python 暗弱目标提取
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：
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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：
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mfcc_features = mfcc_features.tplt.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：
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filterbank_features = filterbank_features.tplt.matshow(filterbank_features)plt.title('filter bank')plt.show() |
