correlation between images [message #65922] |
Thu, 02 April 2009 05:33  |
Wout De Nolf
Messages: 194 Registered: October 2008
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Senior Member |
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Hi all,
I have two images and I want to check (statistically) whether they are
"the same" and show it to others so they will believe me :-).
The first thing I thought of was using the Pearson correlation
coefficient:
R=correlate(img1,img2)
However, R close to 1 doesn't necessarily means they are "the same" or
in other words, img1 vs. img2 is linear.
( Some examples of R=0.8:
http://upload.wikimedia.org/wikipedia/commons/b/b6/Anscombe. svg)
I can off course show the scatter plot
plot,img1,img2
with LADFIT(img1,img2) to draw a line through it and
correlate(img1,img2) to add a correlation coefficient.
I'm still not satisfied though. Does anyone use another statistical
method to compare images? (I tried IDL's c_correlate but I can't
figure out what the result means...)
Thanks
Wox
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