psd_welch(inst, fmin=0, fmax=inf, tmin=None, tmax=None, n_fft=256, n_overlap=0, n_per_seg=None, picks=None, proj=False, n_jobs=1, reject_by_annotation=True, average='mean', verbose=None)¶
Compute the power spectral density (PSD) using Welch’s method.
Calculates periodograms for a sliding window over the time dimension, then averages them together for each channel/epoch.
- instinstance of
The data for PSD calculation.
Min frequency of interest.
Max frequency of interest.
Min time of interest.
Max time of interest.
The length of FFT used, must be
>= n_per_seg(default: 256). The segments will be zero-padded if
n_fft > n_per_seg. If n_per_seg is None, n_fft must be <= number of time points in the data.
The number of points of overlap between segments. Will be adjusted to be <= n_per_seg. The default value is 0.
Length of each Welch segment (windowed with a Hamming window). Defaults to None, which sets n_per_seg equal to n_fft.
Channels to include. Slices and lists of integers will be interpreted as channel indices. In lists, channel type strings (e.g.,
['meg', 'eeg']) will pick channels of those types, channel name strings (e.g.,
['MEG0111', 'MEG2623']will pick the given channels. Can also be the string values “all” to pick all channels, or “data” to pick data channels. None (default) will pick good data channels(excluding reference MEG channels).
Apply SSP projection vectors. If inst is ndarray this is not used.
The number of jobs to run in parallel (default 1). Requires the joblib package.
Whether to omit bad segments from the data while computing the PSD. If True, annotated segments with a description that starts with ‘bad’ are omitted. Has no effect if
instis an Epochs or Evoked object. Defaults to True.
New in version 0.15.0.
How to average the segments. If
mean(default), calculate the arithmetic mean. If
median, calculate the median, corrected for its bias relative to the mean. If
None, returns the unaggregated segments.
New in version 0.19.0.
- instinstance of
ndarray, shape (…, n_freqs) or (…, n_freqs, n_segments)
The power spectral densities. If
average='median'and input is of type Raw or Evoked, then psds will be of shape (n_channels, n_freqs); if input is of type Epochs, then psds will be of shape (n_epochs, n_channels, n_freqs). If
average=None, the returned array will have an additional dimension corresponding to the unaggregated segments.
ndarray, shape (n_freqs,)
New in version 0.12.0.