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Remote Sensing of Nearshore Currents using Coastal Optical Imagery
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  • Journal title : Ocean and Polar Research
  • Volume 37, Issue 1,  2015, pp.11-22
  • Publisher : Korea Institute of Ocean Science & Technology
  • DOI : 10.4217/OPR.2015.37.1.011
 Title & Authors
Remote Sensing of Nearshore Currents using Coastal Optical Imagery
Yoo, Jeseon; Kim, Sun-Sin;
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 Abstract
In-situ measurements are labor-intensive, time-consuming, and limited in their ability to observe currents with spatial variations in the surf zone. This paper proposes an optical image-based method of measurement of currents in the surf zone. This method measures nearshore currents by tracking in time wave breaking-induced foam patches from sequential images. Foam patches in images tend to be arrayed with irregular pixel intensity values, which are likely to remain consistent for a short period of time. This irregular intensity feature of a foam patch is characterized and represented as a keypoint using an image-based object recognition method, i.e., Scale Invariant Feature Transform (SIFT). The keypoints identified by the SIFT method are traced from time sequential images to produce instantaneous velocity fields. In order to remove erroneous velocities, the instantaneous velocity fields are filtered by binding them within upper and lower limits, and averaging the velocity data in time and space with a certain interval. The measurements that are obtained by this method are comparable to the results estimated by an existing image-based method of observing currents, named the Optical Current Meter (OCM).
 Keywords
digital optical imagery;surf zone;nearshore currents;remote sensing;wave-induced foam;
 Language
Korean
 Cited by
 References
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