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Modified Beamformers for Coherent Source Region Suppression

S.S. Dalal, K. Sekihara, S.S. Nagarajan
2006 IEEE Transactions on Biomedical Engineering  
A vector beamformer is then constructed by rejecting the contribution of sources in the suppression region while allowing for source reconstruction at other specified regions.  ...  or that the correlation structure between sources is known.  ...  ACKNOWLEDGMENT The authors would like to thank A. M. Findlay and S. M. Honma for their assistance in acquiring MEG data, as well as J. M. Zumer and K. E. Hild for helpful discussions.  ... 
doi:10.1109/tbme.2006.873752 pmid:16830939 pmcid:PMC3066091 fatcat:cm3ms3jiavhhjdt3kozm2fjfzm

Developing a Multi-channel Beamformer by Enhancing Spatially Constrained ICA for Recovery of Correlated EEG Sources

N Samadzadehaghdam, B MakkiAbadi, E Eqlimi, F Mohagheghian, H Khajehpoor, M H Harirchian
2018 Journal of Biomedical Physics and Engineering  
Therefore, it could be used as a robust beamformer in recovering correlated brain sources.  ...  Recently, beamformers have gained a lot of consideration in the EEG inverse problem.Objective: Beamformers lack acceptable performance in the case of correlated brain sources.  ...  Acknowledgment This study is part of a PhD thesis supported by Tehran University of Medical sciences (grant No: 95-01-30-31612).  ... 
doi:10.31661/jbpe.v0i0.801 pmid:33937127 pmcid:PMC8064133 fatcat:yj24uimxsjcxpphfmpivr7gv54

Testing covariance models for MEG source reconstruction of hippocampal activity [article]

George C O'Neill, Daniel N Barry, Tim M Tierney, Stephanie Mellor, Eleanor A Maguire, Gareth R Barnes
2021 biorxiv/medrxiv   pre-print
Beamforming is one of the most commonly used source reconstruction methods for magneto- and electroencephalography (M/EEG).  ...  We found that incorporating a correlated hippocampal source model significantly improved model evidence.  ...  Eleanor Maguire is supported by a Wellcome Principal Research Fellowship (210567/Z/18/Z).  ... 
doi:10.1101/2021.04.29.441929 fatcat:xqoooddkezezljjhu3o4sydmbi

Imaging in radio interferometry by iterative subset scanning using a modified AMP algorithm

Giovanni Cherubini, Paul Hurley, Matthieu Simeoni, Sanaz Kazemi
2016 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)  
Example of sky image reconstruction Radio interferometry Conclusions and next steps  ...  matched beamforming towards the center of the field of view at all stations; randomized beamforming is used to increase diversity. • Beamformed signals are correlated to get so called visibilities, which  ...  sources located on each subset. • At the end of a scan, identify those points in the region of interest that have the highest probability of "hosting" a source. • Modify the subsets of points by 1) including  ... 
doi:10.1109/icassp.2016.7472293 dblp:conf/icassp/CherubiniHSK16 fatcat:7blk65l24zg6fgimfwlsv57tvy

Comparison of beamforming methods to reconstruct extended, partially-correlated sources

Blaine M. Harker, Kent L. Gee, Tracianne B. Neilsen, Alan T. Wall
2017 Journal of the Acoustical Society of America  
This paper compares the abilities of three cross beamforming methods to reproduce source and field characteristics for an extended, partially correlated source that mimics supersonic jet noise radiation  ...  The successful application of the three methods demonstrate the utility of crossbeamforming in formulating equivalent source models for accurate field prediction of complex sources, including jet noise  ...  The Hybrid Method The hybrid method (HM) provides improved capabilities over conventional beamforming by using a modified regularization technique to constrain the beamforming results in such a way as  ... 
doi:10.1121/1.4989105 fatcat:y6gn6ffcyrdcjg47it4f7263xu

Time-Delayed Mutual Information of the Phase as a Measure of Functional Connectivity

Andreas Wilmer, Marc de Lussanet, Markus Lappe, Satoru Hayasaka
2012 PLoS ONE  
Furthermore, the compatibility to inverse methods for a source reconstruction in MEG such as beamforming techniques is controlled by dedicated dipole simulations.  ...  An embedding with a parametric time-delay allows a reconstruction of arbitrary nonstationary connective structuresso-called connectivity patterns -in a wide class of systems such as coupled oscillatory  ...  Steinberg for providing the data of their MEG study. We would also like to express our gratitude to the anonymous reviewers for their valuable comments to improve this manuscript.  ... 
doi:10.1371/journal.pone.0044633 pmid:23028571 pmcid:PMC3445535 fatcat:digkqjelrvhcronilbc6zm6upy

On the Potential of a New Generation of Magnetometers for MEG: A Beamformer Simulation Study

Elena Boto, Richard Bowtell, Peter Krüger, T. Mark Fromhold, Peter G. Morris, Sofie S. Meyer, Gareth R. Barnes, Matthew J. Brookes, Blake Johnson
2016 PLoS ONE  
Here, using simulations, we quantify the advantages of hypothetical OPM systems in terms of sensitivity, reconstruction accuracy and spatial resolution.  ...  However, we also show that such improvements depend critically on accurate forward models; indeed, the reconstruction accuracy of our simulated OPM system only outperformed that of a simulated superconducting  ...  Our results also show a clear improvement in the accuracy of beamformer source reconstruction; average correlation between simulated and beamformer-reconstructed sources increased significantly for our  ... 
doi:10.1371/journal.pone.0157655 pmid:27564416 pmcid:PMC5001648 fatcat:tfys7ccs2bbhvbk4nouy32airu

Examining the Effects of One- and Three-Dimensional Spatial Filtering Analyses in Magnetoencephalography

Sam Johnson, Garreth Prendergast, Mark Hymers, Gary Green, Yong He
2011 PLoS ONE  
predominantly radial sources in the case of a multiple-spheres forward model.  ...  Although routinely referred to as a single technique, beamforming in fact encompasses several different methods, both with regard to defining the spatial filters used to reconstruct source-space time series  ...  Figure 1 suggests that in a non-radial direction, a three 1-d spatial filter implementation of a vectorised beamformer is able to reconstruct a known source with a high correlation and an accurate gain  ... 
doi:10.1371/journal.pone.0022251 pmid:21857916 pmcid:PMC3152290 fatcat:3umgwnqdzred5bgz37f6igdwh4

Source reconstruction of broadband EEG/MEG data using the frequency-adaptive broadband (FAB) beamformer [article]

Matthias Treder, Guido Nolte
2018 bioRxiv   pre-print
A beamformer enhances the signal from a voxel of interest by minimising interference from all other locations represented in the sensor covariance matrix.  ...  The FAB beamformer significantly outperforms both methods in terms of the quality of the reconstructed time series.  ...  The 400 Pearson correlation between the known true time series and the reconstructed source 401 was used as reconstruction quality measure. 402 In simulation 1, using narrowband noise sources and a single  ... 
doi:10.1101/502690 fatcat:ivn2psg6gfhuherl2fdizpccbu

A new approach to neuroimaging with magnetoencephalography

Arjan Hillebrand, Krish D. Singh, Ian E. Holliday, Paul L. Furlong, Gareth R. Barnes
2005 Human Brain Mapping  
We discuss the application of beamforming techniques to the field of magnetoencephalography (MEG).  ...  We argue that beamformers have given us an insight into the dynamics of oscillatory changes across the cortex not explored previously with traditional analysis techniques that rely on averaged evoked responses  ...  This is followed by a comparison of MEG beamformers to source reconstruction algorithms that are typically used to analyse average evoked responses.  ... 
doi:10.1002/hbm.20102 pmid:15846771 fatcat:xej6cd5manc6va2tkujqi4s64y

Localization accuracy of a common beamformer for the comparison of two conditions

Gustavo Lucena Gómez, Philippe Peigneux, Vincent Wens, Mathieu Bourguignon
2021 NeuroImage  
The linearly constrained minimum variance beamformer is frequently used to reconstruct sources underpinning neuromagnetic recordings.  ...  When reconstructions must be compared across conditions, it is considered good practice to use a single, "common" beamformer estimated from all the data at once.  ...  of the European Commission (grant 743562).  ... 
doi:10.1016/j.neuroimage.2021.117793 pmid:33497769 fatcat:lmodf6k55jhgzdoz4jx3rhx74i

Performance of an MEG adaptive-beamformer technique in the presence of correlated neural activities: effects on signal intensity and time-course estimates

K. Sekihara, S.S. Nagarajan, D. Poeppel, A. Marantz
2002 IEEE Transactions on Biomedical Engineering  
The influence of temporarily correlated source activities on neuromagnetic reconstruction by adaptive beamformer techniques was investigated.  ...  A method of retrieving the original time courses using estimated correlation coefficients was developed.  ...  These discrete sources are modeled using the equivalent current dipoles [17] .  ... 
doi:10.1109/tbme.2002.805485 pmid:12549735 fatcat:es26qinzb5cr5ee3idrpjpcopu

Modified covariance beamformer for solving MEG inverse problem in the environment with correlated sources [article]

Aleksandra Kuznetsova, Julia Nurislamova, Alexei Ossadtchi
2019 bioRxiv   pre-print
experimental paradigms result into a great deal of correlation in the activity of cortical sources.  ...  Over recent years non-globally optimized solutions based on the use of adaptive beamformers (BF) gained popularity.When operating in the environment with a small number of uncorrelated sources the BFs  ...  Simulated data were generated using a dense cortical grid of 20000 sources, and source reconstruction procedure used a four times sparser cortical model with 5000 sources.  ... 
doi:10.1101/668814 fatcat:tyfncwjttfchzenoua7hmy7ys4

Reconstruction methods for acoustic particle detection in the deep sea using clusters of hydrophones

2009 Astroparticle physics  
The reconstruction of the position of an acoustic point source in the sea is performed by using small-volume clusters of hydrophones (about 1 cubic meter) for direction reconstruction by a beamforming  ...  The directional information from a number of such clusters allows for position reconstruction.  ...  All plots demonstrate that using local clusters for direction reconstruction and using that information to reconstruct a source is a good approach for point source location.7 Summary and OutlookThis article  ... 
doi:10.1016/j.astropartphys.2008.11.003 fatcat:3t74ervrurbgdecohotwngk4au

Compressive Sound Speed Profile Inversion Using Beamforming Results

Youngmin Choo, Woojae Seong
2018 Remote Sensing  
The SSP is estimated using CS with beamforming of ray arrivals in the SWellEx-96 experimental environment, and the performance is evaluated using the correlation coefficient and mean squared error (MSE  ...  In this work, the SSP is inverted using compressive sensing (CS) combined with beamforming to indicate the direction of arrivals (DOAs).  ...  Here, instead of using beamforming, DOAs are calculated with eigenrays from the ray model, which connect the source to the receiver.  ... 
doi:10.3390/rs10050704 fatcat:mnbfbjes7jbdzckbowzss3dho4
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