butter_lowpass_filter#

pypillometry.signal.butter_lowpass_filter(data, cutoff, fs, order=5)[source]#

Lowpass-filter signal using a Butterworth-filter.

The filter is applied forward and backward (scipy.signal.filtfilt()), so the result has zero phase shift. data must not contain NaN values.

Parameters:

  • data (np.ndarray) – data to lowpass-filter

  • cutoff (float) – lowpass-filter cutoff in Hz

  • fs (float) – sampling rate in Hz

  • order (int) – filter order

Returns:

y (np.ndarray) – filtered data