Spatial-temporal measurement of waves in laboratory based on binocular stereo vision and image processing

Abstract

Acquisition of wave field data is essential for hydrodynamics studies. Current studies show deficiencies in the spatial measurement of wave fields in the laboratory, and a more efficient method is urgently needed. A stereo imaging method was proposed for the spatial-temporal measurement of waves in the laboratory based on binocular stereo vision and digital image processing. Then, a series of regular and focused waves were simulated in a wave flume to examine the feasibility and reliability of the method by comparison with the measurements by wave probes. Floating particles were evenly sprinkled on the water surface as the representation of the water-air interface, providing texture features for wave surface images and allowing the realization of dense reconstruction. Synchronized cameras provided the synchronized stereo pairs sequence for each wave, and temporal reconstruction was achieved by processing frame by frame. The 4D spatial-temporal volume for every wave could be constructed. Subsequently, spatial slices of the volume obtained the instantaneous profiles of the wave field in different directions. Temporal slices obtained the wave time series at a fixed point, which were compared with the measurements of the standard resistive probe to verify the accuracy. The results showed that the proposed method was capable of measuring the spatial-temporal field of waves efficiently and precisely and offered the potential to measure more complex wave fields in nonlinear wave-structure interactions.