how to implement this equation

I have a equation,kindly tell how to implement this equation

http://imgur.com/Zw13RbE

Answer 1

[Youssef Khmou]

 hi,

given I and J of size MxN

 M=6;N=4;
 I=rand(M,N);
 J=rand(M,N);
 II=I.^2;
 JJ=J.^2;
 P=I.*J;  %  its Element wise product !!
 numerator=sum(P(:));

 denominator= sqrt(sum(II(:))*sum(JJ(:)));
 NCC=numerator/denominator;

the result should be : 0<=NCC<=1,