filtering.py 文件源码

def spike_filtfilt(data, lowcut=None, highcut=None, *, fs=None, verbose=False):
    """Filter data to the spike band (default 600--6000 Hz).

    Parameters
    ----------
    data : AnalogSignalArray, ndarray, or list
    lowcut : float, optional (default 600 Hz)
        Lower cut-off frequency
    highcut : float, optional (default 6000 Hz)
        Upper cut-off frequency
    fs : float, optional if AnalogSignalArray is passed
        Sampling frequency (Hz)

    Returns
    -------
    filtered : same type as data
    """

    if isinstance(data, (np.ndarray, list)):
        if fs is None:
            raise ValueError("sampling frequency must be specified!")
    elif isinstance(data, AnalogSignalArray):
        if fs is None:
            fs = data.fs

    if lowcut is None:
        lowcut = 600
    if highcut is None:
        highcut = 6000

    [b, a] = butter(2, lowcut/(fs/2), btype='highpass')
    [bhigh, ahigh] = butter(1, highcut/(fs/2))

    if isinstance(data, (np.ndarray, list)):
        # Filter raw data
        spikedata = filtfilt(b, a,filtfilt(bhigh, ahigh, data))
        return spikedata
    elif isinstance(data, AnalogSignalArray):
        spikedata = filtfilt(b, a, filtfilt(bhigh, ahigh, data.ydata))

        # Return a copy of the AnalogSignalArray with the filtered data
        out = copy.copy(data)
        out._ydata = spikedata
        return out