【杨勇】小论文MATLAB实验程序主要部分代码--语音增强--stsa_weuclid1

摘要: stsa_weuclid1

function stsa_weuclid1(filename,outfile,p)

if nargin<3
fprintf('Usage: stsa_weuclid inFile outFile.wav p \n\n');
return;
end

fp=fopen(filename,'r');
if fp<=0, error('Unable to open input file'); end;

% ------------ get the file extension, and then read the whole file -----------
%
ind1=find(filename == '.');
if length(ind1)>1, ind=ind1(length(ind1)); else, ind=ind1; end;
ext = lower(filename(ind+1:length(filename)));

[HDRSIZE, Srate, bpsa, ftype] = gethdr(fp,ext);
x=fread(fp,inf,'short');
fclose(fp);

%x=x/32768;

% =============== Initialize variables ===============
%

len=floor(20Srate/1000); % Frame size in samples
if rem(len,2)==1, len=len+1; end;
PERC=50; % window overlap in percent of frame size
len1=floor(lenPERC/100);
len2=len-len1;

win=hanning(len); %tukey(len,PERC); % define window
U=norm(win);

% Noise magnitude calculations - assuming that the first 6 frames is noise/silence
%
nFFT=len;
nFFT2=len/2;
noise_mean=zeros(nFFT,1);
j=1;
for k=1:5
noise_mean=noise_mean+abs(fft(win.*x(j:j+len-1),nFFT)/U);
j=j+len;
end
noise_mu=noise_mean/5;
noise_mu2=noise_mu.^2;

%--- allocate memory and initialize various variables

k=1;
img=sqrt(-1);
x_old=zeros(len1,1);
Nframes=floor(length(x)/len2)-1;
xfinal=zeros(Nframes*len2,1);

fr=Srate/nFFT;
fIndx=1:floor(4000/fr);
freqs=0:fr:(4000-fr);

%=============================== Start Processing =======================================================
%
k=1;
aa=0.98;
c=sqrt(pi)/2;
ksi_ar=zeros(Nframes,1);
gam_ar=ksi_ar;
C2=gamma(0.5);

%p=-1.0;
CC=gamma(0.6)/gamma(0.1);
STSA=0;
for n=1:Nframes

insign=win.*x(k:k+len-1);

%--- Take fourier transform of frame

spec=fft(insign,nFFT)/U;

sig=abs(spec); % compute the magnitude
sig2=sig.^2;

gammak=min(sig2./noise_mu2,40);  % post SNR
if n==1
ksi=aa+(1-aa)*max(gammak-1,0);
else

ksi=aa*Xk_prev./noise_mu2 + (1-aa)*max(gammak-1,0);     % a priori SNR
%ksi=max(gammak-1,0);
end

vv=0.6;
vk=ksi.*gammak./(vv+ksi);

%----- weighted Euclidean distance ------------------------
numer=CC*sqrt(vk).*confhyperg(0.6,1,vk,100);
denom=gammak.*confhyperg(0.1,1,vk,100);
hw=numer./denom;

%hw2=CC*sqrt(vk)./(gammak.*exp(-vk/2).*besseli(0,vk/2));  % if p=-1

%
% ---- for the cosh measure

% numer = sqrt(gamma(1.5)*vk.*confhyperg(-0.5,1,-vk,40));
% denom = gammak.*sqrt(gamma(0.5)*confhyperg(0.5,1,-vk,40));
% hw=numer./denom;

% --- for the weighted cosh measure
%CC2=gamma((p+3)/2)/gamma((p+1)/2);
%numer=CC2*sqrt(vk).*sqrt(confhyperg(-(p+1)/2,1,-vk,40));
%denom=gammak.*sqrt(confhyperg(-(p-1)/2,1,-vk,40));
%hw=numer./denom;

sig=sig.*hw;
Xk_prev=sig.^2;

xi_w= ifft( hw .* spec);
xi_w= real( xi_w)*U;

% --- Overlap and add ---------------
%
xfinal(k:k+ len2-1)= x_old+ xi_w(1:len1);
x_old= xi_w(len1+ 1: len);

k=k+len2;
end
%========================================================================================

if max(abs(xfinal))>32768
xfinal=xfinal*24000/max(abs(xfinal));
fprintf('Max amplitude exceeded 32768 for file %s\n',filename);

end
xfinal=xfinal/32768;

wavwrite(xfinal,Srate,16,outfile);

return;

% -------- plot SNR ---------------
%
timex=0:1000/Srate:Nframes*10;
subplot(2,1,1),h=plot(timex,x(1:length(timex)));
set(gca,'Box','off','Xlim',[0 timex(length(timex))],'FontSize',12);
ylabel('Amplitude');

time2=0:10:(Nframes-1)10;
subplot(2,1,2),
plot(time2,10log10(hgain));

h=plot(time2,10log10(ksi_ar),'b',time2,10log10(gam_ar),'r:');

legend('\xi_k','\gamma_k-1');
set(h,'Linewidth',1.5);
set(gca,'FontSize',12,'Box','off','Xlim',[0 time2(length(time2))],'Ylim',[-25 max(10*log10(gam_ar))]);
xlabel('Time (ms)');
ylabel(' SNR (dB)');

return;

subplot(3,1,3), %h=plot(time2,20*log10(hgain));

h=plot(20*log10(hgain));
%set(gca,'Box','off','Xlim',[0 timex(length(timex))],'FontSize',12);
ylabel('Amplitude');