Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLI-B1, 529-536, 2016
http://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLI-B1/529/2016/
doi:10.5194/isprs-archives-XLI-B1-529-2016
 
03 Jun 2016
A SYSTEMATIC COMPARISON OF DIRECT AND IMAGE-BASED GEOREFERENCING IN CHALLENGING URBAN AREAS
S. Cavegn1,2, S. Nebiker1, and N. Haala2 1Institute of Geomatics Engineering, FHNW University of Applied Sciences and Arts Northwestern Switzerland, Muttenz, Switzerland
2Institute for Photogrammetry, University of Stuttgart, Germany
Keywords: Image, Sequence, Stereo, Mobile Mapping, Direct, Integrated, Georeferencing, Sensor Orientation Abstract. Image-based mobile mapping systems enable an efficient acquisition of georeferenced image sequences, which can be used for geo-data capture in subsequent steps. In order to provide accurate measurements in a given reference frame while e.g. aiming at high fidelity 3D urban models, high quality georeferencing of the captured multi-view image sequences is required. Moreover, sub-pixel accurate orientations of these highly redundant image sequences are needed in order to optimally perform steps like dense multi-image matching as a prerequisite for 3D point cloud and mesh generation. While direct georeferencing of image-based mobile mapping data performs well in open areas, poor GNSS coverage in urban canyons aggravates fulfilling these high accuracy requirements, even with high-grade inertial navigation equipment. Hence, we conducted comprehensive investigations aiming at assessing the quality of directly georeferenced sensor orientations as well as the expected improvement by image-based georeferencing in a challenging urban environment. Our study repeatedly delivered mean trajectory deviations of up to 80 cm. By performing image-based georeferencing using bundle adjustment for a limited set of cameras and a limited number of ground control points, mean check point residuals could be lowered from approx. 40 cm to 4 cm. Furthermore, we showed that largely automated image-based georeferencing is capable of detecting and compensating discontinuities in directly georeferenced trajectories.
Conference paper (PDF, 1989 KB)


Citation: Cavegn, S., Nebiker, S., and Haala, N.: A SYSTEMATIC COMPARISON OF DIRECT AND IMAGE-BASED GEOREFERENCING IN CHALLENGING URBAN AREAS, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLI-B1, 529-536, doi:10.5194/isprs-archives-XLI-B1-529-2016, 2016.

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