fill a matrix from an im age

 val=zeros(R,C);
  val=double(val);
  val(1,1)=img(1,2)+img(2,2)+img(2,1);
  val(1,C)=img(1,C-1)+img(2,C-1)+img(2,C);
  val(R,1)=img(R,2)+img(R-1,1)+img(R-1,2);
  val(R,C)=img(R,C-1)+img(R-1,C)+img(R-1,C-1);
  for i=2:C-1
      val(1,i)=abs(img(1,i+1)-img(1,i-1))+img(2,i-1)+img(2,i)+img(2,i+1);
      val(R,i)=abs(img(R,i+1)-img(R,i-1))+img(R-1,i-1)+img(R-1,i)+img(R-1,i+1);
  end
%%img a grayscale image
%%[R,C]=size(img)
%%this code gives me a wrong results can any one help me???????????

[Sven]

The results look right to me.

But wait, you say... how can this guy know that the results are right? I haven't even described what I'm looking for!

... exactly.