imu_filter.py 文件源码

def imu_filter_lowpass(x, order = 4, sRate = 148.148148148148, highcut = 20.0):
    """ Forward-backward band-pass filtering (IIR butterworth filter) """
    nyq = 0.5 * sRate
    high = highcut/nyq
    b, a = butter(N =order, Wn = high, btype = 'low')
    return filtfilt(b=b, a=a, x=x, axis=0, method = 'pad', padtype = 'odd',
                    padlen = np.minimum(3*len(a)*len(b), x.shape[0]-1))