0

使用此数据集https://philharmonia.co.uk/resources/sound-samples/我正在尝试绘制特定乐器演奏的音符的功率谱。

我正在使用 librosa 加载音频文件并使用此代码获取一些信息

y, sr = librosa.load(file_path)
duration = librosa.get_duration(y=y, sr=sr)
delta_t = duration / len(y)
t0=0
time = np.arange(0, len(y)) * delta_t + t0

我也在关注这个https://ataspinar.com/2018/12/21/a-guide-for-using-the-wavelet-transform-in-machine-learning/指南来绘制功率谱，我是使用 pywavelet 库。

我在这段代码中遇到的问题是 RuntimeWarning: 除以零在 log2 中遇到，并且未显示该图。

def plot_wavelet(time, signal, scales, 
                 waveletname = 'cmor', 
                 cmap = plt.cm.seismic, 
                 title = 'Wavelet Transform (Power Spectrum) of signal', 
                 ylabel = 'Period (years)', 
                 xlabel = 'Time'):
    
    dt = time[1] - time[0]
    print("dt ", dt)
    [coefficients, frequencies] = pywt.cwt(signal, scales, waveletname, dt)
    power = (abs(coefficients)) ** 2
    period = 1. / frequencies
    levels = [0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8]
    contourlevels = np.log2(levels)
    
    fig, ax = plt.subplots(figsize=(15, 10))
    im = ax.contourf(time, np.log2(period), np.log2(power), contourlevels, extend='both',cmap=cmap)
    

    ax.set_title(title, fontsize=20)
    ax.set_ylabel(ylabel, fontsize=18)
    ax.set_xlabel(xlabel, fontsize=18)
    
    yticks = 2**np.arange(np.ceil(np.log2(period.min())), np.ceil(np.log2(period.max())))
    ax.set_yticks(np.log2(yticks))
    ax.set_yticklabels(yticks)
    ax.invert_yaxis()
    ylim = ax.get_ylim()
    ax.set_ylim(ylim[0], -1)
    
    cbar_ax = fig.add_axes([0.95, 0.5, 0.03, 0.25])
    fig.colorbar(im, cax=cbar_ax, orientation="vertical")
    plt.show()

scales = np.arange(1, 128)
plot_wavelet(time=time, signal=y, scales=scales, waveletname='gaus5')

请注意，幂数组中的某些值位于 -inf。我该如何解决？

4

0 回答 0