WAVE CELERITY FROM VIDEO IMAGING: A NEW METHOD

Video systems are emerging tools to monitor high frequency nearshore morphodynamics. Bathymetry can be inverted from surface wave celerity. We present here a new and robust method to estimate this celerity. The method is a time and space cross-correlation based on time-stack images. The celerity estimation is local, within a distance smaller than typical encountered wavelength and uses a time-domain correlation that integrates all wave effects within the duration of the time-stack. A validation is given from available in-situ data of the Pre-ECORS experiment. Global RMS error is lower than 0.2 m/s for the available period of comparison. Thus, the method seems to be well adapted to complex morphologies. Sources of error on the celerity estimation in the nearshore area are also investigated.