Python提取频域特征知识点浅析

在多数的现代语音识别系统中，人们都会用到频域特征。梅尔频率倒谱系数（MFCC）,首先计算信号的功率谱，然后用滤波器和离散余弦变换的变换来提取特征。本文重点介绍如何提取MFCC特征。

首先创建有一个python/' target='_blank'>python文件，并导入库文件： from scipy.io import wavfile from Python_speech_features import mfcc, logfbank import matplotlib.pylab as plt1、首先创建有一个Python文件，并导入库文件： from scipy.io import wavfile from python_speech_features import mfcc, logfbank import matplotlib.pylab as plt

读取音频文件：

samplimg_freq, audio = wavfile.read("data/input_freq.wav")

提取MFCC特征和过滤器特征：

mfcc_features = mfcc(audio, samplimg_freq)

filterbank_features = logfbank(audio, samplimg_freq)

打印参数，查看可生成多少个窗体：

   print('\nMFCC:\nNumber of windows =', mfcc_features.shape[0])   print('Length of each feature =', mfcc_features.shape[1])   print('\nFilter bank:\nNumber of windows=', filterbank_features.shape                                                         [0])   print('Length of each feature =', filterbank_features.shape[1])

将MFCC特征可视化。转换矩阵，使得时域是水平的：

   mfcc_features = mfcc_features.T   plt.matshow(mfcc_features)   plt.title('MFCC')

将滤波器组特征可视化。转化矩阵，使得时域是水平的：

   filterbank_features = filterbank_features.T   plt.matshow(filterbank_features)   plt.title('Filter bank')      plt.show()