<s>
Scan	B-General_Concept
conversion	I-General_Concept
or	O
scan	O
converting	O
rate	O
is	O
a	O
video	O
processing	O
technique	O
for	O
changing	O
the	O
vertical	O
/	O
horizontal	O
scan	O
frequency	O
of	O
video	O
signal	O
for	O
different	O
purposes	O
and	O
applications	O
.	O
</s>
<s>
The	O
device	O
which	O
performs	O
this	O
conversion	O
is	O
called	O
a	O
scan	B-General_Concept
converter	I-General_Concept
.	O
</s>
<s>
The	O
application	O
of	O
scan	B-General_Concept
conversion	I-General_Concept
is	O
wide	O
and	O
covers	O
video	O
projectors	O
,	O
cinema	O
equipment	O
,	O
TV	O
and	O
video	B-General_Concept
capture	I-General_Concept
cards	O
,	O
standard	O
and	O
HDTV	O
televisions	O
,	O
LCD	B-Device
monitors	I-Device
,	O
radar	O
displays	O
and	O
many	O
different	O
aspects	O
of	O
picture	O
processing	O
.	O
</s>
<s>
Scan	B-General_Concept
conversion	I-General_Concept
involves	O
changing	O
the	O
picture	O
information	O
data	O
rate	O
and	O
wrapping	O
the	O
new	O
picture	O
in	O
appropriate	O
synchronization	O
signals	O
.	O
</s>
<s>
It	O
may	O
also	O
be	O
performed	O
using	O
a	O
specialized	O
scan	B-General_Concept
converter	I-General_Concept
vacuum	O
tube	O
.	O
</s>
<s>
In	O
this	O
method	O
,	O
a	O
picture	O
is	O
stored	O
in	O
a	O
line	O
or	O
frame	O
buffer	O
with	O
n1	O
speed	O
(	O
data	O
rate	O
)	O
and	O
is	O
read	O
with	O
n2	O
speed	O
,	O
several	O
picture	O
processing	O
techniques	O
are	O
applicable	O
when	O
the	O
picture	O
is	O
stored	O
in	O
buffer	O
memory	O
including	O
kinds	O
of	O
interpolation	B-Algorithm
from	O
simple	O
to	O
smart	O
high	O
order	O
comparisons	O
,	O
motion	O
detection	O
and	O
…	O
to	O
improve	O
the	O
picture	O
quality	O
and	O
prevent	O
the	O
conversion	O
artifacts	O
.	O
</s>
<s>
Up	O
conversion	O
(	O
interpolation	B-Algorithm
)	O
:	O
</s>
<s>
In	O
many	O
LCD	B-Device
monitors	I-Device
there	O
is	O
a	O
native	O
picture	O
mode	O
,	O
however	O
the	O
monitor	O
can	O
display	O
different	O
graphical	O
modes	O
using	O
a	O
scan	B-General_Concept
converter	I-General_Concept
.	O
</s>
<s>
In	O
a	O
100	O
Hz/120Hz	O
analog	O
TV	O
,	O
there	O
is	O
a	O
scan	B-General_Concept
converter	I-General_Concept
circuit	O
which	O
converts	O
the	O
vertical	O
frequency	O
(	O
refresh	O
rate	O
)	O
from	O
standard	O
50/60Hz	O
to	O
100/120Hz	O
to	O
achieve	O
a	O
low	O
level	O
of	O
flicker	O
which	O
is	O
important	O
in	O
large	O
screen	O
(	O
high	O
inch	O
)	O
TVs	O
.	O
</s>
<s>
Down	O
conversion	O
(	O
decimation	B-Algorithm
)	O
:	O
</s>
<s>
Many	O
graphic	B-Device
cards	I-Device
have	O
output	O
for	O
standard-definition	B-Device
television	I-Device
.	O
</s>
<s>
Other	O
graphic	B-Device
cards	I-Device
lack	O
an	O
SDTV	B-Device
output	O
,	O
but	O
their	O
VGA	O
outputs	O
can	O
still	O
be	O
connected	O
to	O
an	O
SDTV	B-Device
through	O
an	O
external	O
scan	B-General_Concept
converter	I-General_Concept
(	O
pictured	O
)	O
.	O
</s>
<s>
Scan	B-General_Concept
conversion	I-General_Concept
serves	O
as	O
a	O
bridge	O
between	O
TV	O
and	O
computer	O
graphics	O
technology	O
.	O
</s>
