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@article{Cao:2025:10.1109/JOE.2024.3467312,
author = {Cao, R and Padilla, EM and Fang, Y and Callaghan, A},
doi = {10.1109/JOE.2024.3467312},
journal = {IEEE Journal of Oceanic Engineering},
pages = {204--212},
title = {Identification of the free surface for unidirectional non-breaking water waves from side-view digital images},
url = {http://dx.doi.org/10.1109/JOE.2024.3467312},
volume = {50},
year = {2025}
}
TY - JOUR
AB - We present a semi-automated image processingmethod, the continuous maximum gradient (CMG) method, foridentifying the air–water interface in side-view digital images ofunidirectional water waves in a glass-walled laboratory wave flume.In a manner similar to Canny edge detection, CMG exploits gradi ents in pixel intensity to identify the free surface, but also enforcesan additional streamline constraint. This latter step is necessaryto exclude signals from other features, such as wave gauges andwater droplets on the glass, which also exhibit large intensitygradients. To demonstrate the performance and accuracy of CMG,we first compare its detection results with independent wave gaugemeasurements. The maximum difference in total spectral variancewas found to be approximately 4%, while quantitative error metricsfrom a regression analysis yielded an R2 value of 0.997 for thesurface elevation time-series. We also compare the CMG detectionresults with imagery data from existing literature where excellentvisual agreement is observed, confirming the broad applicability ofthe CMG method. The employment of CMG facilitates free surfacemeasurements at a very high resolution (order of millimeters)which is essential for capturing the spatio-temporal wave-fieldevolution and obtaining instantaneous measurement of local waveshape.
AU - Cao,R
AU - Padilla,EM
AU - Fang,Y
AU - Callaghan,A
DO - 10.1109/JOE.2024.3467312
EP - 212
PY - 2025///
SN - 0364-9059
SP - 204
TI - Identification of the free surface for unidirectional non-breaking water waves from side-view digital images
T2 - IEEE Journal of Oceanic Engineering
UR - http://dx.doi.org/10.1109/JOE.2024.3467312
UR - https://ieeexplore.ieee.org/abstract/document/10752837?casa_token=bCZMj3zoYqIAAAAA:KgB0f1JGlSoLlX0Nwq5tAfoLX7J67WOIFX_YKhU9Et9QVrIZd1Zc1ItZrRa2CrWX1XyL-56C
VL - 50
ER -
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