Noise barriers are constructed, measured and used in noise models to establish, for technical and legal purposes, the way or extent that noise/sound pollution will affect the environment in their proximity.
In this context, this paper explores the applicability of close-range photogrammetry for the measurement of large concrete noise barriers located along a busy motorway. Close range photogrammetry was considered as this measuring technique provides for a noncontact, inexpensive, safer and practical measurement option.
This research was divided into two photogrammetry projects. In the first project, photogrammetry techniques were employed in the geometry measurement of a simple concrete noise barrier. The barrier was measured and evaluated according to routine noise barrier inspection guidelines.
PhotoModeler, a consumer-grade photogrammetry software program, was used to process the digital stereo images needed to extract the 3D parameters of the structure. The images were taken using a GPS enabled digital camera integrating a 3D compass.
Comparison between photogrammetric and as constructed measurements carried out with a precise surveying total station instrument showed minor differences, with the percentage relative error ranging from 0.04% to 1.16%.
The second project investigated the feasibility of the GPS enabled digital camera as a stand alone measuring tool for the direct geo-referencing of the noise barrier. The results of this second study showed that the photogrammetry measurements differed from the more precise surveying measurements by 3.15% to 9.00%.