Filter Rerata Input manual

clear all;
clc;
I=[170 240 10 80 150;
    230 50 70 140 160;
    40 60 130 200 220;
    100 120 190 210 30;
    110 180 250 20 90];
[m n] = size(I);
for x = 2:(m-1)
    for y = 2:(n-1)
        K(x-1, y-1) = I((x-1), (y-1))/9 + I((x-1),y)/9 + I((x-1), (y+1))/9 ...
            + I(x,(y-1))/9 + I(x,y)/9 + I(x,(y+1))/9 ...
            + I((x+1),(y-1))/9 + I((x+1),y)/9 + I((x+1),(y+1))/9;
        K(x-1,y-1) = fix(K(x-1,y-1));
    end
end
I
K