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Image-based Lagrangian Particle Tracking in bed-load experiments
Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions
at a relatively low cost. This manuscript describes an application of particle tracking velocimetry (PTV) to a bed-load experiment with lightweight
sediment. The key characteristics of the investigated sediment transport conditions were the presence of a covered flow and of a fixed rough
bed above which particles were released in limited number at the flume inlet. Under the applied flow conditions, the motion of the individual
bed-load particles was intermittent, with alternating movement and stillness terms. The flow pattern was preliminarily characterized by acoustic
measurements of vertical profiles of the stream-wise velocity. During process visualization, a large field of view was obtained using two actioncameras
placed at different locations along the flume. The experimental protocol is described in terms of channel calibration, experiment
realization, image pre-processing, automatic particle tracking, and post-processing of particle track data from the two cameras. The presented
proof-of-concept results include probability distributions of the particle hop length and duration. The achievements of this work are compared to
those of existing literature to demonstrate the validity of the protocol
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