Signal Processing Stack Exchange
Signal Processing Stack Exchange

Questions tagged [eeg]

The recording of voltages along the scalp for the purpose of monitoring brain wave activity and localizing sources of ionic currents

126 questions
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Is ICA appropriate for separating mixed signals when all source signals are NOT detectable at all sensors?

A generic implementation of ICA for the separation of a mixture of $N$ signals into their $M$ constituent components requires that the signals be assumed to be a linear instantaneous mixture of the sources. Every description of ICA that I have come…
Laura
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What is averaging and how can it be done?

I'm studying about the analysis of (mainly) fMRI and EEG data. Multiple times it's mentioned that to reduce noise, you can use averaging, but nothing more detailed than that. There never is literally stated that you can use this or that technique to…
Mien
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How can I distinguish between two similar EEG signals?

I have two EEG signals that are very similar. The difference is only in amplitudes. However, they are coming from two different cognitive processes. What are some methods, beside FFT, for distinguishing between two very similar signals in terms of…
BrainStorm
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How to correctly compute the EEG Frequency Bands with Python?

so I am trying to compute the EEG(25 channels, 512 sampling rate, 248832/channel) bands (alpha, beta, gamma, etc.) with Python. I managed to do so by: firstly filtering the signal with a butterworth filter that looks like this: def…
user3640476
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How does averaging increase the Signal to Noise ratio?

When attempting to spot activities on an EEG waveform given a stimuli, it is recommended that several trials be taken and their average is done to increase the SNR. Intuitively, since noise is not stationary or localized, averaging different trials…
Fraïssé
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Howto calculate SNR for EEG data?

This question is about SNR in the context of EEG. (a related question about SNR) I am interested in calculating The SNR of an ERP. My motivation is: To calculate the "signal-to-noise ratio" and from this to extract the information (how?) on how…
Dov
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Correct method for drawing waveforms

I need to draw waveforms for biometric data like ECG and EEG signals. When I have more samples than pixels at the X-axis, I need to draw a vertical line between the MIN and MAX sample-value for that period. Now I was wondering, suppose the signal is…
Maestro
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Assumptions for Hurst exponent calculation

Are there any general assumptions for the calculation of the Hurst exponent? Does the signal need to be stationary, for example? Does it depend on the method? What about the length of the time series, is longer better? I am interested in using…
sviter
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Which order to perform downsampling and filtering?

I have EEG data recorded with 128Hz sampling rate. As my goal is to reduce the amount of data (and maybe noise), I want to downsample the data to 64Hz (I am only interested in range 0.5 - 30Hz). I would perform downsampling (64Hz) and use a…
ppasler
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What Is Meant by Clustering of ICA (Independent Component Analysis) Components?

I'm following the EEGLAB tutorial about STUDY creation and manipulation of the datasets, and came across the concept of clustering of ICA components. I'm not too familiar with processing of ICA components other than its physical meaning which is…
Sanjan Das
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Can an EEG be re-sampled to fix a poor voltage resolution?

I’ve made quite a bad mistake in ca. 14 EEG recordings – I recorded at 10uV resolution @ 5000 Hz instead of 0.1 uV @ 500 Hz. I’m conducting an ERP experiment, and the signals of interest are on the order of ~5 uV. I’m wondering if there is any way…
PKnight
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Cross correlate a 2D array

I have a 2D array of eeg data with shape (64,512) - 64 electrodes, 512 timepoints I want to calculate the maximum cross correlation (irrespective of lag/time shift) between every single electrode, so I end up with a 64x64 array containing max cross…
Simon
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How do you apply Kalman Filter to track a signal?

The example that I've seen on state estimation involves deriving the ABCD matrix of a physical system (i.e. falling object) and tracking that object. I would like to use Kalman Filter for signal denoising applications (specifically EEG signal). How…
Fraïssé
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Large Laplacian Spatial Filter on EEG?

I want to know that why large laplacian spatial filtering is done on EEG signals? I tried a lot but could not find material on LLSF. And what is meant by spatial filter ( in context of Digital Signal Processing)? Why is it called "Large" and…
Muhammad Akmal
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How to compare imaginary coherence values?

High, I am currently writing my Master's thesis on susceptibility for hypnosis. I am comparing EGG signals of lowly and highly susceptible individuals. The imaginary coherence is given by: $$ \text{ImCoh} = \frac{\mathcal{Im}\{E\{S_{xy}\}\}}{…
andyfilip
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