<s>
A	O
scan	B-Algorithm
line	I-Algorithm
(	O
also	O
scanline	B-Algorithm
)	O
is	O
one	O
line	O
,	O
or	O
row	O
,	O
in	O
a	O
raster	O
scanning	O
pattern	O
,	O
such	O
as	O
a	O
line	O
of	O
video	O
on	O
a	O
cathode	B-Device
ray	I-Device
tube	I-Device
(	O
CRT	O
)	O
display	O
of	O
a	O
television	O
set	O
or	O
computer	B-Device
monitor	I-Device
.	O
</s>
<s>
On	O
CRT	B-Device
screens	I-Device
the	O
horizontal	O
scan	B-Algorithm
lines	I-Algorithm
are	O
visually	O
discernible	O
,	O
even	O
when	O
viewed	O
from	O
a	O
distance	O
,	O
as	O
alternating	O
colored	O
lines	O
and	O
black	O
lines	O
,	O
especially	O
when	O
a	O
progressive	B-Device
scan	I-Device
signal	O
with	O
below	O
maximum	O
vertical	O
resolution	O
is	O
displayed	O
.	O
</s>
<s>
The	O
term	O
is	O
used	O
,	O
by	O
analogy	O
,	O
for	O
a	O
single	O
row	O
of	O
pixels	B-Algorithm
in	O
a	O
raster	B-Algorithm
graphics	I-Algorithm
image	O
.	O
</s>
<s>
Scan	B-Algorithm
lines	I-Algorithm
are	O
important	O
in	O
representations	O
of	O
image	O
data	O
,	O
because	O
many	O
image	O
file	O
formats	O
have	O
special	O
rules	O
for	O
data	O
at	O
the	O
end	O
of	O
a	O
scan	B-Algorithm
line	I-Algorithm
.	O
</s>
<s>
For	O
example	O
,	O
there	O
may	O
be	O
a	O
rule	O
that	O
each	O
scan	B-Algorithm
line	I-Algorithm
starts	O
on	O
a	O
particular	O
boundary	O
(	O
such	O
as	O
a	O
byte	O
or	O
word	O
;	O
see	O
for	O
example	O
BMP	B-Device
file	I-Device
format	I-Device
)	O
.	O
</s>
<s>
This	O
means	O
that	O
even	O
otherwise	O
compatible	O
raster	O
data	O
may	O
need	O
to	O
be	O
analyzed	O
at	O
the	O
level	O
of	O
scan	B-Algorithm
lines	I-Algorithm
in	O
order	O
to	O
convert	O
between	O
formats	O
.	O
</s>
