clc;clear;close all; winsize=256;%窗長 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);%語音長度 numofwin=floor(size/winsize);%窗數 %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FFT y1=fft(yframe.*ham); ypow=abs(y1);%加噪信號幅度 yangle=angle(y1);%相位 %計算功率譜密度 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));%加噪語音信噪比 SNR2=10*log10(var(speech(:,1)')/var(enhanced-speech(:,1)'));%增強語音信噪比 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fft頻譜'); figure(3);subplot(2,1,2);plot(abs(N)); title('噪聲信號fft頻譜'); sound(enhanced,fs) ; pause(5); sound(improved,fs) ;

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