<s>
Iterative	B-General_Concept
closest	I-General_Concept
point	I-General_Concept
(	O
ICP	O
)	O
is	O
an	O
algorithm	O
employed	O
to	O
minimize	B-Algorithm
the	I-Algorithm
difference	I-Algorithm
between	I-Algorithm
two	I-Algorithm
clouds	I-Algorithm
of	I-Algorithm
points	I-Algorithm
.	O
</s>
<s>
ICP	O
is	O
often	O
used	O
to	O
reconstruct	B-Algorithm
2D	I-Algorithm
or	I-Algorithm
3D	I-Algorithm
surfaces	I-Algorithm
from	O
different	O
scans	O
,	O
to	O
localize	O
robots	O
and	O
achieve	O
optimal	O
path	O
planning	O
(	O
especially	O
when	O
wheel	O
odometry	O
is	O
unreliable	O
due	O
to	O
slippery	O
terrain	O
)	O
,	O
to	O
co-register	O
bone	O
models	O
,	O
etc	O
.	O
</s>
<s>
The	O
Iterative	B-General_Concept
Closest	I-General_Concept
Point	I-General_Concept
algorithm	O
keeps	O
one	O
point	O
cloud	O
,	O
the	O
reference	O
or	O
target	O
,	O
fixed	O
,	O
while	O
transforming	O
the	O
other	O
,	O
the	O
source	O
,	O
to	O
best	O
match	O
the	O
reference	O
.	O
</s>
<s>
ICP	O
is	O
one	O
of	O
the	O
widely	O
used	O
algorithms	O
in	O
aligning	O
three	O
dimensional	O
models	O
given	O
an	O
initial	O
guess	O
of	O
the	O
rigid	B-Algorithm
transformation	I-Algorithm
required	O
.	O
</s>
<s>
The	O
Iterative	B-General_Concept
Closest	I-General_Concept
Point	I-General_Concept
algorithm	O
contrasts	O
with	O
the	O
Kabsch	B-Algorithm
algorithm	I-Algorithm
and	O
other	O
solutions	O
to	O
the	O
orthogonal	O
Procrustes	O
problem	O
in	O
that	O
the	O
Kabsch	B-Algorithm
algorithm	I-Algorithm
requires	O
correspondence	O
between	O
point	O
sets	O
as	O
an	O
input	O
,	O
whereas	O
Iterative	B-General_Concept
Closest	I-General_Concept
Point	I-General_Concept
treats	O
correspondence	O
as	O
a	O
variable	O
to	O
be	O
estimated	O
.	O
</s>
<s>
Iterate	B-Algorithm
(	O
re-associate	O
the	O
points	O
,	O
and	O
so	O
on	O
)	O
.	O
</s>
<s>
Zhang	O
proposes	O
a	O
modified	O
k-d	B-Data_Structure
tree	I-Data_Structure
algorithm	O
for	O
efficient	O
closest	O
point	O
computation	O
.	O
</s>
<s>
MeshLab	B-Language
an	O
open	O
source	O
mesh	O
processing	O
tool	O
that	O
includes	O
a	O
GNU	O
General	O
Public	O
License	O
implementation	O
of	O
the	O
ICP	O
algorithm	O
.	O
</s>
<s>
CloudCompare	B-Language
an	O
open	O
source	O
point	O
and	O
model	O
processing	O
tool	O
that	O
includes	O
an	O
implementation	O
of	O
the	O
ICP	O
algorithm	O
.	O
</s>
<s>
PCL	B-Language
(	O
Point	B-Language
Cloud	I-Language
Library	I-Language
)	O
is	O
an	O
open-source	O
framework	O
for	O
n-dimensional	O
point	O
clouds	O
and	O
3D	O
geometry	O
processing	O
.	O
</s>
<s>
Open	O
source	O
C++	O
implementations	O
of	O
the	O
ICP	O
algorithm	O
are	O
available	O
in	O
VTK	B-Language
,	O
ITK	B-Language
and	O
libraries	O
.	O
</s>
