i=imread('peppers.png');
[m n]=size(i)
mask=ones(3,3)/9;
in=zeros([m n]);
for k=1:1:m-1
for l=1:1:n-1
t=i(k-1,l-1)*mask(1,1)+i(k-1,l)*mask(1,2)+i(k-1,l+1)*mask(1,3)+i(k,l-1)*mask(2,1)+i(k,l)*mask(2,2)+i(k,l+1)*mask(2,3)+i(k+1,l-1)*mask(3,1)+i(k+1,l)*mask(3,2)+i(k+1,l+1)*mask(3,3)
in(k,l)=t
im2double(in)
end
end
The problem above occurs when
k = 1
and
l = 1
When looking at a specific index in the matrix i,
i(k-1,l-1)
you get
i(0,0)
which does not exist.
You could try:
for k=2:1:m-1
for l=2:1:n-1
t=i(k-1,l-1)*mask(1,1)+i(k-1,l)*mask(1,2)+i(k-1,l+1)*mask(1,3)+i(k,l-1)*mask(2,1)+i(k,l)*mask(2,2)+i(k,l+1)*mask(2,3)+i(k+1,l-1)*mask(3,1)+i(k+1,l)*mask(3,2)+i(k+1,l+1)*mask(3,3)
in(k,l)=t
im2double(in)
end
end
