Note
This page is a reference documentation. It only explains the function signature, and not how to use it. Please refer to the user guide for the big picture.
nilearn.signal.butterworth#
- nilearn.signal.butterworth(signals, sampling_rate, low_pass=None, high_pass=None, order=5, copy=False)[source]#
Apply a low-pass, high-pass or band-pass Butterworth filter.
Apply a filter to remove signal below the low frequency and above the high frequency.
- Parameters
- signals
numpy.ndarray
(1D sequence or n_samples x n_sources) Signals to be filtered. A signal is assumed to be a column of signals.
- sampling_rate
float
Number of samples per time unit (sample frequency).
- low_pass
float
or None, optional Low cutoff frequency in Hertz. If specified, signals above this frequency will be filtered out. If None, no low-pass filtering will be performed. Default=None.
- high_pass
float
, optional High cutoff frequency in Hertz. If specified, signals below this frequency will be filtered out. Default=None.
- order
int
, optional Order of the Butterworth filter. When filtering signals, the filter has a decay to avoid ringing. Increasing the order sharpens this decay. Be aware that very high orders can lead to numerical instability. Default=5.
- copy
bool
, optional If False, signals is modified inplace, and memory consumption is lower than for
copy=True
, though computation time is higher.
- signals
- Returns
- filtered_signals
numpy.ndarray
Signals filtered according to the given parameters.
- filtered_signals