****************************************** 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('c12345.wav'); count1=length(sound); noise=0.05*randn(1,count1); for i=1:count1 signal(i)=sound(i); end for i=1:count1 y(i)=signal(i)+noise(i); end %在小波基'db3'下进行一维离散小波变换 [coefs1,coefs2]=dwt(y,'db3'); %[低频 高频] count2=length(coefs1); count3=length(coefs2); energy1=sum((abs(coefs1)).^2); energy2=sum((abs(coefs2)).^2); energy3=energy1+energy2; for i=1:count2 recoefs1(i)=coefs1(i)/energy3; end 

for i=1:count3 recoefs2(i)=coefs2(i)/energy3; end %低频系数进行语音信号清浊音的判别 zhen=160; count4=fix(count2/zhen); for i=1:count4 n=160*(i-1)+1:160+160*(i-1); s=sound(n); w=hamming(160); sw=s.*w; a=aryule(sw,10); sw=filter(a,1,sw); sw=sw/sum(sw); r=xcorr(sw,'biased'); corr=max(r); %为清音（unvoice）时，输出为 1；为浊音（voice）时，输出为 0 if corr>=0.8 output1(i)=0; elseif corr<=0.1 output1(i)=1; end end for i=1:count4 n=160*(i-1)+1:160+160*(i-1); if output1(i)==1 switch abs(recoefs1(i)) case abs(recoefs1(i))<=0.002 

recoefs1(i)=0; case abs(recoefs1(i))>0.002 & abs(recoefs1(i))<=0.003 recoefs1(i)=sgn(recoefs1(i))*(0.003*abs(recoefs1(i))-0.000003)/0.002; otherwise recoefs1(i)=recoefs1(i); end elseif output1(i)==0 recoefs1(i)=recoefs1(i); end end %对高频系数进行语音信号清浊音的判别 count5=fix(count3/zhen); for i=1:count5 n=160*(i-1)+1:160+160*(i-1); s=sound(n); w=hamming(160); sw=s.*w; a=aryule(sw,10); sw=filter(a,1,sw); sw=sw/sum(sw); r=xcorr(sw,'biased'); corr=max(r); %为清音（unvoice）时，输出为 1；为浊音（voice）时，输出为 0 if corr>=0.8 output2(i)=0; elseif corr<=0.1 output2(i)=1; end end 

for i=1:count5 n=160*(i-1)+1:160+160*(i-1); if output2(i)==1 switch abs(recoefs2(i)) case abs(recoefs2(i))<=0.002 recoefs2(i)=0; case abs(recoefs2(i))>0.002 & abs(recoefs2(i))<=0.003 recoefs2(i)=sgn(recoefs2(i))*(0.003*abs(recoefs2(i))-0.000003)/0.002; otherwise recoefs2(i)=recoefs2(i); end elseif output2(i)==0 recoefs2(i)=recoefs2(i); end end %在小波基'db3'下进行一维离散小波反变换 output3=idwt(recoefs1, recoefs2,'db3'); %对输出信号抽样点值进行归一化处理 maxdata=max(output3); output4=output3/maxdata; %读出带噪语音信号，存为'101.wav' wavwrite(y,5500,16,'c101'); %读出处理后语音信号，存为'102.wav' wavwrite(output4,5500,16,'c102');