<s>
In	O
computer	B-Application
vision	I-Application
and	O
image	B-Algorithm
processing	I-Algorithm
a	O
neighborhood	B-Algorithm
operation	I-Algorithm
is	O
a	O
commonly	O
used	O
class	O
of	O
computations	O
on	O
image	O
data	O
which	O
implies	O
that	O
it	O
is	O
processed	O
according	O
to	O
the	O
following	O
pseudo	O
code	O
:	O
</s>
<s>
The	O
result	O
of	O
applying	O
a	O
neighborhood	B-Algorithm
operation	I-Algorithm
on	O
an	O
image	O
is	O
again	O
something	O
which	O
can	O
be	O
interpreted	O
as	O
an	O
image	O
,	O
it	O
has	O
the	O
same	O
dimension	O
as	O
the	O
original	O
data	O
.	O
</s>
<s>
The	O
most	O
common	O
examples	O
of	O
a	O
neighborhood	B-Algorithm
operation	I-Algorithm
use	O
a	O
fixed	O
function	O
which	O
in	O
addition	O
is	O
linear	O
,	O
that	O
is	O
,	O
the	O
computation	O
consists	O
of	O
a	O
linear	O
shift	O
invariant	O
operation	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
the	O
neighborhood	B-Algorithm
operation	I-Algorithm
corresponds	O
to	O
the	O
convolution	B-Language
operation	O
.	O
</s>
<s>
A	O
typical	O
example	O
is	O
convolution	B-Language
with	O
a	O
low-pass	O
filter	O
,	O
where	O
the	O
result	O
can	O
be	O
interpreted	O
in	O
terms	O
of	O
local	O
averages	O
of	O
the	O
image	O
data	O
around	O
each	O
image	O
point	O
.	O
</s>
<s>
The	O
result	O
is	O
similar	O
to	O
a	O
convolution	B-Language
with	O
a	O
low-pass	O
filter	O
with	O
the	O
added	O
effect	O
of	O
preserving	O
sharp	O
edges	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
class	O
of	O
neighborhood	B-Algorithm
operations	I-Algorithm
in	O
which	O
the	O
function	O
has	O
additional	O
parameters	O
which	O
can	O
vary	O
with	O
:	O
</s>
<s>
The	O
pseudo	O
code	O
given	O
above	O
suggests	O
that	O
a	O
neighborhood	B-Algorithm
operation	I-Algorithm
is	O
implemented	O
in	O
terms	O
of	O
an	O
outer	O
loop	O
over	O
all	O
image	O
points	O
.	O
</s>
<s>
The	O
implementation	O
of	O
this	O
neighborhood	B-Algorithm
operation	I-Algorithm
can	O
then	O
be	O
made	O
by	O
having	O
the	O
summation	O
loop	O
outside	O
the	O
loop	O
over	O
all	O
image	O
points	O
.	O
</s>
<s>
An	O
important	O
issue	O
related	O
to	O
neighborhood	B-Algorithm
operation	I-Algorithm
is	O
how	O
to	O
deal	O
with	O
the	O
fact	O
that	O
the	O
neighborhood	O
becomes	O
more	O
or	O
less	O
undefined	O
for	O
points	O
close	O
to	O
the	O
edge	O
or	O
border	O
of	O
the	O
image	O
data	O
.	O
</s>
