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Theses

Dreidimensionale Skizzen in Erweiterter Realität

Abstract : Augmented Reality (AR) aims to fuse artificial and natural sensations to a consistent total perception. In doing so, the user should have the impression, that the virtual objects are part of the augmented physical world. In this augmented world the user can interact meaningfully with the perceived virtual objects. This work uses the AR-technology, in order to merge natural and artificial sensory information of the visual perception. AR can serve as medium, with which information is made available and can be exchanged at the right time, at the correct place and in the correct interrelation with the physical world. Though, this information can originate from existing data collections, whose objects have a spatial relation to the physical world, it happens frequently, that new information objects and maybe their geometry should be registered. AR is to help to communicate spatial data of defined meaning with oneself or others. The characteristic of communication using AR is that the information is taken at the same time both from physical world and from virtual world. The thesis proposes to use AR in the context of disaster management. AR can there be used to simplify the information exchange to coordinate the rescue measures after an disastrous event. To use AR efficiently for disaster management three-dimensional information is needed. It is therefore a new method developed to sketch virtual geometries directly into the physical world. These sketches can be used to create three-dimensional data to describe disaster relevant information on site. The generated information needs to be integrated in an overall information management strategy. It is shown how the geometric information is linked to a general data model that can be used for information management for rescue measures. The availability of information can be improved by AR since the information can be theoretically delivered exactly to the place where it is needed. However, this task can only be performed, if position and orientation of the user can be tracked over wide areas. To provide continuously position and orientation for regions of large extent adequate sensors are needed. In this study a combination of GPS and INS is used. The integration of these sensors requires special calibration techniques. To determine all calibration parameters, a new calibration strategy was developed. To describe the strategy several transformations on the structure of the mathematical model had to be applied. To describe the transformation of the structures, an adopted notation is given. Having calibrated the AR-System, the problem of creating sketches that are embedded into the physical world is approached. Sketches made on paper fulfil in general several functions. In some cases, it is additionally desired, that the sketched information can be viewed three dimensionally from different perspectives. Such sketches are called in this thesis ” three-dimensional sketches“ to point out, that these sketches do not only represent a three-dimensional object, but they are also represented them-selves in three dimensions.The third dimension is derived from sketches that are drawn from different perspectives. As long as the user is drawing, while no three-dimensional representation is available, a method is needed, that can approximately overlay the drawing with the correct location in the image plane, even if the image plane is moving continuously. In contrast to other methods described in literature the method given here enables one to create polygonal sketch elements from distance, without touching the physical location of the polygon. The approach takes into account that the users may draw sketches with different level of details and that they may make mistakes when drawing in perspective. The reconstructed curve has the same topology as the measured one. The described method is demonstrated by examples and the sensibility of the algorithm and the accuracy of the results are discussed. Finally, further developments, possible extensions and technical improvements are proposed.
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  • HAL Id : tel-00275264, version 1

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Johannes Leebmann. Dreidimensionale Skizzen in Erweiterter Realität. Mathematics [math]. Université Louis Pasteur - Strasbourg I, 2005. German. ⟨tel-00275264⟩

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