Thanh-Nhan Nguyen, Yun-tae Kim
Evaluating scour around a hollow artificial reef (HAR) is inherently challenging due to its porous structure, complex geometry, and the combined influence of multiple environmental factors, including both hydrodynamic and geotechnical properties. In this study, a combination of laboratory experiments, a monocular vision system, and image processing techniques was employed to investigate key scour characteristics, including scour depth, scour volume, the extent of the scour region, and morphological changes of the HAR under steady flow conditions. A novel workflow based on a set of freely available software packages and a monocular vision system was developed to generate a high-density and high-accuracy point cloud of the seabed surface. By implementing higher-order panel element generation, a 3D scour surface model was reconstructed, enabling detailed accuracy assessments of scour characteristics. From this approach, a highly accurate digital elevation model (DEM) of the seabed morphology was produced, yielding a correlation coefficient ( R 2 ) of 0.9904 when compared with ground survey data obtained via a laser distance sensor system. Furthermore, two empirical equations were proposed to predict the spatial extent of the scour region, specifically in the front and side directions, based on flow intensity. These equations achieved high correlation coefficients of R 2 = 0.9170 and R 2 = 0.8723, respectively. A detailed comparison with previous studies was conducted to validate the proposed methodology. The results of this research provide valuable insights for the design of HARs and for developing effective scour mitigation strategies.