speech_enhancement1.m

说明小波消噪的理论

clear
clc
%在噪声环境下语音信号的增强
%语音信号为读入的声音文件
%噪声为正态随机噪声
sound = wavread('Voice.wav');
count = length(sound);
noise = 0.05*randn(1,count);
y=sound' + noise;
%用小波函数 'db6'对信号进行3层分解
[c,l] = wavedec(y,3, 'db6');   
%估计尺度1的噪声标准偏差
sigma = wnoisest(c,l,1);      
alpha = 2;
%获取消噪过程中的阀值
thr = wbmpen(c,l,sigma,alpha) ;   
keepapp = 1;
%对信号进行消噪
yd = wdencmp('gbl',c,l,'db6',3,thr,'s',keepapp);
subplot(121);
plot(sound);
title('原始语音信号');
subplot(122);
plot(yd);
title('去噪后的语音信号');