Postdoctoral Qualification HABIL-2005-02

BibliographyHaala, Norbert: Multi-Sensor-Photogrammetrie - Vision oder Wirklichkeit?.
University of Stuttgart : Collaborative Research Center SFB 627 (Nexus: World Models for Mobile Context-Based Systems), Postdoctoral Qualification (2005).
103 pages, german.
CR-SchemaJ.0 (Computer Applications General)
Abstract

The application of multi-sensor systems for photogrammetric data collection has reached considerable interest. Within this habilitation treatise, their potential for spatial information collection is discussed exemplarily in the context of different application scenarios. This includes the increased degree of automation, which can be achieved for standard data processing as well as the chance to open up new areas of application for photogrammetric products and techniques. The combination of multiple sensors is first demonstrated by the example of integrated GPS/inertial systems, which are used to provide the transformation of the collected imagery to a reference coordinate system. This direct geoereferencing is applied for the geometric evaluation of airborne imagery alternatively to the indirect approach of image orientation based on standard aerial triangulation. Within the first part of the thesis the accuracy potential and different application scenarios of direct georeferencing are discussed. Another main point of interest is the suitable integration of the directly measured orientation parameters with the photogrammetric evaluation process. The combination of direct georeferencing and aerial triangulation is an important prerequisite for the calibration of the overall system. Additionally, the integrated processing allows to use the different sensors as complementary sources of information and helps to provide optimal solutions with respect to different application scenarios and accuracy requirements. The potential of integrated GPS/inertial systems is discussed exemplarily using data of digital airborne cameras. These systems facilitate the acquisition of multispectral images at high spatial resolution. Complementary to these sensors, airborne laser scanning provides an alternative data source, which is advantageous if the automatic collection of thematic object information is aspired. Compared to the use of standard panchromatic aerial images, especially the combination of image and height data is beneficial for the automatic reconstruction of topographic objects. Within the thesis this is demonstrated by a process aiming on the combined classification of built-up areas. The advantages of integrating height and image data are also discussed by the example of a combined segmentation process, which aims on the extraction of three-dimensional geometric primitives like straight lines and planar regions. Such an extraction of reliable and accurate geometric primitives is an important preprocessing step for 3D object reconstruction. For this reason, the segmentation combines the advantages of both data sources, the relatively simple interpretation of height data due to the restriction to geometric information on the one hand and the high density of information available from aerial images on the other hand. In addition to primary data sources as they are provided from different photogrammetric sensors, GIS data is frequently already available for a number of application scenarios. In the figurative sense, the use of GIS data can also be interpreted as the integration of a additional sensor data. The availability of GIS during automated collection of topographic objects is especially useful, since GIS provides information from already interpreted data. Within the thesis the advantages of use of existing GIS is demonstrated by processes aiming on the reconstruction of 3D building models from dense height models. Within the process given outlines of the buildings are integrated in order to support the segmentation process and to detect the underlying structure of the extracted geometric primitives. If improved methods of photogrammetric data collection are available new markets for new products can be opened. One example is the increasing demand for 3D city models, which are frequently applied in the context of virtual landscape visualisation. These 3D city models can also be integrated to a suitable multi-sensor, multi-data system in order to allow for a GIS-based georeferencing of terrestrial images. Such an automatic registration of terrestrial images to a virtual 3D model of the environment is for example required during update or extension of the visible building models. As it is discussed in the final part of the thesis, the result of this orientation process can also be used for the presentation of object related information in the context of location based services.

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Department(s)Universität Stuttgart, Institut für Photogrammetrie (ifp)
Project(s)SFB-627, C4 (Universität Stuttgart, Institut für Photogrammetrie (ifp))
SFB-627, C1 (Universität Stuttgart, Institut für Photogrammetrie (ifp))
Entry dateMay 26, 2006
   Publ. Computer Science