Implementing Watermarking DWT bad result?

I tried to implement this journal on matlab, i finally finish the code but sometimes it still give wrong output. I wanted to ask if i missed something in my code from the journal?
Embedding method :
f=wavread('classic1.wav','double');
if mod(length(f),2)~=0
f=[f 0];
end
rawsignal=f;
leftchanel=f(1:size(f),1);
rightchanel=f(1:size(f),2);
[cA1,cD1] = dwt(leftchanel,'haar');
[cA2,cD2] = dwt(cA1,'haar');
[cA3,cD3] = dwt(cA2,'haar');
l_crop=mod(length(cD3),10);
crop=cD3(end-(l_crop-1):end);
segmentT=cD3(1:end-(l_crop));
segment=buffer(segmentT,10);
m=1:10;
sumS=sum(abs(segment(m,:)));
c=sumS/10;
k=6;
l=1;
alpha=2;
Watermark='Test watermarking';
word = char(Watermark);
binary = dec2bin(word,8);
binary_t=transpose(binary);
bin=binary_t(:)-'0';
[X,Y]=size(segment);
for i=1:Y
if(l==length(bin)+1), break, end
for j=1:X
if(l==length(bin)+1), break, end
if(c(i)==0), break,end
if (abs(segment(j,i)/c(i))<(k)) && (abs(segment(j,i)/c(i))>-(k) )
if(bin(l)==1)
segment(j,i)=c(i).*alpha;
l=l+1;
elseif (bin(l)==0)
segment(j,i)=-(c(i)).*alpha;
l=l+1;
end
else
if(l==length(bin)+1), break, end
segment(j,i)=segment(j,i);
end
end
end
segmentd3=segment(:);
segmentd3(end+1:end+l_crop)=crop;
cA2=idwt(cA3,segmentd3,'haar');
cA1=idwt(cA2,cD2,'haar');
leftchanel_recon=idwt(cA1,cD1,'haar');
watermarked2=[leftchanel_recon,rightchanel];
hasil=(rawsignal-watermarked2);
wavwrite(watermarked2,44100,'watermarked.wav');
Extracting method :
f=wavread('watermarked.wav','double');
if mod(length(f),2)~=0
f=[f 0];
end
rawsignal=f;
leftchanel=f(1:size(f),1);
rightchanel=f(1:size(f),2);
[cA1,cD1] = dwt(leftchanel,'haar');
[cA2,cD2] = dwt(cA1,'haar');
[cA3,cD3] = dwt(cA2,'haar');
l_crop=mod(length(cD3),10);
crop=cD3(end-(l_crop-1):end);
segmentT=cD3(1:end-(l_crop));
segment=buffer(segmentT,10);
m=1:10;
sumS=sum(abs(segment(m,:)));
c=sumS/10;
k=6;
l=1;
alpha=2;
con=(k+alpha)/2;
[X,Y]=size(segment);
for i=1:Y
if(l==209), break, end
for j=1:X
if(l==209), break, end
if(c(i)==0), break,end
if (segment(j,i)/c(i)<(k)) && (segment(j,i)/c(i)>-(k) )
if (segment(j,i)/c(i)<=con) && (segment(j,i)/c(i)>=0)
watermark(l,1)=1;
l=l+1;
elseif (segment(j,i)/c(i)>=-con) && (segment(j,i)/c(i)<0)
watermark(l,1)=0;
l=l+1;
end
end
end
end
hasil=char(bin2dec(reshape(num2str(watermark),8,[]).')).';

1 Comment

Hi, Have you been able to get the correct output? Regards

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on 13 May 2013

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