Equipment

The Université de Nantes Underwater stereo camera consists of two GoPro cameras, two waterproof artificial lights, and an adjustable measuring stick. The two GoPro cameras simultaneously photograph a scene from slightly different perspectives. By taking photographs of a target from at least two different vantage points, 3D information of the scene becomes encoded in the imagery.

Services

This device is intended to facilitate inspections of all offshore and marine structures including marine renewable energy devices.

Example of MRE applications

This device can be used for quantifying cracks and visible damage forms, such as corrosion, which appear on the surface of MRE structures. However, to leverage the full potential of this device, we should look at 3D imaging. The 3D information that is captured by this device can be used for volumetric measurements, documentation, and presentation to the general public.

One specific application concerns measuring the shape of structural members that have been colonized by marine growth. Marine growth significantly increases the diameter and roughness of structural members. This introduces several problems; most notably, it increases drag forces and creates unpredictable hydrodynamic instabilities. These factors often cause a loss in structural performance and reliability, leading to shortened lifespans for MRE structures.

Owners/operators of these structures, therefore, have a keen interest in monitoring the progression of marine growth so that they can choose the best times to carry out costly cleaning regimes, and so that they have more reliable estimates of the loading on a structure. This is useful when assessing a structure’s eligibility for requalification schemes, which ultimately, can prolong a structure’s in-service life. The diameter and roughness vary around and among structural components, and require full 3D shape of the marine growth to be computed.