The Environmental Fluid Mechanics/Hydrology Series

Remote Sensing of Coastal Waves Using Stereo Imaging

The measurement of water wave characteristics, such as wavelength and wave height, in the surf zone is important for monitoring, prediction of erosion, and numerical model calibration. Traditional methods of measuring wave heights have either been limited to a small number of points or required contact with the water. An experimental study of the remote sensing of water wave elevations, through the application of stereo photogrammetry, is presented. This method uses two spatially offset cameras, with overlapping fields of view, to determine water surface elevation over a large spatial extent. A phased approach was taken, with medium scale laboratory experiments being followed by a large scale field test of the method. In the laboratory, reconstructed surface elevations were validated using a pressure sensor and the stereo image reconstructions of the water surface showed excellent agreement. In the field, the measured wave heights & periods showed good agreement with nearby available buoy data.

Overall, the method proved very successful at measuring nearshore waves and appears to hold considerable promise as a robust remote sensing technique. The advantages of this approach are that it provides excellent spatial & temporal coverage, has fairly minimal hardware needs, and that the system is quickly deployed, calibrated and operational.