de document : Thèse/HDR Auteurs : K. Wienholz, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2003 Collection : DGK - C Sous-collection : Dissertationen num. 566 Importance : 102 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5005-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] ambiguïté entière [Termes descripteurs IGN] ligne de base [Termes descripteurs IGN] logiciel de post-traitement GPS [Termes descripteurs IGN] mesurage de phase [Termes descripteurs IGN] modèle mathématique [Termes descripteurs IGN] phase GPS [Termes descripteurs IGN] propagation ionosphérique [Termes descripteurs IGN] résolution d'ambiguïté [Termes descripteurs IGN] traitement de données GNSS Résumé : (Auteur) The development and the results of the TUB method are presented in this paper. This special method serves in resolving GPS phase ambiguities in small-range and large-range networks. It is characterized by taking into account the correlates as quality criteria, thus enabling an assessment of the calculated ambiguities. First of all : by simulating an example to mediate the adjustment of conditions between unknown quantities it can be shown that every incorrect condition exerts a major constraint on the adjustment system. This constraint is reflected by the pertaining Lagrange factors (or correlates), the value of which increases rapidly in line with the magnitude of error in the equation of condition. This knowledge can be used in the TUB method to investigate various parameters. However, in this paper the emphasis is on the investigation of ambiguities. The TUB method is based on a special parameterization of the observation equations so that several unknown parameters are combined in one newly established time-dependent auxiliary parameter and in one timeindependent auxiliary parameter. By reduction of the unknown parameters a stable equation system is brought about which can be solved without resulting in differences and linear combinations. The direct analysis of original phase observations prevents the error-propagation of accidental errors and hence an artificial increase in phase noise. Therefore the confidence intervals, characterized by integer numbers, can be kept rather small. In finding these integer numbers the time-dependent auxiliary parameters must first be separated in different ways, depending on the lengths of the base lines, from the ionospheric refraction. Then the ambiguities in the form of double differences, related to a base satellite and a base station (or in the form of L1/L2 ambiguity pairs), can be solved in an iterative process. As a controlling device equations of condition are formed with the help of L1/L2 ambiguity pairs and inserted in the adjustment process. A subsequent analysis of the correlates gives information about the qualities of the ambiguities found. To begin with the potential of the TUB method is tested by means of a data set with base line lengths ranging from 13 to 48 km. By analyzing the correlates incorrect double difference ambiguities can be identified and among several integer numbers the correct one is filtered out. In two further nets with base line lengths from 26 to 106 km the influences of various more or less accurate orbits on the parameters of the observation equations are investigated. In the aforementioned examples a resolution of the ambiguities is possible at a success rate of 100 percent while an observation time of about two hours is sufficient. When terrain points are between 700 and 1000 km apart the model shows consider-able inaccuracies. The evaluation of data stemming from various IGS stations evidences that in about 20 percent of all ambiguities integer numbers cannot be found. In these cases the confidence intervals either do not provide any integer number or too many of them. In the latter case there are, instead of a single one, several LI/L2 ambiguity pairs that do not differ very much from one another. When these ambiguity pairs are inserted in the equation system the values of the correlates do not differ very much either. For the time being no satisfactory results can be achieved for base lines ranging between 1000 and 2000 km. The analysis of the correlates proves to be a useful tool in evaluating the quality of ambiguities. The correlates with the highest values occur when incorrect ambiguities exert major constraints on the equations of condition. In these cases errors can be detected, e.g., those arising from the use of broad-cast ephemerides. When several integer numbers are found in the confidence intervals the values of the correlates suggest values matching the normal equation system. Considerable interdependencies of the equations of condition are evident. Consequently there is an increase in the values that are linked to an incorrect condition via satellite and station. Therefore the correlations between the Lagrange factors should be investigated more closely. It is useful to determine the ambiguities of a data set by observation times of different lengths. By comparing the double difference ambiguities calculated from these solutions an additional examination of the results is made possible. Particularly when base lines of more than 1000 km are used it turns out that with data resulting from shorter observation times integer numbers can be calculated that would either not result at all or only inaccurately from longer measurements. The use of correlates as indicators for incorrect conditions is not only suitable for evaluating ambiguities in GPS analysis. Moreover, all parameters that can be formulated in appropriate conditions may be examined in any case of problems regarding the analysis of data. Numéro de notice : 13191 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54906

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Zur Höhensystemumstellung und Geoidberechnung in Bayern / C. Gerlach (2003)

Public Titre : Zur Höhensystemumstellung und Geoidberechnung in Bayern Titre original : [Sur le changement de système d'altitudes et l'estimation du géoïde en Bavière] Type de document : Thèse/HDR Auteurs : C. Gerlach, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2003 Collection : DGK - C Sous-collection : Dissertationen num. 571 Importance : 129 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5010-5 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] altitude normale [Termes descripteurs IGN] Bavière (Allemagne) [Termes descripteurs IGN] covariance [Termes descripteurs IGN] formule de Stokes [Termes descripteurs IGN] géoïde local [Termes descripteurs IGN] nivellement par GPS [Termes descripteurs IGN] précision décimétrique [Termes descripteurs IGN] problème des valeurs limites [Termes descripteurs IGN] réseau de premier ordre [Termes descripteurs IGN] système de référence altimétrique Résumé : (Auteur) Topographic heights are determined for various purposes and using different measurement techniques. This work gives a contribution to an accurate national height system for the federal state of Bavaria, Germany. One aspect is the determination of physical heights by means of geometric levelling combined with gravity measurements. The other aspect is to derive an accurate geoid in order to make use of the efficient method of levelling by GPS. Of course the definitions of the heights must be consistent with the used geoid. For both quantities (heights and geoid) there are different definitions and the differences between those cannot be neglected when in comes to the cm-level. For historic reasons, the former West-German national height system was computed in normal- orthometric heights and connected to the tide gauge Amsterdam. In the former German Democratic Republic normal heights were introduced, connected to a tide gauge in the Baltic sea. Thus, the reunification of Germany resulted in an inhomogeneous height system. The working group of the federal surveying authorities decided to set up a new consistent system, based on normal heights and connected to the level of Amsterdam. The first order network was computed in one step for the whole of Germany. It is the task of each federal state to compute the lower order networks for its own area. The first part of this work deals with height computations in the area of Bavaria. Transformation algorithms from the old spheroidal heights into normal heights are investigated under the precondition, that the use of the original measurement records should be avoided because not all of them are available in digital form. It is shown that in most parts of Bavaria a relatively simple procedure can be used, while in mountainous regions, like the Alps, gravity interpolation becomes the critical point. The accuracy requirements can still be met by using Bouguer anomalies (including topographic reductions) or by a proper distribution of data and interpolation points. The quality descriptions are based on a comprehensive error budget of all relevant error sources and make use of empirical covariance functions. As the new height system will be given in normal heights, the proper geoid is the quasi-geoid, based on the theory of Molodensky. The second part of this work deals with the computation of an accurate quasi-geoid in Bavaria. It is based on a combination of the global potential model EGM96 and terrestrial gravity anomalies within a 4° cap around Bavaria. A high resolution digital terrain model with a grid spacing of 50 m is used in Bavaria to compute topographic reductions. Molodensky's series is computed up to third order and different kinds of modifications of Stokes' function are tested. Comparison to GPS/Ievelling heights shows, that the best results are achieved using the original Stokes-kernel. Still there are long and medium wavelength errors of some decimeters in all solutions. This holds true for the European quasi-geoid EGG97, too. Error simulations indicate that those are due to errors in the global potential model. In order to allow the use of the derived quasi-geoid for the determination of physical heights, it is fitted to a set of GPS/Ievelling points. This way an accuracy of 2-3 cm is achieved, which is at the accuracy level of geodetic GPS measurements. Numéro de notice : 13201 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54911

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3D-Erfassung und Objektrekonstruktion mittels Streifenprojektion / J. Guhring (2002)

Public Titre : 3D-Erfassung und Objektrekonstruktion mittels Streifenprojektion Titre original : [Saisie 3D et reconstruction d'objet au moyen de la projection par bandes] Type de document : Thèse/HDR Auteurs : J. Guhring, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2002 Collection : DGK - C Sous-collection : Dissertationen num. 560 Importance : 166 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9599-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes descripteurs IGN] méthode robuste [Termes descripteurs IGN] modèle mathématique [Termes descripteurs IGN] reconstruction 3D Résumé : (Auteur) The digitization of physical objects using optical shape acquisition methods is gaining increasing importance. Nowadays, there are a lot of applications in many different fields like industrial inspection, reverse engineering, virtual reality and medicine. Due to the improvements in sensor architecture and data processing, the acquisition of objects of almost any complexity became possible. Active research during the last decades led to a variety of working shape acquisition systems worldwide. They differ in the measurement principle, efficiency and the degree of automatization. What almost all systems have in common is the missing or inadequate consideration of accuracy and reliability aspects. This thesis addresses the problem of surface acquisition and reconstruction using active optical triangulation. Compared to other systems, data quality is treated rigorously in all processing steps. In order to achieve this goal new methods or important extensions of existing methods have been developed. The necessary steps are : Data acquisition using structured light. Calibration and modeling of cameras and projectors is achieved by adapting well-established methods of digital close range photogrammetry to fringe projection systems. New pattern designs in combination with advanced processing methods allow for higher flexibility without introducing systematic measurement errors, as they are inherent in traditional methods. Results of the process are the geometric positions of the measured points, as well as, their covariance matrix and additional attributes like color or surface reflectivity. Transformation of datasets into a common coordinate frame. This so-called registration step is necessary since almost any measurement task requires multiple measurements from different viewpoints due to unavoidable occlusions. Algorithms for pairwise registration as well as algorithms for the simultaneous registration of multiple datasets and registration using surface reflectivity information have been investigated. All methods are modified versions of the well-known iterative closest point (ICP) algorithm and make use of covariance information provided by the data acquisition step. This information is used during the pose estimation process. A new stochastic model, which takes into consideration how point correspondences are computed, tremendously improves convergence compared to the classical ICP algorithm. The integration of registered datasets. This step modifies the topology of the measured points to yield a seamlessly integrated surface description. For measurement tasks in industrial inspection, the deviation between a manufactured part and its CAD description is necessary (actual/nominal comparison). The uncertainty of the reconstructed surface is used to decide whether a measured deviation is significant and if the measurements are precise enough to detect small defects. The realized system allows for the digitization of complex objects using millions of points. By the integration of accuracy and reliability aspects in all steps of the processing chain the robustness of the system has been considerably improved. Numéro de notice : 13162 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54899

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Am Puls von Raum und Zeit / J. Albetrz (2002)

Public Titre : Am Puls von Raum und Zeit : 50 Jahre Deutsche Geodätische Kommission Festschrift Type de document : Rapport Auteurs : J. Albetrz, Editeur scientifique ; Hans Peter Bähr, Editeur scientifique Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2002 Collection : DGK - E Sous-collection : Geschichte und Entwicklung der Geodäsie num. 026 Importance : 305 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9669-1 Note générale : Bibliographie Langues : Allemand (ger) Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] géodésie physique [Termes descripteurs IGN] photogrammétrie [Termes descripteurs IGN] système de référence géodésique Note de contenu : Grussworte - Bayerisches Staatsministerium für Wissenschaft, Forschung und Kunst - Bayerische Akadernie der Wissenschaften - Arbeitsgemeinschaft der Vermessungsvervaltungen der Länder der Bundesrepublik Deutschland (AdV) - Deutscher Verein für Vermessungswesen (DVW) - Deutsche Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation (DGPF) - Deutsche Gesellschaft für Kartographie (DGfK) - Union of Surveyors and Land Managers in Bulgaria - The Netherlands Geodetic Commission - Nordic Geodetic Commission (NKG) - Österreichische Geodätische Kommission (OGK) - Polish Academy of Sciences - The National Office for Cadastre, Geodesy and Cartography (NOCGC), Rumänien - Schweizerische Geodätische Kommission (SGK) - Geodätische Kommission der Ungarischen Akademie der Wissenschaften - Technische Universität Istanbul (ITÜ) Festvorträge - HANSPETER BAHR: Geodäsie Orientierung im Spannungsfeld der Gesellschaft - KAREL F. WAKKER: The European University in the 21st Century Fachvorträge - HERMANN DREWES: Die Entwicklung der geodätischen Referenzsyteme - CHRISTIAN HEIPKE: Photogrammetrie und Fernerkundung - Vom EIektronenmikroskop bis zur Planetenbeobachtung - H0LGER MAGEL: Bodenordnung und Landentwicklung- Beitrage zu einer nachhaltige (re)n und gerechte(re)n Welt - WOLFGANG BOSCH: Satellitenmissionen Chancen und Herausforderungen, für die Physikalische Geodäsie - HARALID SCHLEMMER: ingenieurgeodäsie für den einfachen Fall - LiQui MENG: Zur Entwicklung und Nutzung von Geodiensten Aus der Arbeit der Kommission Geschichte der Kommission - HELMUT HORNIK, GOTTLOB KIRSCHMER, KLAUS SCHNÄDELBACH, RUDOLF SIGL: 50 Jahre Deutsche Geodätische Kommission - DIETRICH MOLLER: Die Entwicklung der Satzung der Deutschen Geodätischen Kommission, Die erste Satzung vom 9. Juni 1952, Die aktuelle Satzung vom 13. Mai 1998 Arbeitskreise und Ausbildung - WOLFGANG TORGE: Schweregrundnetz. - KAR.L HEINZ ILK: Theoretische Geodäsie - HERMANN MÄLZER, JOHANNES VAN MIERLO, WOLFGANG AUGATH: Rezente Höhenänderungen /Krustenbewegungen - WALTER SEELE: Bodenordnung und Bodenwirtschraft (1981-1991) - RICHARD HOISL: Ländliche Neuordnung - RICHARD HOISL: Bodenordnung und Bodenwirtschraft (1991-1995) - ERICH WEISS: Bodenordnung und Bodenwirtschraft (1996-2002) - DIETRICH MORGENSTERN: Geoinformationssysteme - WILLFRIED SCHWARZ: Ingenieurvermessung - DIETRICH MÖLLER, BERTOLD WITTE: Hochschule und Ausbildungsfragen - Rahmenstudienordnung für den universitären Diplomstudiengang Geodäsie und Geoinformation in der Bundesrepublik Deutschland - GEODÄSIE 2000++ Ein Strategiepapier der Deutschen Geodätischen Kommission Deutsches Geodätisches Forschungsinstitut (DGFI) - KARLRUDOLF, KOCH: Die frühere Zentralleitung des Deutschen Geodätischen Forschungsinstituts - HERMANN DREWES: Das Deutsche Geodätische Forschungsinstilut ehemals Abteilung I Theoretische Geodäsie - HERMANN SEEGER, DIETMAR GRCNREICK, JOHANNES.IIIDE, BERNHARD WEICI1EL: Geschichte des Institut für Angewandte Geodäsie Abteilung II des DGFI Die Mitglieder der Deutschen Geodätischen Kommission - Mitglieder und Ständige Gäste der Deutschen Geodätischen Kommission (Stand Juli 2002) - Funktionen, Arbeitskreise, Ausschilsse tisw. in der Deutschen Geodätischen Kornmission (Stand Juli 2002) - Die Mitglieder der Deutschen Geodätischen Kommission (Biographische Daten) - Ständige Gäste der Deutschen Geodätischen Kommission Numéro de notice : 15104 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=40625

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An integrated approach to the Conceptual Data Modeling of an entire highway agency Geographic Information System (GIS) / Hande Demirel (2002)

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Der Einfluss von Sekundäreffekten auf die Rotation der Erde / R. Dill (2002)

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Extraktion von Straßennetzen aus optischen Satellitenbilddaten / C. Wiedemann (2002)

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Generalisierte Orthogonalzerlegungen in der Ausgleichungsrechnung / G. Dinter (2002)

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Inverse Probleme bei der Gravitationsfelsbestimmung mittels SST- und SGG-Satellitenmissionen Darstellungen / J. Kusche (2002)

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Konzeption, Entwicklung und Erprobung eines digitalen integrierten flugzeuggetragenen Fernerkundungssystems für Precision Farming (PFIFF) / Görres Grenzdorffer (2002)

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Regelbasierte Interpretation unstrukturierter Vektorkarten / M. Weindorf (2002)

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Schwerefeldfunktionale im Gebirge / J. Flury (2002)

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Statistische Untersuchung ganzzahliger und reellwertiger unbekannter Parameter im GPS-Modell / B. Gundlich (2002)

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Untersuchung von alternativen Messverfahren zur Brückenüberwachung am Beispiel der Klosterwegbrücke / Heiner Kuhlmann (2002)

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