clear;
I2=imread('tire.tif');
imshow(I2)
I=double(I2);
[m,n]=size(I2);
for x=2:m-1
   for y=2:n-1
      I1(2*x-3,2*y-3)=(1/3)*(I(x,y)+I(x-1,y)+I(x,y-1));
      I1(2*x-2,2*y-3)=(1/3)*(I(x,y)+I(x+1,y)+I(x,y-1));
      I1(2*x-3,2*y-2)=(1/3)*(I(x,y)+I(x,y+1)+I(x-1,y));
      I1(2*x-2,2*y-2)=(1/3)*(I(x,y)+I(x+1,y)+I(x,y+1));
   end
end
I3=uint8(I1);
figure,imshow(I3)