multiplying a weight mask with input matrix

Hi, i am trying to find a way to calculate sum(w(i,j)*A(m+i,n+j)) where w is a 3x3 weight mask , A is the input matrix,m & n size of A,i & j size of w. i have written a function to do this.

    if true
      % code
       function Y = myfun (m,n)
       A=imread('');
        c=0;
       for i=1:3
           for j =1:3
              c=c+A(m+i,n+j)*B(i,j);        
           end
       end
       Y=c;
       end

    end

and a loop to store the values in a matrix C .

if true
  % code
   [x,y]=size(A);
  for m=1:x
     for n=1:y
      C(m,n)=myfun(m,n);
     end
 end
end

But i am getting an index out of bound error. i have considered padding the input matrix but it will change the parameters being passed. Please help me solve this.

Answer 1

[Mohammad Abouali]

use conv2 function

That will get the job done much faster.