2023_programme: Marine gas seep detection on synthetic aperture sonar data

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  • Session: 15. Towards Automatic Target Recognition. Detection, Classification and Modelling
    Organiser(s): Johannes Groen, Yan Pailhas, Roy Edgar Hansen, Jessica Topple and Narada Warakagoda
  • Lecture: Marine gas seep detection on synthetic aperture sonar data
    Paper ID: 2010
    Author(s): Austeng Andreas, Rindal Ole Marius Hoel, Blomberg Ann E. A., Hansen Roy E.
    Presenter: Austeng Andreas
    Abstract: Monitoring the oceans to detect gas leaks from oil and gas installations, pipelines, and CCS (carbon capture and storage) sites has received increased attention in recent years. Several sonar imaging modalities are suitable for the purpose, but so far, synthetic aperture sonar (SAS) imaging has proven unfit. This is because the echo from the seabed and the leak are mixed in such a way that it is difficult to distinguish them from one another.\nIn this work we investigate the spatial aperture coherence of seabed image pixels using the pulse echo version of the van Cittert-Zernike theorem. Contrary to conventional beamforming, which estimates the sum of the amplitude of the delayed element signals, the spatial aperture coherence measures the similarity between the delayed element signals. We suggest to calculate the spatial aperture coherence on delayed element signals with a retrospectively synthesized focus, i.e., where the SAS delayed data has been summed over transmit/pings, but where the receiver dimension has been kept. We show that low textured scenes have low spatial aperture coherence, while single scatterers and gas has higher spatial aperture coherence values. By examining the spatial extent of pixels with high-valued coherence, we present a method to identify gas leakage in SAS images. The proposed method is tested on simulated data, and on experimental SAS data collected above an abandoned well in the North Sea using a HUGIN autonomous underwater vehicle.
  • Corresponding author: Prof Andreas Austeng
    Affiliation: Department of Informatics, University of Oslo
    Country: Norway
    e-mail:

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