Python numpy.hamming() 使用实例

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Example 1

def phormants(x, Fs):
    N = len(x)
    w = numpy.hamming(N)

    # Apply window and high pass filter.
    x1 = x * w   
    x1 = lfilter([1], [1., 0.63], x1)
    
    # Get LPC.    
    ncoeff = 2 + Fs / 1000
    A, e, k = lpc(x1, ncoeff)    
    #A, e, k = lpc(x1, 8)

    # Get roots.
    rts = numpy.roots(A)
    rts = [r for r in rts if numpy.imag(r) >= 0]

    # Get angles.
    angz = numpy.arctan2(numpy.imag(rts), numpy.real(rts))

    # Get frequencies.    
    frqs = sorted(angz * (Fs / (2 * math.pi)))

    return frqs 

Example 2

def hamming(M):
    """Returns the Hamming window.

    The Hamming window is defined as

    .. math::
        w(n) = 0.54 - 0.46\\cos\\left(\\frac{2\\pi{n}}{M-1}\\right)
        \\qquad 0 \\leq n \\leq M-1

    Args:
        M (:class:`~int`):
            Number of points in the output window. If zero or less, an empty
            array is returned.

    Returns:
        ~cupy.ndarray: Output ndarray.

    .. seealso:: :func:`numpy.hamming`
    """
    if M < 1:
        return from_data.array([])
    if M == 1:
        return basic.ones(1, float)
    n = ranges.arange(0, M)
    return 0.54 - 0.46 * trigonometric.cos(2.0 * numpy.pi * n / (M - 1)) 

Example 3

def cochleagram_extractor(xx, sr, win_len, shift_len, channel_number, win_type):
    fcoefs, f = make_erb_filters(sr, channel_number, 50)
    fcoefs = np.flipud(fcoefs)
    xf = erb_frilter_bank(xx, fcoefs)

    if win_type == 'hanning':
        window = np.hanning(channel_number)
    elif win_type == 'hamming':
        window = np.hamming(channel_number)
    elif win_type == 'triangle':
        window = (1 - (np.abs(channel_number - 1 - 2 * np.arange(1, channel_number + 1, 1)) / (channel_number + 1)))
    else:
        window = np.ones(channel_number)
    window = window.reshape((channel_number, 1))

    xe = np.power(xf, 2.0)
    frames = 1 + ((np.size(xe, 1)-win_len) // shift_len)
    cochleagram = np.zeros((channel_number, frames))
    for i in range(frames):
        one_frame = np.multiply(xe[:, i*shift_len:i*shift_len+win_len], np.repeat(window, win_len, 1))
        cochleagram[:, i] = np.sqrt(np.mean(one_frame, 1))

    cochleagram = np.where(cochleagram == 0.0, np.finfo(float).eps, cochleagram)
    return cochleagram 

Example 4

def log_power_spectrum_extractor(x, win_len, shift_len, win_type, is_log=False):
    samples = x.shape[0]
    frames = (samples - win_len) // shift_len
    stft = np.zeros((win_len, frames), dtype=np.complex64)
    spect = np.zeros((win_len // 2 + 1, frames), dtype=np.float64)

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'rectangle':
        window = np.ones(win_len)

    for i in range(frames):
        one_frame = x[i*shift_len: i*shift_len+win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft[:, i] = np.fft.fft(windowed_frame, win_len)
        if is_log:
            spect[:, i] = np.log(np.power(np.abs(stft[0: win_len//2+1, i]), 2.))
        else:
            spect[:, i] = np.power(np.abs(stft[0: win_len//2+1, i]), 2.)

    return spect 

Example 5

def stft_extractor(x, win_len, shift_len, win_type):
    samples = x.shape[0]
    frames = (samples - win_len) // shift_len
    stft = np.zeros((win_len, frames), dtype=np.complex64)
    spect = np.zeros((win_len // 2 + 1, frames), dtype=np.complex64)

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'rectangle':
        window = np.ones(win_len)

    for i in range(frames):
        one_frame = x[i*shift_len: i*shift_len+win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft[:, i] = np.fft.fft(windowed_frame, win_len)
        spect[:, i] = stft[: win_len//2+1, i]

    return spect 

Example 6

def rasta_plp_extractor(x, sr, plp_order=0, do_rasta=True):
    spec = log_power_spectrum_extractor(x, int(sr*0.02), int(sr*0.01), 'hamming', False)
    bark_filters = int(np.ceil(freq2bark(sr//2)))
    wts = get_fft_bark_mat(sr, int(sr*0.02), bark_filters)
    bark_spec = np.matmul(wts, spec)
    if do_rasta:
        bark_spec = np.where(bark_spec == 0.0, np.finfo(float).eps, bark_spec)
        log_bark_spec = np.log(bark_spec)
        rasta_log_bark_spec = rasta_filt(log_bark_spec)
        bark_spec = np.exp(rasta_log_bark_spec)
    post_spec = postaud(bark_spec, sr/2.)
    if plp_order > 0:
        lpcas = do_lpc(post_spec, plp_order)
    else:
        lpcas = post_spec
    return lpcas 

Example 7

def spectrum_extractor(x, win_len, shift_len, win_type, is_log):
    samples = x.shape[0]
    frames = (samples - win_len) // shift_len
    stft = np.zeros((win_len, frames), dtype=np.complex64)
    spectrum = np.zeros((win_len // 2 + 1, frames), dtype=np.float64)

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'triangle':
        window = (1 - (np.abs(win_len - 1 - 2 * np.arange(1, win_len + 1, 1)) / (win_len + 1)))
    else:
        window = np.ones(win_len)
    for i in range(frames):
        one_frame = x[i*shift_len: i*shift_len+win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft[:, i] = np.fft.fft(windowed_frame, win_len)
        if is_log:
            spectrum[:, i] = np.log(np.abs(stft[0: win_len//2+1, i]))
        else:
            spectrum[:, i] = np.abs(stft[0: win_len // 2 + 1:, i])

    return spectrum 

Example 8

def smooth(s,lengthscale,parallel=True):
    """smoothes s vertically"""
    if len(s.shape) == 1:
        s=s[...,None]
    nChans = s.shape[1]
    lengthscale=2*round(float(lengthscale)/2)
    W = np.hamming(min(lengthscale,s.shape[0]))
    W/= np.sum(W)
    if s.shape[1]>1:
        if parallel:
            njobs=JOBLIB_NCORES
        else:
            njobs=1

        slidingMean = (Parallel(n_jobs=njobs,backend=JOBLIB_BACKEND,temp_folder=JOBLIB_TEMPFOLDER)
                        (delayed(smoothLine)(s[:,chan],W) for chan in range(nChans)))
        return np.array(slidingMean).T
    else:
        return smoothLine(s[:,0],W)[...,None] 

Example 9

def __init__(self, sampling_rate=16000, frame_width=0.032, frame_shift=0.01, num_mel_filters=40, window_func="hanning",
		using_delta=True, using_delta_delta=True):
		assert window_func in ["hanning", "hamming"]
		self.sampling_rate = sampling_rate
		self.frame_width = frame_width
		self.sampling_rate = sampling_rate
		self.frame_width = frame_width
		self.frame_shift = frame_shift
		self.num_fft = int(sampling_rate * frame_width)
		self.num_mel_filters = num_mel_filters

		if window_func == "hanning":
			self.window_func = lambda x:np.hanning(x)
		elif winfunc == "hamming":
			self.window_func = lambda x:np.hamming(x)

		self.using_delta = using_delta
		self.using_delta_delta = using_delta_delta

		self.fbank = fft.get_filterbanks(nfft=self.num_fft, nfilt=num_mel_filters, samplerate=sampling_rate) 

Example 10

def Specgram(X, W, H):
    """A function to compute the spectrogram of a signal
    :parm X: N x 1 Audio Signal
    :param W: Window Size
    :param H HopSize
    :returns: S, an N x NBins spectrogram array
    """
    Q = W/H
    if Q - np.floor(Q) > 0:
        print('Warning: Window size is not integer multiple of hop size\n')
    win = np.hamming(W)
    NWin = int(np.floor((len(X) - W)/float(H)) + 1)
    S = np.zeros((NWin, W))
    for i in range(NWin):
        x = X[i*H:i*H+W]
        S[i, :] = np.abs(np.fft.fft(win*x))
    #Second half of the spectrum is redundant for real signals
    if W % 2 == 0:
        #Even Case
        S = S[:, 0:W/2]
    else:
        #Odd Case
        S = S[:, 0:(W-1)/2+1]
    return S 

Example 11

def _mfcc_and_labels(audio, labels):
  """ Convert to MFCC features and corresponding (interpolated) labels.

  Returns:
    A tuple, `(mfcc_features, mfcc_labels)`. A 1-D float array and a 1-D int
      array, both with the same shape.
  """
  mfcc_sample_rate = 100.0
  winfunc = lambda x: np.hamming(x)
  mfcc_features = python_speech_features.mfcc(audio, samplerate=timit.SAMPLE_RATE, winlen=0.025,
                                              winstep=1.0/mfcc_sample_rate, lowfreq=85.0,
                                              highfreq=timit.SAMPLE_RATE/2, winfunc=winfunc)
  t_audio = np.linspace(0.0, audio.shape[0] * 1.0 / timit.SAMPLE_RATE, audio.size, endpoint=False)
  t_mfcc = np.linspace(0.0, mfcc_features.shape[0] * 1.0 / mfcc_sample_rate, mfcc_features.shape[0], endpoint=False)
  interp_func = scipy.interpolate.interp1d(t_audio, labels, kind='nearest')
  mfcc_labels = interp_func(t_mfcc)
  return mfcc_features, mfcc_labels 

Example 12

def make_spectrogram(self, seg_length, window_func=np.hamming):
        """Computes the spectrogram of the wave.

        seg_length: number of samples in each segment
        window_func: function used to compute the window

        returns: Spectrogram
        """
        n = len(self.ys)
        window = window_func(seg_length)

        start, end, step = 0, seg_length, seg_length / 2
        spec_map = {}

        while end < n:
            ys = self.ys[start:end] * window
            hs = np.fft.rfft(ys)

            t = (start + end) / 2.0 / self.framerate
            spec_map[t] = Spectrum(hs, self.framerate)

            start += step
            end += step

        return Spectrogram(spec_map, seg_length, window_func) 

Example 13

def discontinuity(num_periods=30, hamming=False):
    """Plots the spectrum of a sinusoid with/without windowing.

    num_periods: how many periods to compute
    hamming: boolean whether to apply Hamming window
    """
    signal = thinkdsp.SinSignal(freq=440)
    duration = signal.period * num_periods
    wave = signal.make_wave(duration)

    if hamming:
        wave.hamming()

    print(len(wave.ys), wave.ys[0], wave.ys[-1])
    spectrum = wave.make_spectrum()
    spectrum.plot(high=60) 

Example 14

def three_spectrums():    
    """Makes a plot showing three spectrums for a sinusoid.
    """
    thinkplot.preplot(rows=1, cols=3)

    pyplot.subplots_adjust(wspace=0.3, hspace=0.4, 
                           right=0.95, left=0.1,
                           top=0.95, bottom=0.05)

    xticks = range(0, 900, 200)

    thinkplot.subplot(1)
    thinkplot.config(xticks=xticks)
    discontinuity(num_periods=30, hamming=False)

    thinkplot.subplot(2)
    thinkplot.config(xticks=xticks)
    discontinuity(num_periods=30.25, hamming=False)

    thinkplot.subplot(3)
    thinkplot.config(xticks=xticks)
    discontinuity(num_periods=30.25, hamming=True)

    thinkplot.save(root='windowing1') 

Example 15

def _smooth(params, win, type="HAMMING"):
    

    win = int(win+0.5)
    if win >= len(params)-1:
        win = len(params)-1
    if win % 2 == 0:
        win+=1

    s = np.r_[params[win-1:0:-1],params,params[-1:-win:-1]]

    
    if type=="HAMMING":
        w = np.hamming(win)
        third = int(win/5)
        #w[:third] = 0
    else:
        w = np.ones(win)
        
        
    y = np.convolve(w/w.sum(),s,mode='valid')
    return y[(win/2):-(win/2)] 

Example 16

def __init__(self, master, input_connect=None):
        Component.__init__(self, master, input_connect)
        self.master = master
        self.progeny = []
        self.dur_since_last_birth = 0
        self.curr_period = default.CURR_GEN_PERIOD
        self.curr_dur = default.CURR_GRAIN_LEN
        self.curr_lag = default.CURR_GEN_LAG
        self.curr_period_jitter = default.CURR_GEN_PERIOD_JITTER
        self.curr_dur_jitter = default.CURR_GRAIN_LEN_JITTER
        self.curr_lag_jitter = default.CURR_LAG_JITTER
        
        def generate_envelope(length):
            """ Generates hamming windowing function. """
            envelope = list(np.hamming(length))
            return(envelope)
        self.envelope_generator = generate_envelope 

Example 17

def iFFT(Y, output_length=None, window=False):
    """ Inverse real-valued Fourier Transform

    Parameters
    ----------
    Y : array_like
       Frequency domain data [Nsignals x Nbins]
    output_length : int, optional
       Lenght of returned time-domain signal (Default: 2 x len(Y) + 1)
    win : boolean, optional
       Weights the resulting time-domain signal with a Hann

    Returns
    -------
    y : array_like
       Reconstructed time-domain signal
    """
    Y = _np.atleast_2d(Y)
    y = _np.fft.irfft(Y, n=output_length)

    if window:
        if window not in {'hann', 'hamming', 'blackman', 'kaiser'}:
            raise ValueError('Selected window must be one of hann, hamming, blackman or kaiser')
        no_of_signals, no_of_samples = y.shape

        if window == 'hann':
            window_array = _np.hanning(no_of_samples)
        elif window == 'hamming':
            window_array = _np.hamming(no_of_samples)
        elif window == 'blackman':
            window_array = _np.blackman(no_of_samples)
        elif window == 'kaiser':
            window_array = _np.kaiser(no_of_samples, 3)
        y = window_array * y
    return y 

Example 18

def synthesis_speech(noisy_speech, ideal_mask, win_type, win_len, shift_len, syn_method='A&R'):
    samples = noisy_speech.shape[0]
    frames = (samples - win_len) // shift_len

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'rectangle':
        window = np.ones(win_len)
    to_ifft = np.zeros(win_len, dtype=np.complex64)
    clean_speech = np.zeros((frames-1)*shift_len+win_len, dtype=np.float32)
    window_sum = np.zeros((frames-1)*shift_len+win_len, dtype=np.float32)
    for i in range(frames):
        one_frame = noisy_speech[i * shift_len: i * shift_len + win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft = np.fft.fft(windowed_frame, win_len)
        masked_abs = np.abs(stft[:win_len//2+1]) * ideal_mask[:, i]
        to_ifft[:win_len//2+1] = masked_abs * np.exp(1j * np.angle(stft[:win_len//2+1]))
        to_ifft[win_len//2+1:] = np.conj(to_ifft[win_len//2-1:0:-1])
        speech_seg = np.real(np.fft.ifft(to_ifft, win_len))

        if syn_method == 'A&R' or syn_method == 'ALLEN & RABINER':
            clean_speech[i*shift_len:i*shift_len+win_len] += speech_seg
            window_sum[i*shift_len:i*shift_len+win_len] += window

        elif syn_method == 'G&L' or syn_method == 'GRIFFIN & LIM':
            speech_seg = np.multiply(speech_seg, window)
            clean_speech[i * shift_len:i * shift_len + win_len] += speech_seg
            window_sum[i * shift_len:i * shift_len + win_len] += np.power(window, 2.)
        # if i > 0:
        #     clean_speech[i*shift_len: (i-1)*shift_len+win_len] *= 0.5
    window_sum = np.where(window_sum < 1e-2, 1e-2, window_sum)
    return clean_speech / window_sum 

Example 19

def synthesis_speech(ns, mk, win_type, win_len, shift_len, syn_method='A&R'):
    samples = ns.shape[0]
    frames = (samples - win_len) // shift_len

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'rectangle':
        window = np.ones(win_len)
    to_ifft = np.zeros(win_len, dtype=np.complex64)
    clean_speech = np.zeros((frames-1)*shift_len+win_len, dtype=np.float32)
    window_sum = np.zeros((frames-1)*shift_len+win_len, dtype=np.float32)
    for i in range(frames):
        one_frame = ns[i * shift_len: i * shift_len + win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft = np.fft.fft(windowed_frame, win_len)
        masked_abs = np.abs(stft[:win_len//2+1]) * mk[:, i]
        to_ifft[:win_len//2+1] = masked_abs * np.exp(1j * np.angle(stft[:win_len//2+1]))
        to_ifft[win_len//2+1:] = np.conj(to_ifft[win_len//2-1:0:-1])
        speech_seg = np.real(np.fft.ifft(to_ifft, 320))

        if syn_method == 'A&R' or syn_method == 'ALLEN & RABINER':
            clean_speech[i*shift_len:i*shift_len+win_len] += speech_seg
            window_sum[i*shift_len:i*shift_len+win_len] += window

        elif syn_method == 'G&L' or syn_method == 'GRIFFIN & LIM':
            speech_seg = np.multiply(speech_seg, window)
            clean_speech[i * shift_len:i * shift_len + win_len] += speech_seg
            window_sum[i * shift_len:i * shift_len + win_len] += np.power(window, 2.)
        # if i > 0:
        #     clean_speech[i*shift_len: (i-1)*shift_len+win_len] *= 0.5
    window_sum = np.where(window_sum < 1e-2, 1e-2, window_sum)
    return clean_speech / window_sum 

Example 20

def fir1(n, wn):
    # Variables definition :
    nbands = len(wn) + 1
    ff = np.array((0, wn[0], wn[0], wn[1], wn[1], 1))

    f0 = np.mean(ff[2:4])
    l = n + 1

    mags = np.array(range(nbands)) % 2
    aa = np.ravel(np.matlib.repmat(mags, 2, 1), order='F')

    # Get filter coefficients :
    h = firls(l - 1, ff, aa)

    # Apply a window to coefficients :
    wind = np.hamming(l)
    b = np.matrix(h.T * wind)
    c = np.matrix(np.exp(-1j * 2 * np.pi * (f0 / 2) * np.array(range(l))))
    b = b / abs(c * b.T)

    return np.squeeze(np.array(b)), 1 

Example 21

def fir1(N, Wn):
    # Variables definition :
    nbands = len(Wn) + 1
    ff = np.array((0, Wn[0], Wn[0], Wn[1], Wn[1], 1))

    f0 = np.mean(ff[2:4])
    L = N + 1

    mags = np.array(range(nbands)) % 2
    aa = np.ravel(repmat(mags, 2, 1), order='F')

    # Get filter coefficients :
    h = firls(L - 1, ff, aa)

    # Apply a window to coefficients :
    Wind = np.hamming(L)
    b = np.matrix(h.T * Wind)
    c = np.matrix(np.exp(-1j * 2 * np.pi * (f0 / 2) * np.array(range(L))))
    b = b / abs(c * b.T)

    return np.ndarray.squeeze(np.array(b)), 1


####################################################################
# - Filt the signal :
#################################################################### 

Example 22

def __init__(self, sample_rate, frame_length):
        ''' 
        Initialize MFCC Calculator.
        @param sample_rate: audio sample rate
        @param input_size: length of magnitude spectrum (half of FFT size assumed)            
        '''
        self.sample_rate = sample_rate
        self.nyquist = sample_rate / 2.0
        self.min_hz = 0
        self.max_hz = self.nyquist
        self.input_size = frame_length / 2
        self.num_bands = 40
        self.window = np.hamming(frame_length)
        self.filter_matrix = None
        return 

Example 23

def __init__(self, samplerate, framelen):
        '''
        Initialize perceptual loudness using samplerate and framelength
        '''
        self.framelen = framelen
        self.window = np.hamming(framelen)
        self.filter = np.zeros(framelen / 2)
        for i in xrange(framelen / 2):
            self.filter[i] = self.__weightA(float(i * samplerate) / framelen)
        return 

Example 24

def __init__(self, path, time_wnd = 25, time_off = 10):
        wave_src = wave.open(path, "rb")
        para_src = wave_src.getparams()
        self.rate = int(para_src[2])
        self.cur_size = 0
        self.tot_size = int(para_src[3])
        # default 400 160
        self.wnd_size = int(self.rate * 0.001 * time_wnd)
        self.wnd_rate = int(self.rate * 0.001 * time_off)
        self.ham = np.hamming(self.wnd_size+1)
	self.ham = np.sqrt(self.ham[0:self.wnd_size])
	self.ham = self.ham / np.sqrt(np.sum(np.square(self.ham[range(0,self.wnd_size, self.wnd_rate)])))
        self.data = np.fromstring(wave_src.readframes(wave_src.getnframes()), dtype=np.int16)
        self.upper_bound = np.max(np.abs(self.data)) 

Example 25

def __init__(self, path, time_wnd = 25, time_off = 10):
        wave_src = wave.open(path, "rb")
        para_src = wave_src.getparams()
        self.rate = int(para_src[2])
        self.cur_size = 0
        self.tot_size = int(para_src[3])
        # default 400 160
        self.wnd_size = int(self.rate * 0.001 * time_wnd)
        self.wnd_rate = int(self.rate * 0.001 * time_off)
        self.ham = np.hamming(self.wnd_size+1)
	self.ham = np.sqrt(self.ham[0:self.wnd_size])
	self.ham = self.ham / np.sqrt(np.sum(np.square(self.ham[range(0,self.wnd_size, self.wnd_rate)])))
        self.data = np.fromstring(wave_src.readframes(wave_src.getnframes()), dtype=np.int16)
        self.upper_bound = np.max(np.abs(self.data)) 

Example 26

def getFFT(data,rate):
    """Given some data and rate, returns FFTfreq and FFT (half)."""
    data=data*np.hamming(len(data))
    fft=np.fft.fft(data)
    fft=np.abs(fft)
    #fft=10*np.log10(fft)
    freq=np.fft.fftfreq(len(fft),1.0/rate)
    return freq[:int(len(freq)/2)],fft[:int(len(fft)/2)] 

Example 27

def smooth(x,window_len=11,window='hanning'):

    if x.ndim != 1:
        raise ValueError, "smooth only accepts 1 dimension arrays."

    if x.size < window_len:
    	return x
        # raise ValueError, "Input vector needs to be bigger than window size."


    if window_len<3:
        return x


    if not window in ['flat', 'hanning', 'hamming', 'bartlett', 'blackman']:
        raise ValueError, "Window is one of 'flat', 'hanning', 'hamming', 'bartlett', 'blackman'"


    s=numpy.r_[x[window_len-1:0:-1],x,x[-1:-window_len:-1]]
    if window == 'flat': #moving average
        w=numpy.ones(window_len,'d')
    else:
        w=eval('numpy.'+window+'(window_len)')

    y=numpy.convolve(w/w.sum(),s,mode='valid')
    y = y[(window_len/2-1) : -(window_len/2)-1]
    return y 

Example 28

def smooth(values, window):
    oavg = numpy.mean(abs(values))
    #weights = numpy.repeat(1.0, window)/window
    weights = numpy.hamming(window)
    sma = numpy.convolve(values, weights, 'valid')
    sma = sma[0:len(values)]
    navg = numpy.mean(abs(sma))
    sma = sma * (oavg / navg)
    return sma 

Example 29

def smooth(values, window):
  #weights = numpy.repeat(1.0, window)/window
  weights = numpy.hamming(window)
  sma = numpy.convolve(values, weights, 'valid')
  sma = sma[0:len(values)]
  return sma

# https://github.com/tcort/va2epr-tnc/blob/master/firmware/aprs.c
# Thomas Cort <[email protected]>
# update a CRC with one new byte.
# initial crc should be 0xffff. 

Example 30

def hamming(self):
        """Apply a Hamming window to the wave.
        """
        self.ys *= np.hamming(len(self.ys)) 

Example 31

def window_plot():
    """Makes a plot showing a sinusoid, hamming window, and their product.
    """
    signal = thinkdsp.SinSignal(freq=440)
    duration = signal.period * 10.25
    wave1 = signal.make_wave(duration)
    wave2 = signal.make_wave(duration)

    ys = numpy.hamming(len(wave1.ys))
    window = thinkdsp.Wave(ys, wave1.framerate)

    wave2.hamming()

    thinkplot.preplot(rows=3, cols=1)

    pyplot.subplots_adjust(wspace=0.3, hspace=0.3, 
                           right=0.95, left=0.1,
                           top=0.95, bottom=0.05)

    thinkplot.subplot(1)
    wave1.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07])

    thinkplot.subplot(2)
    window.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07])

    thinkplot.subplot(3)
    wave2.plot()
    thinkplot.config(axis=[0, duration, -1.07, 1.07],
                     xlabel='time (s)')

    thinkplot.save(root='windowing2') 

Example 32

def standard_specgram(signal):
	"Return specgram matrix, made using the audio-layer config"
	return np.array(specgram(signal, NFFT=audioframe_len, noverlap=audioframe_len-audioframe_stride, window=np.hamming(audioframe_len))[0][specbinlow:specbinlow+specbinnum,:], dtype=float32) 

Example 33

def make_wave(self):
        """Inverts the spectrogram and returns a Wave.

        returns: Wave
        """
        res = []
        for t, spectrum in sorted(self.spec_map.items()):
            wave = spectrum.make_wave()
            n = len(wave)
            
            window = 1 / np.hamming(n)
            wave.window(window)

            i = wave.find_index(t)
            start = i - n // 2
            end = start + n
            res.append((start, end, wave))

        starts, ends, waves = zip(*res)
        low = min(starts)
        high = max(ends)

        ys = np.zeros(high-low, np.float)
        for start, end, wave in res:
            ys[start:end] = wave.ys

        # ts = np.arange(len(ys)) / self.framerate
        return Wave(ys, framerate=wave.framerate) 

Example 34

def hamming(self):
        """Apply a Hamming window to the wave.
        """
        self.ys *= np.hamming(len(self.ys)) 

Example 35

def make_spectrogram(self, seg_length, win_flag=True):
        """Computes the spectrogram of the wave.

        seg_length: number of samples in each segment
        win_flag: boolean, whether to apply hamming window to each segment

        returns: Spectrogram
        """
        if win_flag:
            window = np.hamming(seg_length)
        i, j = 0, seg_length
        step = seg_length / 2

        # map from time to Spectrum
        spec_map = {}

        while j < len(self.ys):
            segment = self.slice(i, j)
            if win_flag:
                segment.window(window)

            # the nominal time for this segment is the midpoint
            t = (segment.start + segment.end) / 2
            spec_map[t] = segment.make_spectrum()

            i += step
            j += step

        return Spectrogram(spec_map, seg_length) 

Example 36

def __init__(self, block_length=1024, fft_length=None, step=None,
                 wfunc=np.hamming, fs=1., donorm=True):

        self.block_length = block_length
        self.fft_length = fft_length
        self.step = step
        self.wfunc = wfunc
        self.fs = fs
        self.donorm = donorm
        self.psd = [] 

Example 37

def __init__(self, block_length=1024, fft_length=None, step=None,
                 wfunc=np.hamming, fs=1.):
        super(Coherence,
              self).__init__(block_length=block_length, fft_length=fft_length,
                             step=step, wfunc=wfunc, fs=fs)

        self.coherence = None 

Example 38

def __init__(self, block_length=1024, fft_length=None, step=None,
                 wfunc=np.hamming, fs=1.):

        super(Bicoherence,
              self).__init__(block_length=block_length, fft_length=fft_length,
                             step=step, wfunc=wfunc, fs=fs) 

Example 39

def local_hamming(vec):
    return(hamming(len(vec))) 

Example 40

def FFT(data,rate):
    """given some data points and a rate, return [freq,power]"""
    data=data*np.hamming(len(data))
    fft=np.fft.fft(data)
    fft=10*np.log10(np.abs(fft))
    freq=np.fft.fftfreq(len(fft),1/rate)
    return freq[:int(len(freq)/2)],fft[:int(len(fft)/2)] 

Example 41

def filterSimMat(simMat, filtLength, filtType, scaleFilterMethod='max1'):
	if filtType == 'hamming':
		filt = np.hamming(filtLength)
	elif filtType == 'flat':
		filt = np.ones(filtLength)
	else:
		raise RuntimeError("Unknown/unsupported filter type {}".format(filtType))
	if scaleFilterMethod == 'max1':
		filt /= np.max(filt)
	elif scaleFilterMethod == 'sum1':
		filt /= np.sum(filt)
	# print filt
	# filt = np.tile(filt, (simMat.shape[0], 1))
	# print filt.shape
	return filters.convolve1d(simMat, weights=filt, axis=1, mode='constant') 

Example 42

def preprocessFeatureMat(X, Lfilt):
	"""
	Binarizes and blurs the feature matrix

	Parameters
	----------
	X : 2D array
		The original feature matrix (presumably output by buildFeatureMat())
	Lfilt : int
		The width of the hamming filter used to blur the feature matrix.

	Returns
	-------
	X : 2D array
		The modified feature matrix without blur
	Xblur : 2D array
		The modified feature matrix with blur
	"""
	Xblur = _filterRows(X, Lfilt)

	# ensure that the maximum value in Xblur is 1; we do this by dividing
	# by the largets value within Lfilt / 2, rather than just clamping, so
	# that there's a smooth dropoff as you move away from dense groups of
	# 1s in X; otherwise it basically ends up max-pooled
	maxima = filters.maximum_filter1d(Xblur, Lfilt // 2, axis=1, mode='constant')
	Xblur[maxima > 0] /= maxima[maxima > 0]

	# have columns be adjacent in memory
	return np.asfortranarray(X), np.asfortranarray(Xblur) 

Example 43

def _filterRows(X, filtLength):
	filt = np.hamming(filtLength)
	return filters.convolve1d(X, weights=filt, axis=1, mode='constant') 

Example 44

def filterRows(X, filtLength, filtType='hamming', scaleFilterMethod='max1'):
	if filtType == 'hamming':
		filt = np.hamming(filtLength)
	elif filtType == 'flat':
		filt = np.ones(filtLength)
	else:
		raise RuntimeError("Unknown/unsupported filter type {}".format(filtType))
	if scaleFilterMethod == 'max1':
		filt /= np.max(filt)
	elif scaleFilterMethod == 'sum1':
		filt /= np.sum(filt)

	return filters.convolve1d(X, weights=filt, axis=1, mode='constant') 

Example 45

def notSoRandomWalk(shape, std=1, trendFilterLength=32, lpfLength=16):
	"""bandpass filter a random walk so that the low-frequency trend /
	drift is eliminated and the high-frequency noise is attenuated"""
	walk = randwalk(shape, std=std)
	filt = np.hamming(trendFilterLength)
	filt /= np.sum(filt)
	whichAxis = len(walk.shape) > 1 # 0 iff 1d, else 1
	# subtract baseline drift, roughly
	trend = filters.convolve1d(walk, weights=filt, axis=whichAxis, mode='reflect')
	walk -= trend
	# subtract noisey spikes
	walk = filters.convolve1d(walk, weights=np.hamming(lpfLength), axis=whichAxis, mode='reflect')
	return walk 

Example 46

def _filterRows(X, filtLength):
	filt = np.hamming(filtLength)
	return filters.convolve1d(X, weights=filt, axis=1, mode='constant') 

Example 47

def compute_feature_vector(eegdata, Fs):
    """
    Extract the features from the EEG
    
    Arguments:
    eegdata: array of dimension [number of samples, number of channels]
    Fs: sampling frequency of eegdata
    
    Outputs:
    feature_vector: np.array of shape [number of feature points; number of different features]

    """
    #Delete last column (Status)
    eegdata = np.delete(eegdata, -1 , 1)    
        
    # 1. Compute the PSD
    winSampleLength, nbCh = eegdata.shape
    
    # Apply Hamming window
    w = np.hamming(winSampleLength)
    dataWinCentered = eegdata - np.mean(eegdata, axis=0) # Remove offset
    dataWinCenteredHam = (dataWinCentered.T*w).T

    NFFT = nextpow2(winSampleLength)
    Y = np.fft.fft(dataWinCenteredHam, n=NFFT, axis=0)/winSampleLength
    PSD = 2*np.abs(Y[0:NFFT/2,:])
    f = Fs/2*np.linspace(0,1,NFFT/2)     
            
    # SPECTRAL FEATURES
    # Average of band powers
    # Delta <4
    ind_delta, = np.where(f<4)
    meanDelta = np.mean(PSD[ind_delta,:],axis=0)
    # Theta 4-8
    ind_theta, = np.where((f>=4) & (f<=8))
    meanTheta = np.mean(PSD[ind_theta,:],axis=0)
    # Alpha 8-12
    ind_alpha, = np.where((f>=8) & (f<=12)) 
    meanAlpha = np.mean(PSD[ind_alpha,:],axis=0)
    # Beta 12-30
    ind_beta, = np.where((f>=12) & (f<30))
    meanBeta = np.mean(PSD[ind_beta,:],axis=0)
    
    feature_vector = np.concatenate((meanDelta, meanTheta, meanAlpha, meanBeta),
                                    axis=0)
    
    feature_vector = np.log10(feature_vector)   
       
    return feature_vector 

Example 48

def fft_continuous(data, n=None, psd=False, log='log', fs=None,
                   window='hamming'):
    """Apply the Fast Fourier Transform on continuous data.

    Apply the Fast Fourier Transform algorithm on continuous data to get
    the spectrum.
    Steps:
        1- Demeaning
        2- Apply hamming window
        3- Compute FFT
        4- Grab lower half

    Args:
        data (numpy.ndarray): shape (`n_samples`, `n_channels`). Data for
            which to get the FFT

    Keyword Args:
        n (int): length of the FFT. If longer than `n_samples`, zero-padding
            is used; if smaller, then the signal is cropped. If None, use
            the same number as the number of samples
        psd (bool): if True, return the Power Spectral Density
        log (string): can be 'log' (log10(x)), 'log+1' (log10(x+1)) or None
        fs (float): Sampling rate of `data`.
        window (string): if 'no_window' do not use a window before
            applying the FFT. Otherwise, use as the window function.
            Currently only supports 'hamming'.

    Returns:
        (numpy.ndarray) Fourier Transform of the original signal
        (numpy.ndarray): array of frequency bins
    """
    if data.ndim == 1:
        data = data.reshape((-1, 1))
    [n_samples, n_channels] = data.shape

    data = data - data.mean(axis=0)
    if window.lower() == 'hamming':
        H = np.hamming(n_samples).reshape((-1, 1))
    elif window.lower() == 'no_window':
        H = np.ones(n_samples).reshape((-1, 1))
    else:
        raise ValueError('window value {} is not supported'.format(window))
    L = np.min([n_samples, n]) if n else n_samples
    Y = np.fft.fft(data * H, n, axis=0) / L
    freq_bins = (fs * np.arange(0, Y.shape[0] / 2 + 1) / Y.shape[0]) \
        if fs is not None else None

    out = Y[0:int(Y.shape[0] / 2) + 1, :]
    out[:, 0] = 2 * out[:, 0]

    if psd:
        out = np.abs(out) ** 2
    if log == 'log':
        out = np.log10(out)
    elif log == 'log+1':
        out = np.log10(out + 1)

    return out, freq_bins 

Example 49

def mfcc_extractor(xx, sr, win_len, shift_len, mel_channel, dct_channel, win_type, include_delta):

    my_melbank = get_fft_mel_mat(win_len, sr, mel_channel)

    pre_emphasis_weight = 0.9375

    # x = xx * (1-pre_emphasis_weight)
    x = np.append(xx[0], xx[1:] - pre_emphasis_weight * xx[:-1])
    dctcoef = np.zeros((dct_channel, mel_channel), dtype=np.float32)
    for i in range(dct_channel):
        n = np.linspace(0, mel_channel-1, mel_channel)
        dctcoef[i, :] = np.cos((2 * n + 1) * i * np.pi / (2 * mel_channel))

    w = 1 + 6 * np.sin(np.pi * np.linspace(0, dct_channel-1, dct_channel) / (dct_channel-1))
    w /= w.max()
    w = np.reshape(w, newshape=(dct_channel, 1))

    samples = x.shape[0]
    frames = (samples - win_len) // shift_len
    stft = np.zeros((win_len, frames), dtype=np.complex64)
    spectrum = np.zeros((win_len // 2 + 1, frames), dtype=np.float32)

    mfcc = np.zeros((dct_channel, frames), dtype=np.float32)

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'triangle':
        window = (1-(np.abs(win_len - 1 - 2*np.arange(1, win_len+1, 1))/(win_len+1)))
    else:
        window = np.ones(win_len)

    for i in range(frames):
        one_frame = x[i * shift_len: i * shift_len + win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft[:, i] = np.fft.fft(windowed_frame, win_len)
        spectrum[:, i] = np.power(np.abs(stft[0:win_len // 2 + 1, i]), 2)

    c1 = np.matmul(my_melbank, spectrum)
    c1 = np.where(c1 == 0.0, np.finfo(float).eps, c1)
    mfcc[:dct_channel, :] = np.multiply(np.matmul(dctcoef, np.log(c1)), np.repeat(w, frames, 1))

    if include_delta:
        dtm = np.zeros((dct_channel, frames), dtype=np.float32)
        ddtm = np.zeros((dct_channel, frames), dtype=np.float32)
        for i in range(2, frames-2):
            dtm[:, i] = 2 * mfcc[:, i+2] + mfcc[:, i+1] - mfcc[:, i-1] - 2 * mfcc[:, i-2]
        dtm /= 3.0
        for i in range(2, frames-2):
            ddtm[:, i] = 2 * dtm[:, i+2] + dtm[:, i+1] - dtm[:, i-1] - 2 * dtm[:, i-2]
        ddtm /= 3.0
        mfcc = np.row_stack((mfcc[:, 4:frames-4], dtm[:, 4:frames-4], ddtm[:, 4:frames-4]))

    return mfcc, spectrum 

Example 50

def mfcc_extractor(xx, sr, win_len, shift_len, mel_channel, dct_channel, win_type, include_delta):

    my_melbank = get_fft_mel_mat(win_len, sr, mel_channel)

    pre_emphasis_weight = 0.9375

    # x = xx * (1-pre_emphasis_weight)
    x = np.append(xx[0], xx[1:] - pre_emphasis_weight * xx[:-1])
    dctcoef = np.zeros((dct_channel, mel_channel), dtype=np.float32)
    for i in range(dct_channel):
        n = np.linspace(0, mel_channel-1, mel_channel)
        dctcoef[i, :] = np.cos((2 * n + 1) * i * np.pi / (2 * mel_channel))

    w = 1 + 6 * np.sin(np.pi * np.linspace(0, dct_channel-1, dct_channel) / (dct_channel-1))
    w /= w.max()
    w = np.reshape(w, newshape=(dct_channel, 1))

    samples = x.shape[0]
    frames = (samples - win_len) // shift_len
    stft = np.zeros((win_len, frames), dtype=np.complex64)
    spectrum = np.zeros((win_len // 2 + 1, frames), dtype=np.float32)

    mfcc = np.zeros((dct_channel, frames), dtype=np.float32)

    if win_type == 'hanning':
        window = np.hanning(win_len)
    elif win_type == 'hamming':
        window = np.hamming(win_len)
    elif win_type == 'triangle':
        window = (1-(np.abs(win_len - 1 - 2*np.arange(1, win_len+1, 1))/(win_len+1)))
    else:
        window = np.ones(win_len)

    for i in range(frames):
        one_frame = x[i * shift_len: i * shift_len + win_len]
        windowed_frame = np.multiply(one_frame, window)
        stft[:, i] = np.fft.fft(windowed_frame, win_len)
        spectrum[:, i] = np.power(np.abs(stft[0:win_len // 2 + 1, i]), 2)

    c1 = np.matmul(my_melbank, spectrum)
    c1 = np.where(c1 == 0.0, np.finfo(float).eps, c1)
    mfcc[:dct_channel, :] = np.multiply(np.matmul(dctcoef, np.log(c1)), np.repeat(w, frames, 1))

    if include_delta:
        dtm = np.zeros((dct_channel, frames), dtype=np.float32)
        ddtm = np.zeros((dct_channel, frames), dtype=np.float32)
        for i in range(2, frames-2):
            dtm[:, i] = 2 * mfcc[:, i+2] + mfcc[:, i+1] - mfcc[:, i-1] - 2 * mfcc[:, i-2]
        dtm /= 3.0
        for i in range(2, frames-2):
            ddtm[:, i] = 2 * dtm[:, i+2] + dtm[:, i+1] - dtm[:, i-1] - 2 * dtm[:, i-2]
        ddtm /= 3.0
        mfcc = np.row_stack((mfcc[:, 4:frames-4], dtm[:, 4:frames-4], ddtm[:, 4:frames-4]))

    return mfcc, spectrum 
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