MFCC参数提取MATLAB实例.doc

close all
clear
clc
[x fs]=wavread('speech.wav');
bank=mel(24,256,fs,0,0.4,'m');%Mel滤波器的阶数为24，fft变换的长度为256，采样频率为8000Hz
% 归一化mel滤波器组系数
bank=full(bank);
bank=bank/max(bank(:));
% DCT系数,12*24
for k=1:12
n=0:23; dctcoef(k,:)=cos((2*n+1)*k*pi/(2*24));
end
% 归一化倒谱提升窗口
w = 1 + 6 * sin(pi * [1:12] ./ 12);
w = w/max(w);
% 预加重滤波器
xx=double(x);
xx=filter([1 -0.9375],1,xx);
% 语音信号分帧
xx=enframe(xx,256,80);%对x 256点分为一帧
% 计算每帧的MFCC参数
for i=1:size(xx,1)
y = xx(i,:);
s = y' .* hamming(256);
t = abs(fft(s));%fft快速傅立叶变换
t = t.^2;
c1=dctcoef * log(bank * t(1:129));
c2 = c1.*w';
m(i,:)=c2';
end
%求取差分系数
dtm = zeros(size(m));
for i=3:size(m,1)-2
dtm(i,:) = -2*m(i-2,:) - m(i-1,:) + m(i+1,:) + 2*m(i+2,:);
end
dtm = dtm / 3;
%合并mfcc参数和一阶差分mfcc参数
ccc = [m dtm];
%去除首尾两帧，因为这两帧的一阶差分参数为0
ccc = ccc(3:size(m,1)-2,:);
subplot(211)
ccc_1=ccc(:,1);
plot(ccc_1);title('MFCC');
ylabel('幅值');
[h,w]=size(ccc);
A=size(ccc);
subplot(212)
plot([1,w],A);
xlabel('维数');
ylabel('幅值');
title('维数于幅值的关系')