<s>
In	O
image	O
Noise	O
reduction	O
,	O
local	B-Algorithm
pixel	I-Algorithm
grouping	I-Algorithm
is	O
the	O
algorithm	O
to	O
remove	O
noise	O
from	O
images	O
using	O
principal	B-Application
component	I-Application
analysis	I-Application
(	O
PCA	O
)	O
.	O
</s>
<s>
PCA	O
works	O
in	O
the	O
way	O
that	O
principal	B-Application
components	I-Application
with	O
larger	O
possible	O
variance	O
are	O
preserved	O
while	O
discarding	O
low	O
variance	O
components	O
.	O
</s>
<s>
Image	O
denoising	O
by	O
principal	B-Application
component	I-Application
analysis	I-Application
with	O
local	O
pixel	O
grouping(LPG-PCA )	O
was	O
developed	O
by	O
Lei	O
et	O
.	O
</s>
<s>
The	O
solution	O
is	O
competitive	O
compared	O
with	O
other	O
algorithms	O
such	O
as	O
Block-matching	B-General_Concept
algorithm	I-General_Concept
.	O
</s>
