FIGURE. RESULTS OF SUBMARINE DUNE MIGRATION ON THE 2010 BATHYMETRIC DATASET AT BANC DU FOUR, BRITTANY, FRANCE.

The workflow provide tools for detection and quantification of marine dunes displacements by comparing bathymetric surveys of a study area co-registered GeoTIFF datasets. The main steps of its processing chain consist in the tiling of geospatial raster data, the quantifying 2D displacement measurement, the merging of geospatial raster data and a spatio-temporal filtering of displacement time series.

The result of the workflow is three thematic map (raster) showing X and Y displacement fields and a correlation coefficient for a more accurate detection and quantification of dunes displacement. See teh Figure above.

To assess the performance and guide further development, this workflow has been compared against state‐of‐the art image matching methods in terms of quality of the results, scalability of the computation and the required amount of user interaction. Regarding the scalability of computation, even though the measurement of displacement rates with image correlation techniques is currently not time critical since in most cases data archives with a temporal frequency not below several months are analysed, MS4 workflow computational performance are in line with current solutions whereas the quality of the results are promising. The workflow offers an automatic treatment of a process that currently requires a manual selection of datasets, the quality of his results provide high perspectives for research activities.

The IQmulus algorithms have been tested on UBO Multi-beam sonar point clouds depicting the Banc du Four, full dataset cover approx. 100 sq.km, 2 x 120 million points (2 x 3,5 GB). The processing on the Fraunhofer cloud using took around 9 hours. The accuracy of the change detection was around 99% compared to Franzetti et al. methodology (thesis, 2014).