filtering EEG data - notch filter

About the GUI application to design signal processing pipelines
Post Reply
rkamile
Posts: 7
Joined: Mon Oct 26, 2020 2:22 pm

filtering EEG data - notch filter

Post by rkamile »

Hello,

I wanted to ask something regarding data filtering. I use Unicorn EEG device from g.tec and I am sending the data through LSL to OpenVibe. I send the data out from OpenVibe as OSC message to the network and receive it with another program in order to program sound.Image

I am trying to do some filtering in between and I managed to add bandpass filter (0.5-30Hz) which works nicely,

Image

but I also want to add 60Hz Notch filter. I don't know how to do this. Shall I take the same temporal filter? I tried this but probably it doesn't make sense:

Image

Could you please help me with this? I want my data to be a little bit more stable because now I feel like there is still too much noise and I can't trust it. All insights of how it could be improved are highly welcomed!

Thank you very much.
Best,
Kamile

Thibaut
Posts: 227
Joined: Wed Oct 31, 2018 9:14 am

Re: filtering EEG data - notch filter

Post by Thibaut »

Hi,
If you have a band pass of 0.5-30, you have only frequency between this 2 values so filter of 60Hz is useless.^^
The noise can come from your setup (maybe electromagnetic, move, not enough gel....)
Thibaut

rkamile
Posts: 7
Joined: Mon Oct 26, 2020 2:22 pm

Re: filtering EEG data - notch filter

Post by rkamile »

Thank you Thibaut for your answer. However, notch filter is meant to remove the interference of the mains or electrical power supply that leak through everywhere... So I figured that in my country it is 50Hz, 220V. I understand what you say but the makers of the EEG device recommends to use both notch and bandpass filter.

Thibaut
Posts: 227
Joined: Wed Oct 31, 2018 9:14 am

Re: filtering EEG data - notch filter

Post by Thibaut »

HI,
I think it depends your algorithm, you can use a band stop filter if your wan't but irt's useless.
Thibaut

Post Reply