filter.py 文件源码

def detrend(x, order=1, axis=-1):
    """Detrend the array x.

    Parameters
    ----------
    x : n-d array
        Signal to detrend.
    order : int
        Fit order. Currently must be '0' or '1'.
    axis : integer
        Axis of the array to operate on.

    Returns
    -------
    xf : array
        x detrended.

    Examples
    --------
    As in scipy.signal.detrend:
        >>> randgen = np.random.RandomState(9)
        >>> npoints = int(1e3)
        >>> noise = randgen.randn(npoints)
        >>> x = 3 + 2*np.linspace(0, 1, npoints) + noise
        >>> (detrend(x) - noise).max() < 0.01
        True
    """
    from scipy.signal import detrend
    if axis > len(x.shape):
        raise ValueError('x does not have %d axes' % axis)
    if order == 0:
        fit = 'constant'
    elif order == 1:
        fit = 'linear'
    else:
        raise ValueError('order must be 0 or 1')

    y = detrend(x, axis=axis, type=fit)

    return y