Remote sensing of surf zone 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 have 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. This remote sensing approach provides data with excellent spatial coverage and spatial and temporal resolution. Additionally, the hardware needs are minimal and the system is quickly deployed, calibrated, and operational. In the present study, a phased approach was taken, with medium scale (domain similar to 50 m(2)) laboratory experiments being followed by a large scale (domain similar to 10(3)-10(4) m(2)) field test of the method. In the laboratory, reconstructed surface elevations were validated using a pressure sensor and demonstrated excellent agreement In the field, measured wave heights and periods were found to agree well with available buoy data. (C) 2010 Elsevier B.V. All rights reserved.