Question

write a matlab code to calculate the correlation coefficient for five neighboring pixels an in an image
preferable ( 256 x 256 ) lena image

Answer 1

  m1 = A(:,1:end-1,1);  %# All rows and columns 1 through 255 
           n1 = A(:,2:end,1);    %# All rows and columns 2 through 256 
                                 % A is the original image

           randIndex1 = randperm(numel(m1));  %# A random permutation of the integers
                                              %#   from 1 to numel(m1)
           randIndex1 = randIndex1(1:3000);   %# Pick the first 3000 indices
           m1Rand = m1(randIndex1);          %# 3000 random values from m1
           n1Rand = n1(randIndex1);          %# The corresponding 3000 values from n1 

           r_mn1 = corrcoef(m1Rand(:),n1Rand(:)); disp('r_mn1=');disp(r_mn1);