The Marine Remote Sensing Group at the University of the Aegean, Department of Marine Sciences, in Greece recently conducted a successful experiment using drones to detect plastic waste in the Sea of Lesvos.
The project used European Satellites Sentinel-1, Sentinel-2, TeraSAR-X, and WorldView-3 to detect artificial marine litter targets. Sentinel-1 and Sentinel-2 are both part of the Copernicus Program satellite constellation conducted by the European Space Agency and are primarily used for land and sea monitoring, natural disasters mapping, sea ice observations, and ships detection. The TerraSAR-X imaging radar Earth observation satellite is a joint venture being carried out under a public-private partnership between the German Aerospace Center and EADS Astrium and WorldView-3 is a commercial Earth observation satellite owned by DigitalGlobe. The researchers also used four Marine Remote Sensing Group drones to precisely map the position and density of the plastics in specific spectral areas (visible, infrared, and thermal). Aerial photographs were also collected from a light aircraft flying at an average height. The three floating artificial targets, measuring 10 by 10 meters each, contained 3,600 1.5 liter plastic bottles of water, 185 plastic disposable bags, and 200 square meters of fishing nets.
The data received from the three sources was compared using image analysis, image processing algorithms, and satellite measurements in order to analyze the advantages and disadvantages of the different detecting systems. The targets were visible on all satellite data and will be the primary material for the creation of remote detection algorithms for plastic waste at sea.
The researchers state that the new drone technology will allow for data acquisition in remote areas with difficult access, that maps can be acquired at low cost and high resolution, that surface models can be generated at true scale for measuring distance, thickness and volumes, and that features from marine litters will be observed from the most favorable point of view.