In-situ measurement of river-bed sediment porosity using Structure-from-Motion image analysis

摘要: Abstract Due to the difficulty and inaccuracy of in-situ porosity measurement methods in fluvial deposits, knowledge about spatial variation river bed is limited. The objective this study was develop a new accurate method improve facilitate deposits. For purpose, Structure-from-Motion (SfM) photogrammetry-based applied determine total volume (Vt) sampling pit. then combined with solid fraction (Vs) measured by water displacement calculate porosity. Several sets experiments were carried out evaluate systematic stochastic uncertainties method. Combination Vt Vs using standard error propagation showed absolute uncertainty be less than 0.01. Compared existing methods, SfM increases accuracy significantly strongly speeds up measurements, as it independent from field calibration initial sediment sample stabilization.