Compute bridged EEG electrodes using the intrinsic Hjorth algorithm.
First an electrical distance matrix is computed by taking the pairwise
variance. Then, a local maximum near 0 \({\mu}V^2\) and a
a local minimum below 5 \({\mu}V^2\) are found, the presence
of which is indicative of bridging. Finally, electrode distances below
the local minimum are marked as bridged as long as they happen on more
than the epoch_threshold
proportion of epochs.
Based on [1][2][3] and the EEGLAB implementation.
Raw
, Epochs
or Evoked
The data to compute electrode bridging on.
float
The distance in \({\mu}V^2\) cutoff below which to search for a local minimum (lm) indicative of bridging. Defaults to 16 \({\mu}V^2\) to be conservative based on the distributions in [2].
float
The proportion of epochs with electrical distance less than
ed_threshold
in order to consider the channel bridged.
The default is 0.5.
float
The low cutoff frequency to use. Default is 0.5 Hz.
float
The high cutoff frequency to use. Default is 30 Hz.
float
The time in seconds to divide the raw into fixed-length epochs
to check for consistent bridging. Only used if inst
is
mne.io.BaseRaw
. The default is 2 seconds.
None
bw_method
to pass to scipy.stats.gaussian_kde
.
str
| int
| None
Control verbosity of the logging output. If None
, use the default
verbosity level. See the logging documentation and
mne.verbose()
for details. Should only be passed as a keyword
argument.
Notes
New in version 1.1.
References
mne.preprocessing.compute_bridged_electrodes
#Identify EEG Electrodes Bridged by too much Gel