Python signal.hann函数代码示例

    def __init__(self, path_to_file, scalar=1, windowed=True):
        self.path = path_to_file
        i = cv2.imread(self.path, cv2.IMREAD_UNCHANGED)
        if i is None:
            raise Exception

        if scalar != 1:
            i = cv2.resize(i, (0, 0), fx=scalar, fy=scalar)
            self.image = i.astype(float) / 255.0
        else:
            self.image = i.astype(float) / 255.0

        self.height, self.width, self.planes = np.shape(self.image)
        if self.planes < 4:
            z = np.ones((self.height, self.width, 4))
            z[:, :, 0:self.planes] = self.image
            self.image = z
            self.height, self.width, self.planes = np.shape(self.image)

        if windowed:
            win = np.vstack(hann(self.height)) * hann(self.width)
            for i in range(self.planes):
                self.image[:, :, i] *= win

        self.image[:, :, 0:3] *= 1. / linalg.norm(self.image[:, :, 0:3])  # normalize

def cross_corr_stack_self(stack, adj_ref = False, verbose = True, pivot_slice = 0):
    '''
    Align a stack to itself. If adj_ref is True, then align each slice to the neighboring slice preceeding it.
    Added: subpixel precision
    '''
    nz, ny, nx = stack.shape
    hy = ny//2
    hx = nx//2
    shift_coord = np.zeros([nz, 2])
    hann_w = signal.hann(nx)
    hann_h = signal.hann(ny)
    hfilter = np.outer(hann_h, hann_w)
    bpf = np.fft.fftshift(bpd(ny,nx))

    container_1 = pyfftw_container(ny, nx)
    container_2 = pyfftw_container(ny, nx)
    container_invx = pyfftw_container(ny, nx, bwd = True)
    if np.isscalar(pivot_slice):
        ref_frame = stack[pivot_slice]
    else:
        ref_frame = pivot_slice

    for ii in range(nz):
        shy, shx  = cross_corr_shift_frame(ref_frame, stack[ii], container_1, container_2, container_invx, filter_freq = 'han', filter_pattern = hfilter )[:2]
        if verbose:
            print("slice ", ii+1, '-->', shy, shx)
        shift_coord[ii] = np.array([-shy, -shx])
        # then we have to shift im 2 by (-shy, -shx)
        if adj_ref:
            # if the stack is aligned in the adjacent mode, them each slice should be updated in place; otherwise we can just return the shift coordinates.
            shifted_frame = interpolation.shift(stack[ii+1],shift = [-shy, -shx])
            ref_frame = shifted_frame
            stack[ii+1] = shifted_frame

    return shift_coord # Hmmmm, this is much nicer.

def basefreq(audiofile):
    """
    This function reads in the audio file and does the hann windowed fft of 
    the right input. It then smooths the output using a gaussian filter and
    then finds the peaks. It returns the peaks in the right audio channel since
    testing showed there was no significant difference in the two.
    """
    #read the data into an ndarray using scikits-audiolab        
    data, rate, enc = al.aiffread(audiofile)
    #split the left and right channel
    datar = data[:,1]
    datal = data[:,0]
    #take the fft of both of the channels with the hann window applied
    #the hann window reduces spectral leakage in the FFT     
    dftr = abs(fft.fft(datar*signal.hann(len(datar))))
    dftl = abs(fft.fft(datal*signal.hann(len(datal))))
    #compute the frequencies in the FFT
    freq = float(rate)/float(len(datar))
    freqs = np.arange(len(dftr)/2+99)*freq
    dftr = dftr[0:np.size(dftr)/2]
    dftl = dftl[0:np.size(dftr)/2]
    #smooth the fft with a gaussian
    c = signal.gaussian(100,20)
    dftr = signal.convolve(dftr,c)
    dftl = signal.convolve(dftl,c)
    #find the significant peaks in each channel
    peaksr = findpeaks(dftr,freqs)
    peaksl = findpeaks(dftl,freqs)
    #plot the output fft for testing
    #plt.plot(freqs,dftr)
    #plt.show()
    #print peaksr
    return peaksr

def _get_window(start, end):
    """Return window which has length as much as parameter start - end."""
    from scipy.signal import hann
    window = 1 - np.r_[hann(4)[:2],
                       np.ones(np.abs(end - start) - 4),
                       hann(4)[-2:]].T
    return window

def window(f,start,stop,type='blackman'):
    """
    runs the data through a hamming window.
    @param f: The data matrix
    @param start: The start index of the hamming window.
    @param stop: The end index of the hamming window.
    """
    h=numpy.zeros(f.shape,dtype=float)

    if len(h.shape)==1:
        if type=='hamming':
            h[start:stop]=signal.hamming(stop-start)
        elif type=='blackman':
            h[start:stop]=signal.blackman(stop-start)
        elif type=='hann':
            h[start:stop]=signal.hann(stop-start)
        elif type=='blackmanharris':
            h[start:stop]=signal.blackmanharris(stop-start)
        elif type=='rectangular' or type=='rect' or type=='boxcar':
            h[start:stop]=signal.boxcar(stop-start)
    else:
        if type=='hamming':
            h[:,start:stop]=signal.hamming(stop-start)
        elif type=='blackman':
            h[:,start:stop]=signal.blackman(stop-start)
        elif type=='hann':
            h[:,start:stop]=signal.hann(stop-start)
        elif type=='blackmanharris':
            h[:,start:stop]=signal.blackmanharris(stop-start)
        elif type=='rectangular' or type=='rect' or type=='boxcar':
            h[:,start:stop]=signal.boxcar(stop-start)
    return numpy.multiply(f,h)

def eliminate_stim_artifact(raw, events, event_id, tmin=-0.005,
                            tmax=0.01, mode='linear'):
    """Eliminates stimulations artifacts from raw data

    The raw object will be modified in place (no copy)

    Parameters
    ----------
    raw : Raw object
        raw data object.
    events : array, shape (n_events, 3)
        The list of events.
    event_id : int
        The id of the events generating the stimulation artifacts.
    tmin : float
        Start time of the interpolation window in seconds.
    tmax : float
        End time of the interpolation window in seconds.
    mode : 'linear' | 'window'
        way to fill the artifacted time interval.
        'linear' does linear interpolation
        'window' applies a (1 - hanning) window.

    Returns
    -------
    raw: Raw object
        raw data object.
    """
    if not raw._preloaded:
        raise RuntimeError('Modifying data of Raw is only supported '
                           'when preloading is used. Use preload=True '
                           '(or string) in the constructor.')
    events_sel = (events[:, 2] == event_id)
    event_start = events[events_sel, 0]
    s_start = int(np.ceil(raw.info['sfreq'] * tmin))
    s_end = int(np.ceil(raw.info['sfreq'] * tmax))

    picks = pick_types(raw.info, meg=True, eeg=True, eog=True, ecg=True,
                       emg=True, ref_meg=True, misc=True, chpi=True,
                       exclude='bads', stim=False, resp=False)

    if mode == 'window':
        window = 1 - np.r_[signal.hann(4)[:2],
                           np.ones(np.abs(s_end - s_start) - 4),
                           signal.hann(4)[-2:]].T

    for k in range(len(event_start)):
        first_samp = int(event_start[k]) - raw.first_samp + s_start
        last_samp = int(event_start[k]) - raw.first_samp + s_end
        data, _ = raw[picks, first_samp:last_samp]
        if mode == 'linear':
            x = np.array([first_samp, last_samp])
            f = interpolate.interp1d(x, data[:, (0, -1)])
            xnew = np.arange(first_samp, last_samp)
            interp_data = f(xnew)
            raw[picks, first_samp:last_samp] = interp_data
        elif mode == 'window':
            raw[picks, first_samp:last_samp] = data * window[np.newaxis, :]
    return raw

 def test_basic(self):
     assert_allclose(signal.hann(6, sym=False),
                     [0, 0.25, 0.75, 1.0, 0.75, 0.25])
     assert_allclose(signal.hann(6, True),
                     [0, 0.3454915028125263, 0.9045084971874737,
                      0.9045084971874737, 0.3454915028125263, 0])
     assert_allclose(signal.hann(7),
                     [0, 0.25, 0.75, 1.0, 0.75, 0.25, 0])

def eliminate_stim_artifact(raw, events, event_id, tmin=-0.005, tmax=0.01, mode="linear"):
    """Eliminates stimulations artifacts from raw data

    The raw object will be modified in place (no copy)

    Parameters
    ----------
    raw: Raw object
        raw data object
    events: array, shape (n_events, 3)
        The list of events
    event_id: int
        The id of the events generating the stimulation artifacts.
    tmin : float
        Start time before event in seconds
    tmax : float
        End time after event in seconds
    mode : 'linear' | 'window'
        way to fill the artifacted time interval
        'linear' does linear interpolation
        'window' applies a (1 - hanning) window

    Returns
    -------
    raw: Raw object
        raw data object
    """
    if not raw._preloaded:
        raise RuntimeError(
            "Modifying data of Raw is only supported "
            "when preloading is used. Use preload=True "
            "(or string) in the constructor."
        )
    events_sel = events[:, 2] == event_id
    event_start = events[events_sel, 0]
    s_start = np.ceil(raw.info["sfreq"] * np.abs(tmin))
    s_end = np.ceil(raw.info["sfreq"] * tmax)

    picks = pick_types(raw.info, meg=True, eeg=True)

    if mode == "window":
        window = 1 - np.r_[signal.hann(4)[:2], np.ones(s_end + s_start - 4), signal.hann(4)[-2:]].T

    for k in range(len(event_start)):
        first_samp = event_start[k] - raw.first_samp - s_start
        last_samp = event_start[k] - raw.first_samp + s_end
        data, _ = raw[picks, first_samp:last_samp]
        if mode == "linear":
            x = np.array([first_samp, last_samp])
            f = interpolate.interp1d(x, data[:, (0, -1)])
            xnew = np.arange(first_samp, last_samp)
            interp_data = f(xnew)
            raw[picks, first_samp:last_samp] = interp_data
        elif mode == "window":
            raw[picks, first_samp:last_samp] = data * window[np.newaxis, :]
    return raw

 def test_basic(self):
     assert_allclose(signal.hann(6, sym=False),
                     [0, 0.25, 0.75, 1.0, 0.75, 0.25])
     assert_allclose(signal.hann(7, sym=False),
                     [0, 0.1882550990706332, 0.6112604669781572,
                      0.9504844339512095, 0.9504844339512095,
                      0.6112604669781572, 0.1882550990706332])
     assert_allclose(signal.hann(6, True),
                     [0, 0.3454915028125263, 0.9045084971874737,
                      0.9045084971874737, 0.3454915028125263, 0])
     assert_allclose(signal.hann(7),
                     [0, 0.25, 0.75, 1.0, 0.75, 0.25, 0])

def _window_evoked(evoked, size):
    """Window evoked (size in seconds)"""
    if isinstance(size, (float, int)):
        lsize = rsize = float(size)
    else:
        lsize, rsize = size
    evoked = deepcopy(evoked)
    sfreq = float(evoked.info["sfreq"])
    lsize = int(lsize * sfreq)
    rsize = int(rsize * sfreq)
    lhann = signal.hann(lsize * 2)
    rhann = signal.hann(rsize * 2)
    window = np.r_[lhann[:lsize], np.ones(len(evoked.times) - lsize - rsize), rhann[-rsize:]]
    evoked.data *= window[None, :]
    return evoked

 def __init__(self,
              X_mean=None,
              X_std=None,
              shuffle=0,
              seq_len=8000,
              use_window=0,
              use_spec=0,
              frame_size=200,
              file_name='accent_tbptt',
              batch_size=64,
              range_start=0,
              range_end=None,
              **kwargs):
     self.X_mean = X_mean
     self.X_std = X_std
     self.shuffle = shuffle
     self.seq_len = seq_len
     self.use_window = use_window
     self.use_spec = use_spec
     self.frame_size = frame_size
     self.file_name = file_name
     if self.use_window:
         if self.use_spec:
             if not is_power2(self.frame_size):
                  raise ValueError("Provide a number which is power of 2,\
                                    for fast speed of DFT.")
         if np.mod(self.frame_size, 2)==0:
             self.overlap = self.frame_size / 2
         else:
             self.overlap = (self.frame_size - 1) / 2
         self.window = signal.hann(self.frame_size)[None, :].astype(theano.config.floatX)
     self.batch_size = batch_size
     self.range_start = range_start
     self.range_end = range_end
     super(Accent_h5, self).__init__(**kwargs)

def data_w_hann(dt,frame=256):
    temp = []
    _t = sig.hann(frame)
    fx = frame*0.5
    #temp = [sum(np.array(dt[x*fx:x*fx+frame]*_t)**2) for x in range(int(len(dt)/fx -1))]
    temp = [np.log(sum(np.abs(dt[x*fx:x*fx+frame]*_t))) for x in range(int(len(dt)/fx -1))]
    return temp

def apodization(mzs,intensities,w_size=10):
    import scipy.signal as signal
    win = signal.hann(w_size)
    win = signal.slepian(w_size,0.3)
    intensities = signal.fftconvolve(intensities, win, mode='same') / sum(win)
    intensities[intensities<1e-6]=0
    return intensities

    def CalculateSpectrumBlock(self, region):
        '''Return the power spectrum of a region based on a Welch-Bartlett method.
        The block used in each FFT is half the length of the total window.
        The step size is half the size of the FFT window.
        Average over A-lines.

        This function assumes the size of the region is divisible by 4.

        It uses a zoomed in FFT to compute the power spectrum.  The zoomed in FFT is given by the
        chirpz transform.
        '''
        from scipy.signal import hann,convolve
        import numpy
        from chirpz import chirpz
        points = region.shape[0]
        points -= points%4
        points /= 2
        #######SAMPLE REGION#############
        maxDataWindow = region[0:2*points, :]

        #compute 3 fourier transforms and average them
        #Cutting off the zero-value end points of the hann window
        #so it matches Matlab's definition of the function
        windowFunc = hann(points+2)[1:-1].reshape(points,1)
        fftSample = numpy.zeros(points)
        for f in range(3):
            dataWindow = maxDataWindow[(points/2)*f:(points/2)*f + points, :]*windowFunc

            for l in range(dataWindow.shape[1]):
                fftSample += abs(chirpz(dataWindow[:,l], self.cztA, self.cztW, points))**2

        return fftSample

    def plot(self):
        self.amostrasporseg=15*5 #samples/sec
        frequenciasinal=5 #Hz
        omega= frequenciasinal
        self.z=2*np.pi*np.arange(0,2*np.pi,1/self.amostrasporseg)
        y=np.sin(self.z*omega)
        k=y*signal.hann(len(y))

        ylinha= 20*np.log10(abs(np.fft.fft(k,2048)))
        ylinha=np.tile(ylinha,3)

        zlinha=np.linspace(-2,4,len(ylinha))
        self.figure.subplots_adjust(bottom=.75)
        gs = gridspec.GridSpec(5, 1,height_ratios=[0.2,1,0.25,1,0.2])
        ax =self.figure.add_subplot(gs[1])
        self.plot2,=plt.plot(zlinha,ylinha)
        plt.title('Espectro do sinal')
        plt.xlabel(r'$\omega$')
        plt.ylabel(r'|X($\omega$)|')

        plt.xticks((-2,-1,0,1,2,3,4),[r'$-2\pi$',r'$-\pi$','0',r'$\pi$',r'$2\pi$',r'$3\pi$',r'$4\pi$'])
        #ax.set_xticks([-0.0442,0.0442], minor=True)
        ax.xaxis.grid(True,which='major',linewidth=0.75,color='k',linestyle='--')
        self.beta=self.figure.add_subplot(gs[3])
        self.plot3,=plt.plot(self.z,y,label='Amostragem Correta')
        plt.plot(self.z,y,'o',label='Amostragem Fixa')
        plt.legend(loc='upper right')
        self.beta.set_xlabel(r't')
        self.beta.set_ylabel(r'x(t)')
        self.beta.set_xlim([0,2*np.pi])
        self.figure.tight_layout()