bandpass.py 文件源码

def filter(self, s, axis=0):
        """Filter new data.
        """
        if self.bandType == 'allpass':
            return s
        if self.bandType == 'allstop':
            return np.zeros_like(s)

        """ Should be very close to filtfilt, padding? XXX - idfah
        if self.zeroPhase:
            rev = [slice(None),]*s.ndim
            rev[axis] = slice(None,None,-1)

            #ziScaled = self.scaleZi(s[rev], axis)

            y, newZi = spsig.lfilter(self.numCoef, self.denomCoef, s[rev], axis=axis, zi=newZi)
            y = y[rev]
        """

        # if zeroPhase and signal is shorter than padlen (default in filtfilt function)
        if self.zeroPhase and \
            (3*max(len(self.numCoef), len(self.denomCoef))) < s.shape[axis]:

            # need astype below since filtfilt calls lfilter_zi, which does not preserve dtype XXX - idfah
            return spsig.filtfilt(self.numCoef, self.denomCoef,
                        s, axis=axis, padtype='even').astype(self.dtype, copy=False)

        else:
            ziScaled = self.scaleZi(s, axis)

            # even padding to help reduce edge effects
            nPad = 3*max(len(self.numCoef), len(self.denomCoef))
            sPad = np.apply_along_axis(np.pad, axis, s, pad_width=nPad, mode='reflect') # edge for constant padding
            slc = [slice(nPad,-nPad) if i == axis else slice(None) for i in range(s.ndim)]

            y, newZi = spsig.lfilter(self.numCoef, self.denomCoef, sPad, axis=axis, zi=ziScaled)

            return y[slc]