-
Gereb, Gabor; Austeng, Andreas; Hansen, Roy Edgar & Birkenes Lønmo, Tor Inge
(2024).
Resolution of adaptive beamformers.
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Gereb, Gabor; Austeng, Andreas; Hansen, Roy Edgar & Birkenes Lønmo, Tor Inge
(2023).
Performance analysis of adaptive beamformers in surveying pipelines by multi-beam echo sounders.
-
(2023).
Long-range interferometric synthetic aperture sonar.
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Orescanin, Marco; Harrington, Brian; Olson, Derek R.; Geilhufe, Marc; Hansen, Roy Edgar & Warakagoda, Narada Dilp
(2023).
Uncertainty quantification with deep learning through variational inference with applications to synthetic aperture sonar.
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Geilhufe, Marc; Olson, Derek R.; Hansen, Roy Edgar & Synnes, Stig Asle Vaksvik
(2023).
A wavelet shrinkage approach to detect candidate point scatterers in synthetic aperture sonar images for resolution estimation.
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Orescanin, Marko; Harrington, Brian; Olson, Derek R.; Geilhufe, Marc; Hansen, Roy Edgar & Warakagoda, Narada Dilp
(2023).
A Study on the Effect of Commonly Used Data Augmentation Techniques on Sonar Image Artifact Detection Using Deep Neural Networks.
-
(2023).
Challenges in synthetic aperture sonar imaging of shipwrecks for change detection.
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Zhang, Xuebo; Heald, Gary; Lyons, Anthony P.; Hansen, Roy Edgar & Hunter, Alan J.
(2023).
Guest editorial: recent advances in synthetic aperture sonar technology.
Electronics Letters.
ISSN 0013-5194.
59(14).
doi:
10.1049/ell2.12881.
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Crawford, Anna M; Hansen, Roy Edgar; Johnson, Sean; King, Jonathan L.; Midtgaard, Øivind & Sæbø, Torstein Olsmo
(2022).
Improvements to change detection tools for SAS images,
OCEANS 2022 Hampton Roads.
IEEE.
ISSN 978-1-6654-6809-1.
-
(2022).
Phase ambiguities in Synthetic Aperture Sonar Interferometry,
OCEANS 2022 Hampton Roads.
IEEE.
ISSN 978-1-6654-6809-1.
-
Crawford, Anna M; Hansen, Roy Edgar; Johnson, Sean; King, Jonathan L.; Midtgaard, Øivind & Sæbø, Torstein Olsmo
(2022).
Improvements to change detection tools for SAS images.
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Lorentzen, Ole J.; Hansen, Roy Edgar; Sæbø, Torstein Olsmo; Hunter, Alan Joseph; Synnes, Stig Asle Vaksvik & Geilhufe, Marc
(2022).
Hypothesis testing of 3D object shapes for synthetic aperture sonar interferometry.
-
(2022).
Investigation of layover in interferometry.
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Sæbø, Torstein Olsmo; Hansen, Roy Edgar & Lyons, Anthony P.
(2022).
Synthetic aperture sonar multi-aspect differential interferometry for detection of internal waves.
-
(2022).
Phase ambiguities in Synthetic Aperture Sonar Interferometry.
-
(2022).
Benefits and Limitations in MIMO Synthetic Aperture Sonar.
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Hansen, Roy Edgar; Geilhufe, Marc; Synnes, Stig Asle Vaksvik; Sæbø, Torstein Olsmo & Thon, Stine Hverven
(2022).
Detection of Coherent Scatterers in Synthetic Aperture Sonar Using Multilook Coherence.
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Gereb, Gabor; Hansen, Roy Edgar; Austeng, Andreas; Lønmo, Tor Inge Birkenes; Näsholm, Sven Peter & Rindal, Ole Marius Hoel
(2022).
Ultrasound Beamformer Benchmarking Pipeline.
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Gereb, Gabor; Hansen, Roy Edgar; Lønmo, Tor Inge Birkenes; Näsholm, Sven Peter; Austeng, Andreas & Rindal, Ole Marius Hoel
(2022).
Improving Sonar Surveying of Subsea Cables and Pipelines with Adaptive Beamforming.
Show summary
Background, Motivation and Objective
Safe and efficient transportation of offshore energy requires well-maintained underwater infrastructure, no matter if the energy source is fossil, wind, sun, or wave. Subsea cables and pipelines can be efficiently surveyed using sonar systems mounted on surface or underwater vehicles. Adaptive array signal processing methods are increasingly explored to improve image quality and detection or estimation accuracy in specific survey scenarios. However, adaptive methods can be sensitive to the context they are used in. Therefore, choosing the right beamforming approach from the available candidates requires extensive testing in various scenarios, which is often not feasible out at sea.
Statement of Contribution/Methods
Realistic simulation of complex underwater scenarios has been previously demonstrated using the Field II Ultrasound Simulation Program in combination with the open access package UltraSound ToolBox (USTB). We use Field II to create digital twins of water column images from pipeline surveys, and then modify parameters such as the layout, depth, and SNR to extend the scope of testing. We add multiple realizations of random noise to the signal and then use USTB to beamform the data with different techniques. On the beamformed data we perform estimation of multiple parameters such as the position and size of the pipe and the seabed depth around it. Finally, using the known ground truth of the model, we compare the bias and variance of the estimations made using images reconstructed by different beamformers.
Results/Discussion
Following on the results of previous studies demonstrating the benefits of adaptive beamforming in sonar bathymetry, we present a benchmark study of adaptive beamforming techniques such as Low Complexity Adaptive (LCA) and Capon Minimum Variance (MVDR). Comparison with the Coherence Factor (CF) method is made as well. We use Delay-and-Sum (DAS) as a reference with various apodizations. We provide quantitative performance assessment based on the statistical distribution of the estimations with reference to the ground truth in different scenarios.
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Lønmo, Tor Inge Birkenes; Austeng, Andreas & Hansen, Roy Edgar
(2022).
Adaptive Beamforming and Autocalibration for Swath Sonars.
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Lønmo, Tor Inge Birkenes; Austeng, Andreas & Hansen, Roy Edgar
(2022).
Adaptive Beamforming and Autocalibration for Swath Sonars.
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Rindal, Ole Marius Hoel; Näsholm, Sven Peter; Hansen, Roy Edgar & Austeng, Andreas
(2022).
Compensating Dynamic Range Alterations from Adaptive Beamforming using Histogram Matching.
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Rindal, Ole Marius Hoel; Näsholm, Sven Peter; Hansen, Roy Edgar & Austeng, Andreas
(2022).
Image Enhancement Using Capon Minimum Variance Adaptive Beamforming in Synthetic Aperture Sonar.
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Austeng, Andreas; Näsholm, Sven Peter; Hansen, Roy Edgar & Rindal, Ole Marius Hoel
(2022).
Spatial Aperture Coherence with Synthetic Transmit Focusing in SAS.
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Gereb, Gabor; Hansen, Roy Edgar; Lønmo, Tor Inge Birkenes; Näsholm, Sven Peter & Austeng, Andreas
(2022).
Underwater pipeline detection and localisation using multibeam echo sounder in a resolution limited case.
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Gereb, Gabor; Hansen, Roy Edgar; Lønmo, Tor Inge Birkenes & Austeng, Andreas
(2022).
PhD project: Adaptive beamforming in underwater detection and estimation problems.
-
(2021).
3D rendering of shipwrecks from synthetic aperture sonar.
Show summary
Synthetic aperture sonar (SAS) bathymetric mapping provides centimeter-scale lateral and vertical resolution of the seafloor. Typically, SAS data has been visualized as 2D images or gridded 2.5D surfaces, but it can also be plotted as 3D point clouds. Even if the imaging system is not fully volumetric, the imaging geometry leaves the possibility of having data points that reside in the same lateral positions in a ground coordinate system. Visualizing these without geometric distortion or loss of data is challenging. In this paper we have investigated the use of full-fledged 3D rendering with artificial lighting and shading techniques using the open-source software Blender in order to convey more of the available information to a human observer. The motivation for this study is to produce better 3D visualization of shipwrecks from a chemical munitions dump site in the Skagerrak sea south of Norway. We provide an overview of which data products are available from state-of-the-art SAS processing, and explore existing visualization methods. We discuss the use of 2.5D surfaces, 3D surfaces and point clouds for 3D rendering, as well as various shading and rendering techniques. These include lighting, surface shading, volumetric shading, emission shading and camera techniques. Our goal is to display SAS bathymetry in a way that is both intuitive and appealing to a general audience, and can convey more supplemental information to the observer than other visualization techniques. Finally, we show image and video examples of rendering large shipwreck scenes using data collected by a HISAS1032 SAS carried by a HUGIN autonomous underwater vehicle.
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La Manna, Nicolas; Lyons, Anthony P. & Hansen, Roy Edgar
(2021).
The effect of internal waves on synthetic aperture sonar resolution.
-
(2020).
Backscatter Features for Estimating Synthetic Aperture Sonar Bathymetry.
-
(2020).
Backscatter Features for Estimating Synthetic Aperture Sonar Bathymetry.
OCEANS.
ISSN 0197-7385.
Show summary
Synthetic aperture sonar (SAS) bathymetric mapping has matured in recent years and is adopted by industry,
government and academia for mapping and exploration of large
areas in more detail than previously feasible. As with other types
of bathymetric mapping, averaging is often a critical processing
step in order to gain sufficient signal quality to ensure the reliability of the bathymetric product, i.e. the depth map. SAS stands out
from many of the other mapping technologies by the availability
of very high resolution, centimeter-scale backscatter images. In
this paper, we investigate the use of backscatter features to
enhance the resolution and accuracy of the bathymetric product.
The aim is to allow averaging over larger spatial extent inside
of the interferometric processing, while preserving sharp edges
and object boundaries, as well as improving the similarity of the
statistical properties for the averaged cells. We suggest a method
for achieving this by using image segmentation on backscatter
data, and demonstrate the method on simulated and real data
sets. We achieved better edge preservation on protruding objects,
more accurate bathymetry estimates, higher object signal to noise
ratio and sharper SAS images after geometric corrections due to
the improved bathymetry estimate.
-
(2020).
Estimating the spatial coherence of narrowband underwater acoustic signals.
-
(2020).
Estimating the spatial coherence of narrowband underwater acoustic signals.
OCEANS.
ISSN 0197-7385.
-
(2020).
Estimating the spatial coherence of narrowband underwater acoustic signals.
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Pate, David J.; Cook, Daniel A.; Lyons, Anthony P. & Hansen, Roy Edgar
(2019).
Characterization of internal waves in SAS imagery via ray tracing.
-
(2019).
Fusion Digital Terrain Models for Synthetic Aperture Sonar Interferometry.
-
(2019).
Comparison of synthetic aperture sonar images and optical images of UXOs from the Skagerrak chemical munitions dumpsite.
-
(2019).
Through-the-sensor sharpness estimation for synthetic aperture sonar images.
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Blachet, Antoine; Plets, Ruth; Sacchetti, Fabio; Austeng, Andreas; Hunter, Alan, J & Hansen, Roy Edgar
(2019).
MBES DATA SIMULATION: ASSESSMENT BY DIRECT
COMPARISON WITH A HIGH-RESOLUTION MULTI-SETTINGS
WRECK SURVEY.
-
-
(2019).
Mapping the ocean floor in extreme resolution using interferometric synthetic aperture sonar.
-
(2018).
High Resolution Imaging And Mapping Of The Seabed Using Synthetic Aperture Sonar.
-
(2018).
Exploring the Ocean Floor with Synthetic Aperture Sonar.
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Pate, David J.; Cook, Daniel A.; Lyons, Anthony P. & Hansen, Roy Edgar
(2018).
Characterization of internal waves in synthetic aperture sonar imagery via ray tracing.
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Lyons, Anthony P.; Olson, Derek R. & Hansen, Roy Edgar
(2018).
Quantifying the effect of random roughness on synthetic aperture sonar image statistics.
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Blachet, Antoine; Austeng, Andreas; Prieur, Fabrice Jean Gabriel & Hansen, Roy Edgar
(2018).
Multibeam echosounder survey simulation.
Show summary
- An efficient tool for simulating new sonar design and surveys.
- Models sonar system for a given choice of array geometry and pulse shape.
- Simulates the Doppler effect induced by the motion of each transducer.
- Example of configurations and motion induced artifact are presented .
-
(2018).
Investigating layover effects in cross-correlation based interferometry for synthetic aperture sonar.
-
(2018).
Challenges in Coregistration of Repeated Passes in Synthetic Aperture Sonar.
-
Myers, Vincent; Sæbø, Torstein Olsmo & Hansen, Roy Edgar
(2018).
Comparison of co-registration techniques for synthetic aperture sonar images from repeated passes.
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Sternlicht, Daniel D.; Hayes, Michael P. & Hansen, Roy Edgar
(2018).
Historical development of seabed mapping synthetic aperture sonar.
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Hansen, Roy Edgar; Lyons, Anthony P.; Cook, Daniel A. & Sæbø, Torstein Olsmo
(2018).
Quantifying the negative impact of breaking internal waves on interferometric synthetic aperture sonar.
-
(2017).
Synthetic Aperture Sonar Interferometry Mapping of the Seabed.
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Austeng, Andreas; Rodriguez-Molares, Alfonso & Hansen, Roy Edgar
(2017).
Performance of coherence based adaptive sonar beamformers.
-
(2017).
Depth estimation of water column objects using interferometric synthetic aperture sonar.
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Myers, Vincent; Quidu, I.; Sæbø, Torstein Olsmo; Hansen, Roy Edgar & Zerr, Benoit
(2017).
Computing navigation corrections for co-registration of repeat-pass synthetic aperture sonar images.
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Lyons, Anthony P.; Hansen, Roy Edgar; Prater, James; Connors, Warren A.; Rice, Glen & Pailhas, Yan
(2017).
Internal wave effects on seafloor imagery and bathymetry estimates.
-
(2017).
Synthetic aperture sonar interferometry for detailed seabed mapping: Performance considerations.
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Blachet, Antoine; Lønmo, Tor Inge Birkenes; Austeng, Andreas; Prieur, Fabrice Jean Gabriel; Hunter, Alan, J & Hansen, Roy Edgar
(2017).
SONAR DATA SIMULATION WITH APPLICATION TO MULTIBEAM
ECHO SOUNDERS.
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Lønmo, Tor Inge Birkenes; Austeng, Andreas & Hansen, Roy Edgar
(2017).
Phase Detections with Low Complexity Adaptive Beamforming on Swath Sonars.
-
(2017).
Local probability-based phase unwrapping for synthetic aperture sonar interferometry.
-
(2017).
Mapping unexploded ordnance (UXO) using interferometric synthetic aperture sonar.
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Geilhufe, Marc; Voss, Hauke; Hansen, Roy Edgar; Midtgaard, Øivind; Synnes, Stig Asle Vaksvik & Sæbø, Torstein Olsmo
(2017).
Towards automated HF sidescan sonar performance estimation.
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Lyons, Anthony P.; Olson, Derek R. & Hansen, Roy Edgar
(2016).
Quantifying the effect of random seafloor roughness on high-frequency synthetic aperture sonar image statistics.
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Lønmo, Tor Inge Birkenes; Austeng, Andreas; Hansen, Roy Edgar & Tichy, Frank
(2020).
Adaptive Beamforming and Autocalibration for Swath Sonars.
Universitetet i Oslo.
ISSN 1501-7710.
Full text in Research Archive
Show summary
Accurate knowledge of the seabed is of vital importance for many human endeavors. Applications range from safe navigation to climate change models. Swath sonars are a key tool for efficient and high-resolution mapping of the seabed. This thesis aims to improve the quality of swath sonars by improving the beamformer, which is a key part of current signal processing.
We explore two methods: Adaptive beamforming and autocalibration. Adaptive beamforming improves the beamforming process by adapting the beamforming to the received signal. We investigate how the adaptive Capon and Low Complexity Adaptive (LCA) beamformers can improve swath sonar beamforming on both simulated and field data, and their effect on the water column image and bathymetry. The Capon beamformer is well-tested and can give high performance, but has a high computational load and may have robustness issues. LCA is a recently developed and related adaptive beamformer which may be more robust and faster, with similar performance in many ways.
We find that both beamformers improve resolution, edge definition and sidelobe level in the water column, and give more accurate amplitude detections. This leads to better defined features, better separation of features from the background, and sometimes detection of features not visible with the conventional delay and sum (DAS) beamformer. Capon has better resolution, somewhat better edge definition, and somewhat higher sidelobe level than LCA. We also find that an adaptive beamformer may improve interference rejection for phase detection, but generally reduces accuracy in the current configuration. This seems to be a side effect of the improved edge definition, and the effect can be reduced by reconfiguring the beamformers.
Autocalibration estimates calibration errors without external reference sources. The errors, which particularly limit the sidelobe level, may then be compensated for. We model the errors by a complex factor per element and estimate them using data available during normal surveys. The method is based on the Generalized Interferometric Array Response. On simulated data, we are able to lower the sidelobe level below 50 dB. On field data, the sidelobe level is generally reduced, but the effect is much smaller. However, some sidelobes are unchanged and new sidelobes occasionally appear. We suggest that the reduced performance in the field is due to an insufficient calibration model.
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Ødegård, Øyvind; Sørensen, Asgeir Johan; Johnsen, Geir; Ludvigsen, Martin; Hansen, Roy Edgar & Maarleveld, Thijs
(2018).
Towards Autonomous Operations and Systems in Marine Archaeology.
NTNU.
ISSN 978-82-326-3196-4.
2018(IMT-12).