谱减法降噪的matlab代码实现
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谱减法降噪的matlab代码实现
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clc;clear;close all;
winsize=256;%窗長(zhǎng)
n=0.2;%噪聲水平
a=2;
b=5;
c=0.01;
fs=44100;
[speech,fs,nbits]=wavread('file_1.wav') ;%讀入wav文件
sound(speech,fs) ;
pause(5);
size=length(speech);%語(yǔ)音長(zhǎng)度
numofwin=floor(size/winsize);%窗數(shù)
%定義漢明窗
ham=hamming(winsize)';
hamwin=zeros(1,size);
enhanced=zeros(1,size);
improved=zeros(1,size);
%生成噪聲信號(hào)y=speech(:,1)'+n*randn(1,size)
sound(y,fs) ;
pause(5);
%噪聲處理
noisy=n*randn(1,winsize);
Q=fft(speech);
N=fft(noisy);
npow=abs(N);
for q=1:2*numofwin-1
yframe=y(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2);%分幀
hamwin(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)=hamwin(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)+ham;%
%加噪信號(hào)FFT
y1=fft(yframe.*ham);
ypow=abs(y1);%加噪信號(hào)幅度
yangle=angle(y1);%相位
%計(jì)算功率譜密度
Py=ypow.^2;
Pn=npow.^2;
Pyy=ypow.^a;
Pnn=npow.^a;
%基本譜減
for i=1:winsize
if Py(i)-Pn(i)>0
Ps(i)=Py(i)-Pn(i);
else
Ps(i)=0;
end
end
s=sqrt(Ps).*exp(j*yangle);
for i=1:winsize
if Pyy(i)-b*Pnn(i)>0
Pss(i)=Pyy(i)-b*Pnn(i);
else
Pss(i)=c*Pnn(i);
end
end
ss=Pss.^(1/a).*exp(j*yangle);
%去噪語(yǔ)音IFFT
enhanced(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)=enhanced(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)+real(ifft(s));
improved(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)=improved(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)+real(ifft(ss));
end
%去除漢明窗引起的增益
for i=1:size
if hamwin(i)==0
enhanced(i)=0;
improved(i)=0;
else
enhanced(i)=enhanced(i)/hamwin(i);
improved(i)=improved(i)/hamwin(i);
end
end
SNR1=10*log10(var(speech(:,1)')/var(noisy));%加噪語(yǔ)音信噪比
SNR2=10*log10(var(speech(:,1)')/var(enhanced-speech(:,1)'));%增強(qiáng)語(yǔ)音信噪比
SNR3=10*log10(var(speech(:,1)')/var(improved-speech(:,1)'));
figure(1);subplot(2,1,1);plot(speech);%原始語(yǔ)音波形
axis([0 150000 -2 2]);
title(['Original Voice(n=',num2str(n),')']);
figure(1);subplot(2,1,2);plot(y);
title(['Noise Added(SNR=',num2str(SNR1),'dB)']);
figure(2);subplot(2,1,1);plot(enhanced);
title(['Enhanced Voice(SNR=',num2str(SNR2),'dB)']);
figure(2);subplot(2,1,2);plot(improved);
title(['Improved Voice(SNR=',num2str(SNR3),'dB)']);
figure(3);subplot(2,1,1);plot(abs(Q));
title('原信號(hào)fft頻譜');
figure(3);subplot(2,1,2);plot(abs(N));
title('噪聲信號(hào)fft頻譜');
sound(enhanced,fs) ;
pause(5);
sound(improved,fs) ;
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