一種小波包的實例

x=wavread(data); 

fs=16000;

x=lowp(x,2500,3000,0.1,20,fs);%high_bottom=1500
x=highp(x,200,100,0.1,20,fs);%low_top=200


wptree=wpdec(x,7,'db5'); 


for k=47:62 
    wptree=wpjoin(wptree,k); 
end 


for k=79:86 
    wptree=wpjoin(wptree,k); 
end 
for k=91:94 
    wptree=wpjoin(wptree,k);
end 
%plot(wptree); 


sorh='n';%所選閾值函數 %----------- 


for i=0:31
    c70(:,i+1)=wpcoef(wptree,[7 i]); 
    q70=median(abs(c70(:,i+1))); 
    arr70(i+1)=(q70/0.6745).*sqrt(2*log(442)); 
    if(i>0) 
        c70(:,i+1)=wthresh(c70(:,i+1),sorh,arr70(i+1)); 
        wptree=write(wptree,'data',[7 i],c70(:,i+1));
    end 
end 
for i=48:55 
    c71(:,i-47)=wpcoef(wptree,[7 i]); 
    q71=median(abs(c71(:,i-47))); 
    arr71(i-47)=(q71/0.6745).*sqrt(2*log(442)); 
    c71(:,i-47)=wthresh(c71(:,i-47),sorh,arr71(i-47)); 
    wptree=write(wptree,'data',[7 i],c71(:,i-47)); 
end 

for j=16:23 
    c60(:,j-15)=wpcoef(wptree,[6 j]); 
    q60=median(abs(c60(:,j-15))); 
    arr60(j-15)=(q60/0.6745).*sqrt(2*log(876)); 
    c60(:,j-15)=wthresh(c60(:,j-15),sorh,arr60(j-15)); 
    wptree=write(wptree,'data',[6 j],c60(:,j-15));
end 
for j=28:31 
    c61(:,j-27)=wpcoef(wptree,[6 j]); 
    q61=median(abs(c61(:,j-27))); 
    arr61(j-27)=(q61/0.6745).*sqrt(2*log(876)); 
    c61(:,j-27)=wthresh(c61(:,j-27),sorh,arr61(j-27)); 
    wptree=write(wptree,'data',[6 j],c61(:,j-27)); 
end 

for k=16:31 
    c5(:,k-15)=wpcoef(wptree,[5 k]); 
    q5=median(abs(c5(:,k-15))); 
    arr5(k-15)=(q5/0.6745).*sqrt(2*log(1743)); 
    c5(:,k-15)=wthresh(c5(:,k-15),sorh,arr5(k-15)); 
    wptree=write(wptree,'data',[5 k],c5(:,k-15));
end 


y=wprec(wptree);