How do you detect almost invisible objects in real-time?
Yesterday, our colleague Steffen Yader Stadler presented our lessons learned after the first three months of the project GhostNetBusters.
Here are some insights:
1. Differentiating between seafloor and objects at the edge of the water column seems to be difficult for most bottom line detectors.
While the human operator is aware that the bottom hasn’t risen several metres, machine learning algorithms need to be taught to recognize this sudden rise as an object of interest.
2. Objects in the gain range are “just” invisible to the human eye.
As the range of the sonar signal increases, the increasing gain makes human annotation a serious problem because objects are hard to see on the image. However, since we know where the object should be, through geo-referencing and active data generation with our partners, we can train our algorithms to see beyond the acoustic noise and detect the invisible.
3. A side-scan map without water columns helps to distinguish between known and new objects.
Wrecks, large boulders or seaweed do not change position underwater. Lost fishing gear, on the other hand, will move, wraps itself around these structures or crawls into the seabed. By correcting for slant range, we are able to create a holistic map of the seafloor. Nothing extraordinary, but quite useful.
4. At a certain distance, the beams overlap and cover the same area twice.
While the quality of the signal decreases dramatically with distance, the spread of the beam results in multiple coverage of the area of interest. Through inverse modelling, we expect to gather more information about objects hidden in the noise, allowing them to be detected despite their invisibility.
We look forward to sharing more exciting insights into the progress of the project in the coming months.
The project is carried out by GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel and sonoware GmbH, funded by the AI fund of the Land Schleswig-Holstein.
Maritimes Cluster Norddeutschland e. V.
Wirtschafts- und Wissenschaftspark mariCUBE
Warner Brueckmann
Mia Schumacher