First sea trials of a laser aided three dimensional underwater image mosaicing technique

Georeferenced optical surveys of the seabed are obtained by composing mosaics of underwater images to allow scientists to study marine habitats, classify their features, quantify the population and measure the evolution over time. These are sought after tools but extremely complex to produce given the extent of the surfaces to map and the limited swath and range obtainable with standard diver or ROV operated image surveys. In this article we describe the development of an original technique based on the integration of laser light projection and digital image processing for the synthesis of georeferenced 3D optical maps of underwater scenes. For testing purposes a full scale payload prototype has been designed and integrated to IFREMER's experimental AUV (Autonomous Underwater Vehicle) Vortex. Promising results are shown using data collected during dedicated sea trials performed in the Mediterranean Sea.