Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation
Nearshore bathymetry is key to most oceanographic studies and coastal engineering works. This work proposes a new methodology to assess nearshore wave celerity and infer bathymetry from video images. Shoaling and breaking wave patterns were detected on the Timestacks distinctly, and wave celerity wa...
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| Format: | Article |
| Language: | English |
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MDPI AG
2025-07-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/17/13/2274 |
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| author | Umberto Andriolo Alberto Azevedo Gil Gonçalves Rui Taborda |
| author_facet | Umberto Andriolo Alberto Azevedo Gil Gonçalves Rui Taborda |
| author_sort | Umberto Andriolo |
| collection | DOAJ |
| description | Nearshore bathymetry is key to most oceanographic studies and coastal engineering works. This work proposes a new methodology to assess nearshore wave celerity and infer bathymetry from video images. Shoaling and breaking wave patterns were detected on the Timestacks distinctly, and wave celerity was estimated from wave trajectories. The wave type separation enabled the implementation of specific domain formulations for depth inversion: linear for shoaling and non-linear for breaking waves. The technique was validated over a rocky bottom using video acquisition of an online streaming webcam for a period of two days, with significant wave heights varying between 1.7 m and 3.5 m. The results were corroborated in comparison to ground-truth data available up to a depth of 10 m, yielding a mean bias of 0.05 m and a mean root mean square error (RMSE) of 0.43 m. In particular, RMSE was lower than 15% in the outer surf zone, where breaking processes occur. Overall, the depth-normalized RMSE was always lower than 20%, with the major inaccuracy due to some local depressions, which were not resolved. The developed technique can be readily applied to images collected by coastal monitoring stations worldwide and is applicable to drone video acquisitions. |
| format | Article |
| id | doaj-art-1cee1f0dc6434dbb96de2ec69b843759 |
| institution | DOAJ |
| issn | 2072-4292 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj-art-1cee1f0dc6434dbb96de2ec69b8437592025-08-20T03:16:42ZengMDPI AGRemote Sensing2072-42922025-07-011713227410.3390/rs17132274Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity EstimationUmberto Andriolo0Alberto Azevedo1Gil Gonçalves2Rui Taborda3INESC Coimbra, Department of Electrical and Computer Engineering, Polo II, 3030-790 Coimbra, PortugalNational Laboratory for Civil Engineering, Hydraulics and Environment Department, LNEC, 1700-066 Lisbon, PortugalINESC Coimbra, Department of Electrical and Computer Engineering, Polo II, 3030-790 Coimbra, PortugalInstituto Dom Luiz, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, PortugalNearshore bathymetry is key to most oceanographic studies and coastal engineering works. This work proposes a new methodology to assess nearshore wave celerity and infer bathymetry from video images. Shoaling and breaking wave patterns were detected on the Timestacks distinctly, and wave celerity was estimated from wave trajectories. The wave type separation enabled the implementation of specific domain formulations for depth inversion: linear for shoaling and non-linear for breaking waves. The technique was validated over a rocky bottom using video acquisition of an online streaming webcam for a period of two days, with significant wave heights varying between 1.7 m and 3.5 m. The results were corroborated in comparison to ground-truth data available up to a depth of 10 m, yielding a mean bias of 0.05 m and a mean root mean square error (RMSE) of 0.43 m. In particular, RMSE was lower than 15% in the outer surf zone, where breaking processes occur. Overall, the depth-normalized RMSE was always lower than 20%, with the major inaccuracy due to some local depressions, which were not resolved. The developed technique can be readily applied to images collected by coastal monitoring stations worldwide and is applicable to drone video acquisitions.https://www.mdpi.com/2072-4292/17/13/2274coastal hydrodynamicsbeachremote sensingvideo monitoringTimestack images |
| spellingShingle | Umberto Andriolo Alberto Azevedo Gil Gonçalves Rui Taborda Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation Remote Sensing coastal hydrodynamics beach remote sensing video monitoring Timestack images |
| title | Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation |
| title_full | Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation |
| title_fullStr | Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation |
| title_full_unstemmed | Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation |
| title_short | Nearshore Depth Inversion Bathymetry from Coastal Webcam: A Novel Technique Based on Wave Celerity Estimation |
| title_sort | nearshore depth inversion bathymetry from coastal webcam a novel technique based on wave celerity estimation |
| topic | coastal hydrodynamics beach remote sensing video monitoring Timestack images |
| url | https://www.mdpi.com/2072-4292/17/13/2274 |
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