Remote Sensing (Feb 2021)

Sea State from Single Optical Images: A Methodology to Derive Wind-Generated Ocean Waves from Cameras, Drones and Satellites

  • Rafael Almar,
  • Erwin W. J. Bergsma,
  • Patricio A. Catalan,
  • Rodrigo Cienfuegos,
  • Leandro Suarez,
  • Felipe Lucero,
  • Alexandre Nicolae Lerma,
  • Franck Desmazes,
  • Eleonora Perugini,
  • Margaret L. Palmsten,
  • Chris Chickadel

DOI
https://doi.org/10.3390/rs13040679
Journal volume & issue
Vol. 13, no. 4
p. 679

Abstract

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Sea state is a key variable in ocean and coastal dynamics. The sea state is either sparsely measured by wave buoys and satellites or modelled over large scales. Only a few attempts have been devoted to sea state measurements covering a large domain; in particular its estimation from optical images. With optical technologies becoming omnipresent, optical images offer incomparable spatial resolution from diverse sensors such as shore-based cameras, airborne drones (unmanned aerial vehicles/UAVs), or satellites. Here, we present a standalone methodology to derive the water surface elevation anomaly induced by wind-generated ocean waves from optical imagery. The methodology was tested on drone and satellite images and compared against ground truth. The results show a clear dependence on the relative azimuth view angle in relation to the wave crest. A simple correction is proposed to overcome this bias. Overall, the presented methodology offers a practical way of estimating ocean waves for a wide range of applications.

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