tools.py 文件源码

def get_freqs (signals, nbins=0):
    """ extracts relative fft frequencies and bins them in n bins
    :param signals: 1D or 2D signals
    :param nbins:  number of bins used as output (default: maximum possible)
    """
    if signals.ndim == 1: signals = np.expand_dims(signals,0)
    sfreq = use_sfreq
    if nbins == 0: nbins = int(sfreq/2)

    nsamp = float(signals.shape[1])
    assert nsamp/2 >= nbins, 'more bins than fft results' 

    feats = np.zeros((int(signals.shape[0]),nbins),dtype='float32')
    w = (fft(signals,axis=1)).real
    for i in np.arange(nbins):
        feats[:,i] =  np.sum(np.abs(w[:,np.arange(i*nsamp/sfreq,(i+1)*nsamp/sfreq, dtype=int)]),axis=1)
    sum_abs_pow = np.sum(feats,axis=1)
    feats = (feats.T / sum_abs_pow).T
    return feats