2134/24311 Edgar Ferreira Edgar Ferreira Jim Chandler Jim Chandler Rene Wackrow Rene Wackrow Koji Shiono Koji Shiono Automated extraction of free surface topography using SfM-MVS photogrammetry Loughborough University 2017 Eco-hydraulics Free surface measurement Laboratory studies SfM-MVS photogrammetry Built Environment and Design not elsewhere classified 2017-03-06 13:22:23 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Automated_extraction_of_free_surface_topography_using_SfM-MVS_photogrammetry/9448634 This paper describes a spatial measurement technique to measure the free surface of natural fluid flows in laboratory applications. This effective solution is based on “Structure-from- Motion/Multi-view Stereo” (SfM-MVS) photogrammetry and is capable of reconstructing water surface morphology, both at an instant and with a high spatial resolution. The efficiency and accuracy of the method is dependent upon the acquisition of high quality imagery (i.e. sharply focussed, no motion blur) with appropriate multi-frame camera coverage and configuration, and data processing must utilise appropriate camera calibration data. The potential of the technique for developing hydraulic understanding is demonstrated using two contrasting approaches. First, the water surface behind a living vegetation element is analysed along a single transect. Second, the full three-dimensional characteristics of the captured water surfaces are examined using statistical methods which demonstrate surface dissimilarity between vegetated and non-vegetated cases. The technique is transferable to real-world field sites.