H = H/(sum(H(:))+eps);
s1 = sum(H,1);
s2 = sum(H,2);
H = H.*log2((H+eps)./(s2*s1+eps));
mi = sum(H(:));
fprintf('Mutual information: %3.4f\n',mi);

if I want to add the value of

Dear Panatsada,

try the attached function, that is providing either the histogram of one image or the joint 
histogram of two images.

Regards,

Christian

-- 
____________________________________________________________________________

Christian Gaser, Ph.D.
Assistant Professor of Computational Neuroscience
Department of Psychiatry
Friedrich-Schiller-University of Jena
Jahnstrasse 3, D-07743 Jena, Germany
Tel: ++49-3641-934752 Fax: ++49-3641-934755
e-mail: [log in to unmask]
http://dbm.neuro.uni-jena.de

On Thu, 4 Mar 2010 18:24:00 +0000, Panatsada Awikunprasert 
<[log in to unmask]> wrote:

>Dear SPMers,
>Can anyone please tell me how to create a joint histogram?
>I want to measure how good the registration (clinial data)!
  is, can anyone tell, 
>please?
>Thank you very much,
>Panatsada