braindecode.preprocessing.RemoveDCOffset

class braindecode.preprocessing.RemoveDCOffset(*, can_change_duration=False, record_orig_chanlocs=False, force_dtype=None)

Remove the DC offset from the EEG data by subtracting the per-channel median.

This preprocessor mainly exists because some EEG data (depending on the electrical characteristics of the hardware) can have such a large DC offset that highpass filters do not necessarily fully remove it, unless some care is taken with filter settings (noted in EEGLAB documentation [Delorme2004]).

The operation performed is:

\[X'_{c,t} = X_{c,t} - \text{median}_t(X_{c,t})\]

where \(c\) indexes the channel and \(t\) indexes time.

References

[Delorme2004]

Delorme, A. and Makeig, S., 2004. EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis. Journal of Neuroscience Methods, 134(1), pp.9-21.

Methods

apply_eeg(eeg, raw)

Apply the preprocessor to an EEGLAB EEG structure.

Return type:

dict[str, Any]