<s>
Image	B-Algorithm
restoration	I-Algorithm
is	O
the	O
operation	O
of	O
taking	O
a	O
corrupt/noisy	O
image	O
and	O
estimating	O
the	O
clean	O
,	O
original	O
image	O
.	O
</s>
<s>
Corruption	O
may	O
come	O
in	O
many	O
forms	O
such	O
as	O
motion	O
blur	O
,	O
noise	B-Algorithm
and	O
camera	O
mis-focus	O
.	O
</s>
<s>
Image	B-Algorithm
restoration	I-Algorithm
is	O
performed	O
by	O
reversing	O
the	O
process	O
that	O
blurred	O
the	O
image	O
and	O
such	O
is	O
performed	O
by	O
imaging	O
a	O
point	O
source	O
and	O
use	O
the	O
point	O
source	O
image	O
,	O
which	O
is	O
called	O
the	O
Point	O
Spread	O
Function	O
(	O
PSF	O
)	O
to	O
restore	O
the	O
image	O
information	O
lost	O
to	O
the	O
blurring	O
process	O
.	O
</s>
<s>
Image	B-Algorithm
restoration	I-Algorithm
is	O
different	O
from	O
image	B-Application
enhancement	I-Application
in	O
that	O
the	O
latter	O
is	O
designed	O
to	O
emphasize	O
features	O
of	O
the	O
image	O
that	O
make	O
the	O
image	O
more	O
pleasing	O
to	O
the	O
observer	O
,	O
but	O
not	O
necessarily	O
to	O
produce	O
realistic	O
data	O
from	O
a	O
scientific	O
point	O
of	O
view	O
.	O
</s>
<s>
Image	B-Application
enhancement	I-Application
techniques	O
(	O
like	O
contrast	B-Algorithm
stretching	I-Algorithm
or	O
de-blurring	O
by	O
a	O
nearest	O
neighbor	O
procedure	O
)	O
provided	O
by	O
imaging	O
packages	O
use	O
no	O
a	O
priori	O
model	O
of	O
the	O
process	O
that	O
created	O
the	O
image	O
.	O
</s>
<s>
With	O
image	B-Application
enhancement	I-Application
noise	B-Algorithm
can	O
effectively	O
be	O
removed	O
by	O
sacrificing	O
some	O
resolution	O
,	O
but	O
this	O
is	O
not	O
acceptable	O
in	O
many	O
applications	O
.	O
</s>
<s>
The	O
objective	O
of	O
image	B-Algorithm
restoration	I-Algorithm
techniques	O
is	O
to	O
reduce	O
noise	B-Algorithm
and	O
recover	O
resolution	O
loss	O
.	O
</s>
<s>
The	O
most	O
straightforward	O
and	O
a	O
conventional	O
technique	O
for	O
image	B-Algorithm
restoration	I-Algorithm
is	O
deconvolution	B-Algorithm
,	O
which	O
is	O
performed	O
in	O
the	O
frequency	O
domain	O
and	O
after	O
computing	O
the	O
Fourier	B-Algorithm
transform	I-Algorithm
of	O
both	O
the	O
image	O
and	O
the	O
PSF	O
and	O
undo	O
the	O
resolution	O
loss	O
caused	O
by	O
the	O
blurring	O
factors	O
.	O
</s>
<s>
This	O
deconvolution	B-Algorithm
technique	O
,	O
because	O
of	O
its	O
direct	O
inversion	O
of	O
the	O
PSF	O
which	O
typically	O
has	O
poor	O
matrix	B-Algorithm
condition	I-Algorithm
number	I-Algorithm
,	O
amplifies	O
noise	B-Algorithm
and	O
creates	O
an	O
imperfect	O
deblurred	O
image	O
.	O
</s>
