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Ableitung von Bewegungsstrategien zur automatisierten, vollständigen Vermessung von Innerraumszenen auf autonom navigierender Plattform / Alexander Fietz (2012)
Titre : Ableitung von Bewegungsstrategien zur automatisierten, vollständigen Vermessung von Innerraumszenen auf autonom navigierender Plattform Titre original : [Détournement (ou dérivation) de stratégies de mouvement pour la mesure complète et automatisée de scènes spatiales intérieures sur la plate-forme de navigation autonome] Type de document : Thèse/HDR Auteurs : Alexander Fietz, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 685 Importance : 164 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5097-6 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] bloc photo
[Termes IGN] caméra numérique
[Termes IGN] compensation par faisceaux
[Termes IGN] données lidar
[Termes IGN] données localisées 2D
[Termes IGN] données localisées 3D
[Termes IGN] lasergrammétrie
[Termes IGN] photogrammétrie terrestre
[Termes IGN] plateforme
[Termes IGN] positionnement en intérieur
[Termes IGN] reconstruction 3D
[Termes IGN] robot
[Termes IGN] segment de droite
[Termes IGN] système de numérisation mobile
[Termes IGN] tachéomètre électronique
[Termes IGN] variance
Résumé : (Auteur) A fundamental task of an autonomous mobile robot is the ability of self-localization in its environment respectively in a map of it, available to the robot. Many applications require a localization that is as precise as possible. Thereby, a decisive factor is the accuracy but also the completeness of the map. The generated map can usually be seen as a necessary side-product. When considered from a surveying point of view, it is brought more into focus. The question is to what extent the spatial robot data can fulfill certain mapping requirements in terms of accuracy and completeness in a detailed enough manner to be useful to human users. Precise models of indoor environments are very useful in both public and private sectors. But since their procurement involves a great deal of effort, an automatical generation of indoor models is desirable.
The following thesis should make a contribution to this and tries to compose the techniques that are necessary to deliver interior models at the push of a button. Therefore, a mobile measuring system was designed, that is able to carry out complete and precise measurements of indoor environments. The system was build up in two stages. A mobile platform is equipped with a low-cost laser scanner in the basic stage. This build-up allows a precise exploration of indoor scenes in 2D. In an expansion stage the installation of a digital camera leads to an additional 3D reconstruction based on photogrammetric techniques.
The accuracy and quality of robotic mapping is primarily dependent on the sensors that are used. The software process to register the collected data in a common coordinate frame and to create a holistic map of the environment has an additional influence. In the field of scanning systems scan matching techniques or probabilistic filter approaches are used. In the case of 3D surveying, a photogrammetric reconstruction can be done by an estimation of feature points, which are extracted from a photo block, within a bundle adjustment process. Results can be optimized, if requirements and restrictions of these techniques are regarded in the data acquisition process, when the robot proceeds the exploration. A crucial aspect is the spatial sensor placement at a certain point of time in this process. In the field of robotics, sensor placement is controlled by positioning strategies, which normally are of overriding importance to all other processes. The majority of known positioning strategies have the primary aim to optimize the efficiency of the exploration, so that every measurement provides as much new spatial information as possible. Requirements of the data registration technique are neglected in contrast. This thesis presents positioning strategies for scanning 2D measurements as well as photogrammetric 3D measurements, which try to maximize the accuracy of the collected spatial data. A scanning 2D measuring system, which is able to explore previously unknown indoor environments and generate precise floor plans is presented in the first part of this thesis. The system iteratively visits measurement poses defined by a positioning strategy. 2D point clouds, collected at various positions, are transformed into a common coordinate system by the use of a scan matching technique. The latter takes advantage of the characteristic manifestation of office environments and extracts planar segments from the measured point clouds. Minimizing the sum of perpendicular distances to these segments, points of a new scan are transformed into the existing coordinate system with high accuracy. Precision and robustness are improved through iterative parameter refinement. The measuring system uses a positioning strategy, which is based on the global assumption that the environment can be described as a collection of line segments. Since segment ends indicate data gaps, exploration is pushed until their observation is complete. All accessible measuring positions, represented in an occupancy grid, are evaluated in terms of their explorative benefit by the strategy using a cost function. Exploration is stopped as soon as every section is observed with a desired resolution.
The second part of this work presents a positioning strategy to enable the recording of photo blocks that are suitable for a photogrammetric reconstruction. In the run-up of data acquisition possible pose configurations are determined using accuracy estimation. The assumption of plain environments allows a limitation to a 2D search problem regarding the choice of possible camera poses, whereby the combinatorial variety is reduced. Initial information of pose estimation provides a 2D map, generated by the system structure that was presented in the first part of this work. For predefined sections of the environment, pseudo-random pose constellations are derived iteratively from the map and compared with each other using a cost function. The cost function helps to predict the variances resulting from a bundle adjustment. Therefore the functional model of the bundle adjustment has to be projected on the R2 in a way that a geodetic network consisting of direction measurements remains. The size and the shape of the resulting error ellipses allow conclusions and a comparative consideration regarding the quality of camera pose candidates.
An essential part of the work is the empirical analysis of the systems, to evaluate their performance and the quality of the resulting spatial data. Various experiments in real indoor environments show that developed measurement methods can be applied in practice. In different sets of experiments initial conditions are varied to find out their influence on the measurement process or the result. In order to achieve reliable results, reference models of the experimental environments were created by the use of a total station.
In the case of scanner measurements, experiments show that the developed system is able to explore and measure also complex interiors. An examination of the point clouds show that the achieved accuracy comes up with surveying demands. On this issue, the presented technique outplays conventional measuring equipment. However, additional modeling shows that mainly fine structures of the environment are displayed wrongly or are even lost completely. Also the 3D measuring strategy is demonstrably superior to existing techniques. The purely passive technique leads to sparse point clouds, not dense enough to derive detailed environment models with the corresponding software.
Numéro de notice : 14621 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : sans En ligne : https://www.ifp.uni-stuttgart.de/dokumente/Dissertationen/diss-fietz-c-685.pdf Format de la ressource électronique : URL Permalink :
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Attributierte Grammatiken zur Rekonstruktion und Interpretation von Fassaden / J. Schmidtwilken (2012)
Titre : Attributierte Grammatiken zur Rekonstruktion und Interpretation von Fassaden Titre original : [Grammaires attribuées pour la reconstruction et l'interprétation des façades] Type de document : Thèse/HDR Auteurs : J. Schmidtwilken, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 686 Importance : 169 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5098-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] façade
[Termes IGN] objet géographique complexe
[Termes IGN] reconstruction 3D du bâti
[Termes IGN] semis de points
Résumé : (Auteur) The needs and benefits of highly detailed 3D city and building models is opposed to their expensive acquisition. Though the automatic derivation of simplified roof structures from aerial images or laser altimetry is mostly solved, only a few approaches for the automatic reconstruction of facade structures from terrestrial data were presented yet. Most of the existing work is on the interpretation of large, planar facades that are reduced to a regular arrangement of windows. Therefore, it lacks in both, the reconstruction of additional facade elements such as stairs or doors as well as methods for the interpretation of heterogeneous a,nd complex facades with protrusions, oriels and only a small number of windows.
This thesis deals with the interpretation of 3D point clouds that have been captured by terrestrial laser scanning of urban areas. The focus is on 3D point clouds of heterogeneous facades, that are characterized by their narrow width and by protrusions and oriels. The main contribution is the reconstruction and interpretation of facades by a parser that combines attribute grammars and robust estimators. Due to the generic attribute grammar the estimation of models with a previously unknown number of parameters is possible and the heterogeneity of the objects is thus considered.
The concept is distinguished by the heavily integration of prior knowledge. The geometric and the semantic model of facades are defined and transferred to the attributed grammar. Furthermore, the probability densities of the shape and position parameters of the considered facade parts are estimated and Incorporated in the attributed grammar. The corresponding a priori probabilities are essential for the presented robust estimator MOSAP and the parsing algorithm parseSd.
The relations between single parts of a facade are mapped to the attribute grammar. Therefore, the grammar represents the complex structures of facades and constitutes the foundation of the parsing algorithm. Beginning with the most common symbol parse3d iteratively applies production rules and, thus, generates hypothesis represented by derivation trees. Finally the most likely derivation tree is selected. Both, the selection of the symbol to be derived and the selection of the production rule to be applied base on the a priori probabilities and the densities that are estimated from the context information like the parameters of already reconstructed objects or subsets of the 3D point cloud. The interface between the grammar and the 3D point clouds is realized by the robust estimator MOSAP and guards. The latter determine the likelihood of a production rule and, therefore, provide a selection criterion.
The symbols of the grammar t.iat are geometrically defined by a small set of parameters axe reconstructed by a robust estimator. MOSAP (Model Based Sampling and Prediction) bases on the hypothesize-and-verify paradigm and is characterized by the model-based sampling strategy that takes advantage of the probability densities of the shape and position parameters of the objects to be reconstructed. Furthermore, MOSAP evaluates the hypothesis by the newly introduced goodness of prediction criterion.
Numéro de notice : 14499 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink :
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Effects on the geodetic-VLBI observables due to polarization leakage in the receivers / Alessandra Roy (2012)
Titre : Effects on the geodetic-VLBI observables due to polarization leakage in the receivers Type de document : Thèse/HDR Auteurs : Alessandra Roy, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 681 Importance : 160 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5093-8 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données ITGB
[Termes IGN] interférométrie à très grande base
[Termes IGN] polarisation
[Termes IGN] récepteur
Résumé : (Auteur) Geodetic VLBI delivers baseline length and Earth orientation parameter measurements, which offer the most viable and precise way to study Earth crustal and core dynamics and to support space navigation. The precision of these geodetic and astrometric measurements is degraded by instrumental errors of which polarization leakage is one of the larger. Its effect can be corrected in the data provided one knows the leakage characteristics of the stations. In this work I introduce the concept of polarization, why it needs to be considered in the geodetic analysis and present a VLBI experiment that measured the polarization leakage at 16 geodetic and VLBA stations over the frequency range 8212.99 MHz to 8932.99 MHz and 2225.99 MHz to 2365.99 MHz. I describe resulting polarization leakage measurements and the algorithm that was implemented to correct for their effect on the geodetic delay measurables. I applied the correction for polarization leakage to a routine geodetic VLBI experiment and check for the resulting improvement. Prom the measured leakage terms, one would expect polarization leakage to affect the group delay measurements by 0.5 ps to 7 ps, depending on the stations involved in the baseline. This proved to be below the statistical noise in a single VLBI experiment and so the improvement from the correction could not be detected. Polarization leakage was found, unexpectedly, not the dominant source of non-closing errors. Numéro de notice : 14618 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère En ligne : https://hdl.handle.net/20.500.11811/1408 Format de la ressource électronique : URL Permalink : Entwicklung eines Kalman-Filters zur Bestimmung kurzzeitiger Variationen des Erdschwerefeldes aus daten der Satellitenmission GRACE / E. Kurtenbach (2012)
Titre : Entwicklung eines Kalman-Filters zur Bestimmung kurzzeitiger Variationen des Erdschwerefeldes aus daten der Satellitenmission GRACE Titre original : Development of a Kalman filter to derive short-term variations of the Earth's gravity field from GRACE data Type de document : Thèse/HDR Auteurs : E. Kurtenbach, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 683 Importance : 120 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5095-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] corrélation automatique de points homologues
[Termes IGN] crénelage
[Termes IGN] données GRACE
[Termes IGN] filtre de Kalman
[Termes IGN] série temporelle
[Termes IGN] variation temporelle
Résumé : (Auteur) The gravitational field and its temporal variations represent an important observable for the monitoring of the Earth's system. The satellite mission GRACE (Gravity Recovery And Climate Experiment) is, for the first time, able to measure gravity field variations with homogeneous global coverage. Nevertheless, the predicted GRACE accuracy has not been reached yet, partly due to the insufficient representation of the temporal variations in terms of monthly mean fields. In this thesis, an approach is presented which allows the calculation of daily GRACE solutions with the goal of modeling short-term gravity field variations. This time series can on the one hand be used to improve the knowledge of the underlying geophysical processes. On the other hand the daily GRACE solutions can also be used to improve the monthly mean fields. Increasing the temporal resolution is accompanied by a loss of accuracy due to insufficient data coverage. Therefore, additional information in terms of temporal and spatial correlations of the expected gravity signal is introduced into the analysis process. The combination of the GRACE observations and the correlation patterns is then performed within a Kalman filter framework. In a simulation study, the performance of the approach at hand is investigated and, in a second step, applied to real GRACE LIB data. Comparisons to independent data sets, i.e. vertical displacements of GPS stations and ocean bottom pressure time series, reveal that the daily GRACE time series contains geophysically interpretable signal. Furthermore, the daily GRACE time series can be used to significantly reduce the effects of temporal aliasing in the processing of monthly mean gravity field solutions. Numéro de notice : 14619 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink :
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Geometrische und stochastische Modelle zur Verarbeitung von 3D-Kameradaten am Beispiel menschlicher Bewegungsanalysen / Patrick Westfeld (2012)
Titre : Geometrische und stochastische Modelle zur Verarbeitung von 3D-Kameradaten am Beispiel menschlicher Bewegungsanalysen Titre original : [Modèles aléatoires et géométriques pour le traitement de données de caméra 3D en utilisant l'exemple de l'analyse de mouvements humains] Type de document : Thèse/HDR Auteurs : Patrick Westfeld, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2012 Collection : DGK - C Sous-collection : Dissertationen num. 687 Importance : 283 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5099-0 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Applications photogrammétriques
[Termes IGN] chambre 3D
[Termes IGN] compensation par faisceaux
Résumé : (Auteur) The three-dimensional documentation of the form and location of any type of object using flexible photogrammetric methods and procedures plays a key role in a wide range of technical-industrial and scientific areas of application. Potential applications include measurement tasks in the automotive, machine building and ship building sectors, the compilation of complex 3D models in the fields of architecture, archaeology and monumental preservation and motion analyses in the fields of flow measurement technology, ballistics and medicine. In the case of close-range photogrammetry a variety of optical 3D measurement systems are used. Area sensor cameras arranged in single or multi-image configurations are used besides active triangulation procedures for surface measurement (e.g. using structured light or laser scanner systems).
The use of modulation techniques enables 3D cameras based on photomix detectors or similar principles to simultaneously produce both a grey value image and a range image. Functioning as single image sensors, they deliver spatially resolved surface data at video rate without the need for stereoscopic image matching. In the case of 3D motion analyses in particular, this leads to considerable reductions in complexity and computing time. 3D cameras combine the practicality of a digital camera with the 3D data acquisition potential of conventional surface measurement systems. Despite the relatively low spatial resolution currently achievable", as a mono-sensory real-time depth image acquisition system they represent an interesting alternative in the field of 3D motion analysis.
The use of 3D cameras as measuring instruments requires the modelling of deviations from the ideal projection model, and indeed the processing of the 3D camera data generated requires the targeted adaptation, development and further development of procedures in the fields of computer graphics and photogrammetry. This Ph. D. thesis therefore focuses on the development of methods of sensor calibration and 3D motion analysis in the context of investigations into inter-human motion behaviour. As a result of its intrinsic design and measurement principle, a 3D camera simultaneously provides amplitude and range data reconstructed from a measurement signal. The simultaneous integration of all data obtained using a 3D camera into an integrated approach is a logical consequence and represents the focus of current procedural development. On the one hand, the complementary characteristics of the observations made support each other due to the creation of a functional context for the measurement channels, with is to be expected to lead to increases in accuracy and reliability. On the other, the expansion of the stochastic model to include variance component estimation ensures that the heterogeneous information pool is fully exploited.
The integrated bundle adjustment developed facilitates the definition of precise 3D camera geometry and the estimation of range-measurement-specific correction parameters required for the modelling of the linear, cyclical and latency defectives of a distance measurement made using a 3D camera.
The integrated calibration routine jointly adjusts appropriate dimensions across both information channels, and also automatically estimates optimum observation weights. The method is based on the same flexible principle used in self-calibration, does not require spatial object data and therefore foregoes the time-consuming determination of reference distances with superior accuracy. The accuracy analyses carried out confirm the correctness of the proposed functional contexts, but nevertheless exhibit weaknesses in the form of non-parameterized range-measurement-specific errors. This notwithstanding, the future expansion of the mathematical model developed is guaranteed due to its adaptivity and modular implementation. The accuracy of a new 3D point coordinate can be set at 5 mm further to calibration. In the case of depth imaging technology - which is influenced by a range of usually simultaneously occurring noise sources - this level of accuracy is very promising, especially in terms of the development of evaluation algorithms based on corrected 3D camera data.
2.5D Least Squares Tracking (LST) is an integrated spatial and temporal matching method developed within the framework of this Ph. D. thesis for the purpose of evaluating 3D camera image sequences. The algorithm is based on the least squares image matching method already established in photogrammetry, and maps small surface segments of consecutive 3D camera data sets on top of one another. The mapping rule has been adapted to the data structure of a 3D camera on the basis of a 2D affine transformation. The closed parameterization combines both grey values and range values in an integrated model. In addition to the affine parameters used to include translation and rotation effects, the scale and inclination parameters model perspective-related deviations caused by distance changes in the line of sight. A pre-processing phase sees the calibration routine developed used to correct optical and distance-related measurement specific errors in input data and measured slope distances reduced to horizontal distances. 2.5D LSI i
an integrated approach, and therefore delivers fully three-dimensional displacement vectors. In addition, the accuracy and reliability data generated by error calculation can be used as decision criteria for integration into an application-specific processing chain. Process validation showed that the integration of complementary data leads to a more accurate, reliable solution to the correspondence problem, especially in the case of difficult contrast ratios within a channel. The accuracy of scale and inclination parameters directly linked to distance correction terms improved dramatically. In addition, the expansion of the geometric model led to significant benefits, and in particular for the matching of natural, not entirely planar surface segments.
The area-based object matching and object tracking method developed functions on the basis of 3D camera data gathered without object contact. It is therefore particularly suited to 3D motion analysis tasks in which the extra effort involved in multi-ocular experimental settings and the necessity of object signalling using target marks are to be avoided. The potential of the 3D camera matching approach has been demonstrated in two application scenarios in the field of research into human behaviour. As in the case of the use of 2.5 D LST to mark and then classify hand gestures accompanying verbal communication, the implementation of 2.5D LST in the proposed procedures for the determination of interpersonal distance and body orientation within the framework of pedagogical research into conflict regulation between pairs of child-age friends facilitates the automatic, effective, objective and high-resolution (from both a temporal and spatial perspective) acquisition and evaluation of data with relevance to behaviour.
This Ph. D. thesis proposes the use of a novel 3D range imaging camera to gather data on human behaviour, and presents both a calibration tool developed for data processing purposes and a method for the contact-free determination of dense 3D motion vector fields. It therefore makes a contribution to current efforts in the field of the automated videographic documentation of bodily motion within the framework of dyadic interaction, and shows that photogrammetric methods can also deliver valuable results within the framework of motion evaluation tasks in the as-yet relatively untapped field of behavioural research.
Numéro de notice : 14622 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : sans En ligne : https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa-88592 Format de la ressource électronique : URL Permalink : Robust determination of station positions and Earth orientation parameters by VLBI intra-technique combination / S. Böckmann (2012)PermalinkAnalyse des stochastischen Modells von GPS-Trägerphasenbeobachtungen / J. Howind (2005)PermalinkAutomatisierte Auswertung und Kalibrierung von scannenden Messsystemen mit tachymetrischem Messprinzip / A. Rietdorf (2005)PermalinkEin Beitrag zur Identifikation von dynamischen Strukturmodellen mit Methoden der adaptiven Kalman-Filterung / A. Eichhorn (2005)PermalinkGPS-Anwendungen in der Sportwissenschaft / T. Blumenbach (2005)PermalinkModelbasierte Segmentierung und Objekterkennung aus Distanzbildern / Jan Böhm (2005)PermalinkModellgestützte Kostenprognose für den Aufbau qualitätsgesicherter Geodatenbestände / M. Stark (2005)PermalinkMulti-Sensor-Photogrammetrie : Vision oder Wirklichkeit? / Norbert Haala (2005)PermalinkNicht-lineare Sensitivitätsanalyse gezeigt an Beispielen zu bewegten Objekten / Volker Schwieger (2005)PermalinkWavelettransformation hybrider Geländemodelle / G. Beyer (2005)Permalink