Monitoring accropodes breakwaters using RGB-D cameras

Breakwaters are marine structures useful for the safe harbouring of ships and the protection of harbours from sedimentation and coasts from erosion. Breakwater monitoring is then a critical part of coastal engineering research, since it is crucial to know the state of a breakwater at any time in order to evaluate its health in terms of stability and plan restoration works. In this paper we present a novel breakwaters monitoring approach based on the analysis of 3D point clouds acquired with RGB-D cameras. The proposed method is able to estimate roto-translation movements of the Accropodes, building the armour layer of a breakwater, both under and above still water level, without any need of human interaction. We tested the proposed monitoring method with several laboratory experiments. The experiments consisted of the hitting of a scale model barrier by waves in a laboratory tank, aiming to asses the robustness of a particular configuration of the breakwater (that is, the arrangement of the Accropodes building the structure). During tests, several 3D depth maps of the barrier have been taken with a RGB-D camera. These point clouds, hence, have been processed to compute roto-translation movement, in order to monitor breakwater conditions and estimate its damage over time