A method for extracting surface flow velocities and discharge volumes from video images in laboratory

The lack of hydrological data has been identified as one of the major obstacles facing the effective evaluation of hydraulic and hydrological interventions in the field. Traditional methods of data collection have proven to be generally expensive and particularly risky under high flow conditions. A method for quantifying hydrodynamic variables, such as surface flow velocity and discharge volume was developed in a laboratory setting using video images. This method explores several innovative image analysis techniques, specifically the Image Variance (IV) and Threshold Segmentation with Path Discretization (TSPD), where the basics steps comprise image capture, rectification and data extraction. Measurements obtained from conventional instruments and data extracted from video images were compared and exhibited less than 2.5% difference. It can be concluded that under laboratory conditions it is possible to obtain reliable velocities and discharges from video techniques, without being in contact with the flow. (C) 2013 Elsevier Ltd. All rights reserved.