Photogrammetrische Aufnahme und 3D-Punktewolken-Prozessierung einer Ortsbrust im maschinellen Tunnelvortrieb und deren Vergleich mit einem Laserscan
Research output: Thesis › Master's Thesis
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Abstract
In this work, the image linking of photogrammetrically recorded ring-shaped partial sections, the so-called recorded tracks of a tunnel face in continuous tunnel construction, carried out with image-processing software, was investigated. For quality control purposes particular attention was paid to the external accuracy of the reconstructed tunnel face in addition to internal accuracy. The photogrammetric images were taken in the northern access tunnel of the second tube of the Gotthard Road Tunnel with a photogrammetric system, which was developed by the Montanuniversität and the company Geodata MT GmbH. The photogrammetric system was developed as part of a research collaboration and is used for the digital monitoring of the tunnel face in mechanized tunnel constructions. The results of the scientific work showed that highquality images were obtained by carefully setting the recording parameters, which didn¿t impair the image processing and image linking. However, the realization of a sufficient lateral image overlap proved to be problematic due to the fixed camera mounting positions, which were dependent on the specific cutting disk arrangement on the cutting head. As a result, no image links could be established between the recorded tracks during the image processing procedure. As a result, the simultaneous calibration resulted in orientation parameters based on an incompletely linked image array, which led to independent recorded tracks with high internal accuracy. By determining the distance to a laser scan, an insufficient external accuracy of the photogrammetrically processed reconstruction of the tunnel face was determined. The results of the evaluation of the external accuracy made it possible to see that the correction of the camera orientation was not optimally possible, whereby these could be reconstructed with a high internal accuracy, but negatively influenced the external accuracy. To improve the linking of individual recorded tracks, solutions such as optimizing the overlapping of the recorded tracks and the camera alignment were proposed. The progress achieved not only enables more efficient use of the photogrammetric system, but also eliminates the additional processing step of coregistering the recording tracks.
Details
Translated title of the contribution | Photogrammetric imaging and 3D-pointcloud-processing of a tunnelface in mechanized tunnelling and its comparison to a laser scan |
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Original language | German |
Qualification | Dipl.-Ing. |
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Award date | 22 Mar 2024 |
DOIs | |
Publication status | Published - 2024 |