The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Citation
Articles | Volume XLII-2/W18
https://doi.org/10.5194/isprs-archives-XLII-2-W18-1-2019
https://doi.org/10.5194/isprs-archives-XLII-2-W18-1-2019
29 Nov 2019
 | 29 Nov 2019

IMPROVEMENT AND PERFORMANCE EVALUATION OF A SYSTEM FOR MONITORING ROTATIONS AND DISPLACEMENTS OF BRIDGES BASED ON LASER POINTER AND DIGITAL PHOTOGRAMMETRY

G. Artese

Keywords: Laser Pointer, Digital Photogrammetry, Image Processing, Structure Monitoring

Abstract. A system for monitoring rotations and displacements of bridges based on laser pointer and digital photogrammetry is described. The system uses three common laser pointers and image processing. The inclination of the elastic line is measured by analysing the individual frames of an HD video of the laser beam footprint projected onto a flat target. The methodology, able to conjugate a high precision, low cost, and easiness of use, is an evolution of a method developed at University of Calabria, Italy. The use of three laser pointers allows to improve the performance of the previous method, obtaining both displacements and rotations at a generic point of the bridge deck, and deriving the transverse rotation of the deck cross section. The investigated method exploits the laser pointers’ property to provide a steady pointing direction, a long-range and a high-brightness visible imprint. The method and the results of an experimental test are described and discussed.