Guilhem Marre

Ph.D. student 2017- 2020 at the University of Montpellier(Funding CIFRE)

Co-supervised byJulie Deterand Sandra Luque (IRSTEA – UMR TETIS)

Development of photogrammetry and image processing methods for the monitoring of marine habitats and underwater infrastructures

The Marine Strategy Framework Directive (2008) extended the conservation efforts of the Water Framework Directive (2000) to the marine realm, by committing European countries to achieve a good environmental status of coastal waters by 2020. It is about monitoring the status of marine ecosystems and defining an integrated management to allow a sustainable use of marine resources. In this context,Andromède Océanologiehas developed several networks for the monitoring of the two richest and most sensitive Mediterranean marine habitats, the Posidonia meadows and the coralligenous reefs, and has worked for years on the development of innovative methods for the study of benthic communities. Photogrammetry, this science initially developed for the measurement of objects with pictures taken from different locations, has been booming for a few years along with the computing power. From now on, it enables reproducing whole landscapes in three dimensions with an very high precision. Yet, the difficulty to access the underwater world considerably restrains the amount of data collected. Photogrammetry could then enable, from a relatively short acquisition time, to reproduce, study and monitor in time a complex marine habitat. This phD project has 3 objectives: improve and standardize the photographic acquisition for the production of 3D models, develop indicators based on the models (diversity and status of coralligenous reefs, fine-scale seagrass meadows cartography,…) and finally integrate those indicators to the monitoring networks carried out byAndromède Océanologie.