Image-based measurement system for regular waves in an offshore basin

This paper presents the application of the shape-from-reflection technique to measure the free surface in an indoor wave basin. A well-known reflectance model is applied to model the relation between the image irradiance and water surface slopes which are then used to estimate the wave amplitude. An experimental setup is proposed, designed to grant appropriate boundary conditions to the application of the reflectance model, even under general laboratory illumination. The method is restricted to unidirectional regular waves since the focus here is to understand and to verify the validity of the hypotheses of the model; the results presented are therefore preliminary. The extension of the method for irregular waves and more practical uses are discussed in the final section.