How to plot watermark detector response ???????

2012 3 17
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3 次查看（30 天）

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Could anyone help me to plot the '*watermark detector response'* which shows the response of the watermark detector to 1000 randomly generated watermarks of which only one matches the watermark embedded.
Say I - original image; I'- watermarked image ;W - original watermark ; W*- extracted watermark ; And the similarity of the watermarks is found using the code given below:
function SIM=WM_detect(W',W)
SIM=sum(W'.*W)/sqrt(sum(W'.*W));
end
The plot should resemble like in the link given below: http://scien.stanford.edu/pages/labsite/2000/ee368/projects2000/project5/Tests%20and%20Results.htm {The last response plot(using spread spectrum) for rotated & cropped image. }
(or)
<http://www.google.co.in/imgres?q=watermark+detection+matlab&hl=en&biw=1440&bih=785&gbv=2&tbm=isch&tbnid=93CLJJA1fj2TXM:&imgrefurl=http://nalag.cs.kuleuven.be/research/software/FRFT/&docid=LwQRVSfuQtpaZM&imgurl=http://nalag.cs.kuleuven.be/research/software/FRFT/fw3a.jpg&w=560&h=420&ei=JrNlT4qdH8n5rAfL89C8Bw&zoom=1>
Hope to get a response as soon as possible
Thanks a lot.

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Walter Roberson
Walter Roberson 2012-3-17
Which plot there? There are a number, and none of them are clear matches for what you seem to be asking to plot.
mcc mscelec
mcc mscelec 2012-3-17
The last response plot(using spread spectrum) for rotated & cropped image.
Basically I want to plot a graph which shows the response of the watermark detector to 1000 randomly generated watermarks of which only one matches the watermark which i embedded.

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mcc mscelec
mcc mscelec 2012-4-14

1 个投票

Code for WATERMARK DETECTOR RESPONSE FUNCTION
function WM_plot(r,c,ext_wm,orig_wm)
for k=1:1000
wm=randn(r,c);%depending on the size of the watermark
wm=uint8(wm);%if necessary
store(k)=WM_detect(ext_wm,wm);%wrong watermarks
if k == 400
store(k)=WM_detect(ext_wm,orig_wm);%original watermark detection
end
end
figure(1),plot(1:k,[store]),ylabel('Watermark detector response'),xlabel('random watermarks');
hold on
%threshold calculation
[peak,ind]=sort(store,'descend');
threshold=peak(2)+(peak(2)*0.1);%T=second highest peak+10percentof the same
figure(1),plot(1:1000,[threshold],'red');
hold on
figure(1),plot(1:1000,peak(2),'green');
Regards, mcc :)

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