Towards harmonization of image velocimetry techniques for river surface velocity observations

Since the turn of the 21st Century, image based velocimetry techniques have become an increasingly popular approach for determining open-channel flow in a range of hydrological settings across Europe, and beyond. Simultaneously, a range of large-scale image velocimetry algorithms have been developed, equipped with differing image pre-processing, and analytical capabilities. Yet in operational hydrometry, these techniques are utilised by few competent authorities. Therefore, imagery collected for image velocimetry analysis, along with validation data is required both to enable inter-comparisons between these differing approaches and to test their overall efficacy. Through benchmarking exercises, it will be possible to assess which approaches are best suited for a range of fluvial settings, and to focus future software developments. Here we collate, and describe datasets acquired from six countries across Europe and Asia, consisting of videos that have been subjected to a range of pre-processing, and image velocimetry analysis (Perks et al., 2019, https://doi.org/10.4121/uuid:34764be1-31f9-4626-8b11-705b4f66b95a). Validation data is available for 12 of the 13 case studies presented enabling these data to be used for validation and accuracy assessment

Data on the harmonization of image velocimetry techniques, from seven different countries

Here, we present a range of datasets that have been compiled from across seven countries in order to facilitate image velocimetry inter-comparison studies. These data have been independently produced for the primarily purposes of: (i) enhancing our understanding of open-channel flows in diverse flow regimes; and (ii) testing specific image velocimetry techniques. These datasets have been acquired across a range of hydro-geomorphic settings, using a diverse range of cameras, encoding software, controller units, and with river velocity measurements generated as a result of differing image pre-processing and image processing software