Noise cancelling of MRS signals combining model-based removal of powerline harmonics and multichannel Wiener filtering
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TLDR
It is shown that noise cancelling can be improved if the multiple origins of noise are taken into account and a method is developed where powerline harmonics are efficiently removed through a modelbased approach.Abstract:
SUMMARY The fidelity of magnetic resonance sounding signals is often severely degraded by noise, primarily electrical interference from powerline harmonics and short electromagnetic discharges. In many circumstances, the noise originates from multiple sources. We show that noise cancelling can be improved if the multiple origins of noise are taken into account. In particular, a method is developed where powerline harmonics are efficiently removed through a modelbased approach. Subsequently, standard multichannel Wiener filtering can be used to provide a further noise reduction. The performance of the method depends on the distribution of noise on the particular site of measurement. Simulations on synthetic signals embedded in real noise recordings show that the combined approach can improve the signal-to-noise ratio with an accompanying improvement in retrieval of model parameters.read more
Citations
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References
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Nuclear magnetic resonance as a geophysical tool for hydrogeologists
TL;DR: In this article, the results of 7 borehole pumping tests and 13 proton Magnetic Resonance Sounding (MRS) measurements are compared to the results obtained through NMR logging.
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Multi-channel surface NMR instrumentation and software for 1D/2D groundwater investigations
TL;DR: In this article, reference coil-based noise cancellation and integrated FID imaging are used to increase the effective signal to noise ratios by an order of magnitude or more, which enables multi-coil surface NMR to produce useful and reliable images when the post-averaged SNR is less than 1.
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Adaptive noise cancelling of multichannel magnetic resonance sounding signals
TL;DR: The results show that within the experimental uncertainty the two methods give identical results, and the design and the efficiency of different stacking methods are compared to time-domain multichannel Wiener filtering.