<s>
Livewire	O
,	O
is	O
a	O
segmentation	B-Algorithm
technique	O
which	O
allows	O
a	O
user	O
to	O
select	O
regions	O
of	O
interest	O
to	O
be	O
extracted	O
quickly	O
and	O
accurately	O
,	O
using	O
simple	O
mouse	O
clicks	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
the	O
lowest	B-Algorithm
cost	I-Algorithm
path	I-Algorithm
algorithm	I-Algorithm
,	O
by	O
Edsger	O
W	O
.	O
Dijkstra	O
.	O
</s>
<s>
Firstly	O
convolve	O
the	O
image	O
with	O
a	O
Sobel	B-Algorithm
filter	I-Algorithm
to	O
extract	O
edges	O
.	O
</s>
<s>
In	O
1995	O
,	O
Eric	O
N	O
.	O
Mortensen	O
and	O
William	O
A	O
.	O
Barrett	O
made	O
some	O
extension	O
work	O
on	O
livewire	O
segmentation	B-Algorithm
tool	O
,	O
which	O
is	O
known	O
as	O
Intelligent	O
Scissors	O
.	O
</s>
<s>
Convolve	O
the	O
image	O
with	O
a	O
Sobel	B-Algorithm
filter	I-Algorithm
to	O
extract	O
edges	O
.	O
</s>
<s>
Edges	O
are	O
weighted	O
with	O
features	O
gathered	O
from	O
the	O
Sobel	B-Algorithm
filter	I-Algorithm
making	O
it	O
less	O
costly	O
to	O
stay	O
on	O
an	O
edge	O
.	O
</s>
<s>
This	O
3D	O
extension	O
of	O
Livewire	O
leans	O
heavily	O
on	O
concepts	O
of	O
discrete	B-Algorithm
exterior	I-Algorithm
calculus	I-Algorithm
to	O
reinterpret	O
the	O
2D	O
Livewire	O
algorithm	O
from	O
the	O
standpoint	O
of	O
boundary/coboundary	O
operators	O
and	O
then	O
apply	O
these	O
concepts	O
in	O
3D	O
.	O
</s>
