how should I find noise???

[Ababy]

I think there will be a small amount of noise in measuring EEG, but I don't know how to distinguish noise. Can anyone give me some suggestions or a better way to do this?

[James]

Noise will show as variance of the RAW EEG channels. You want thin crisp lines with spikes only when you blink.

[Ababy]

So, you mean that there is noise in the picture below, but what is the criterion for noise?

raw-brain-waves.png (165.9 KiB) Viewed 2864 times

[James]

As a rule of thumb, I'd say around 50uV of variance is ok, so this looks good. You're always going to have spikes outside that because of blinking.. but most of it is within 50mV.

[Ababy]

You say that a dispersion of around 50uV is acceptable, but in the above figure, the vertical axis scale seems to be more than ±50uV based on 800. To begin with, is it correct that the unit of the vertical axis is uV?

[Ababy]

I have one more question. In the image below, there are marks such as GF (Good Fit), BF (Bad Fit), etc. By what criteria are these marks made?

raw-brain-waves1.png (145.73 KiB) Viewed 2796 times

[James]

This image above is terribly noisy. The markers happen when there is large variance on the RAW EEG, such as above. The scale will change automatically depending on the data range.

[Ababy]

As a rule of thumb, I'd say around 50uV of variance is ok, so this looks good. You're always going to have spikes outside that because of blinking.. but most of it is within 50mV.

You say that a dispersion of around 50uV is acceptable, but in the above figure, the vertical axis scale seems to be more than ±50uV based on 800. To begin with, is it correct that the unit of the vertical axis is uV?

[James]

You want +-50uV from whatever you baseline value it. Different Muse models have different baseline levels. Yours is 800, so you want your RAW EEG to be min 750uV - and max 850uV.
The Graph scale is automatic. If you give it data from -100 to +9999, that'll be the scale it shows. Your data above is from -200 to +2000. It just auto ranges to the min and max data values available.