Centre de documentation
scientifique

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 IGN] analyse comparative [Termes IGN] détecteur à transfert de charge [Termes IGN] données localisées 3D [Termes IGN] étalonnage d'instrument [Termes IGN] instrument de mesure [Termes IGN] lasergrammétrie [Termes IGN] photogrammétrie architecturale [Termes IGN] photogrammétrie métrologique [Termes IGN] primitive géométrique [Termes IGN] primitive volumique [Termes IGN] semis de points [Termes IGN] tachéomètre électronique [Termes IGN] télémétrie laser terrestre Index. décimale : 33.70 Photogrammétrie 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

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
13160-01	33.70	Livre	Centre de documentation	Photogrammétrie - Lasergrammétrie	Disponible