<s>
A	O
digital	B-Algorithm
image	I-Algorithm
is	O
an	O
image	O
composed	O
of	O
picture	B-Algorithm
elements	I-Algorithm
,	O
also	O
known	O
as	O
pixels	B-Algorithm
,	O
each	O
with	O
finite	O
,	O
discrete	O
quantities	O
of	O
numeric	O
representation	O
for	O
its	O
intensity	B-Application
or	O
gray	O
level	O
that	O
is	O
an	O
output	O
from	O
its	O
two-dimensional	O
functions	O
fed	O
as	O
input	O
by	O
its	O
spatial	O
coordinates	O
denoted	O
with	O
x	O
,	O
y	O
on	O
the	O
x-axis	O
and	O
y-axis	O
,	O
respectively	O
.	O
</s>
<s>
Depending	O
on	O
whether	O
the	O
image	B-Algorithm
resolution	I-Algorithm
is	O
fixed	O
,	O
it	O
may	O
be	O
of	O
vector	O
or	O
raster	B-Algorithm
type	O
.	O
</s>
<s>
Raster	B-Algorithm
images	I-Algorithm
have	O
a	O
finite	O
set	O
of	O
digital	B-General_Concept
values	O
,	O
called	O
picture	B-Algorithm
elements	I-Algorithm
or	O
pixels	B-Algorithm
.	O
</s>
<s>
The	O
digital	B-Algorithm
image	I-Algorithm
contains	O
a	O
fixed	O
number	O
of	O
rows	O
and	O
columns	O
of	O
pixels	B-Algorithm
.	O
</s>
<s>
Pixels	B-Algorithm
are	O
the	O
smallest	O
individual	O
element	O
in	O
an	O
image	O
,	O
holding	O
quantized	O
values	O
that	O
represent	O
the	O
brightness	O
of	O
a	O
given	O
color	O
at	O
any	O
specific	O
point	O
.	O
</s>
<s>
Typically	O
,	O
the	O
pixels	B-Algorithm
are	O
stored	O
in	O
computer	B-General_Concept
memory	I-General_Concept
as	O
a	O
raster	B-Algorithm
image	I-Algorithm
or	O
raster	B-Algorithm
map	O
,	O
a	O
two-dimensional	O
array	O
of	O
small	O
integers	O
.	O
</s>
<s>
These	O
values	O
are	O
often	O
transmitted	O
or	O
stored	O
in	O
a	O
compressed	B-General_Concept
form	O
.	O
</s>
<s>
Raster	B-Algorithm
images	I-Algorithm
can	O
be	O
created	B-Algorithm
by	O
a	O
variety	O
of	O
input	O
devices	O
and	O
techniques	O
,	O
such	O
as	O
digital	B-Device
cameras	I-Device
,	O
scanners	O
,	O
coordinate-measuring	O
machines	O
,	O
seismographic	O
profiling	O
,	O
airborne	O
radar	O
,	O
and	O
more	O
.	O
</s>
<s>
The	O
field	O
of	O
digital	B-Algorithm
image	I-Algorithm
processing	I-Algorithm
is	O
the	O
study	O
of	O
algorithms	O
for	O
their	O
transformation	O
.	O
</s>
<s>
Most	O
users	O
come	O
into	O
contact	O
with	O
raster	B-Algorithm
images	I-Algorithm
through	O
digital	B-Device
cameras	I-Device
,	O
which	O
use	O
any	O
of	O
several	O
image	O
file	O
formats	O
.	O
</s>
<s>
Some	O
digital	B-Device
cameras	I-Device
give	O
access	O
to	O
almost	O
all	O
the	O
data	O
captured	O
by	O
the	O
camera	O
,	O
using	O
a	O
raw	B-Application
image	I-Application
format	I-Application
.	O
</s>
<s>
The	O
Universal	O
Photographic	O
Imaging	O
Guidelines	O
(	O
UPDIG	O
)	O
suggests	O
these	O
formats	O
be	O
used	O
when	O
possible	O
since	O
raw	B-Application
files	I-Application
produce	O
the	O
best	O
quality	O
images	O
.	O
</s>
<s>
Their	O
use	O
is	O
inhibited	O
by	O
the	O
prevalence	O
of	O
proprietary	O
information	O
(	O
trade	O
secrets	O
)	O
for	O
some	O
camera	O
makers	O
,	O
but	O
there	O
have	O
been	O
initiatives	O
such	O
as	O
OpenRAW	B-Application
to	O
influence	O
manufacturers	O
to	O
release	O
these	O
records	O
publicly	O
.	O
</s>
<s>
An	O
alternative	O
may	O
be	O
Digital	B-Application
Negative	I-Application
(	O
DNG	O
)	O
,	O
a	O
proprietary	O
Adobe	O
product	O
described	O
as	O
"	O
the	O
public	O
,	O
archival	O
format	O
for	O
digital	B-Device
camera	I-Device
raw	O
data	O
"	O
.	O
</s>
<s>
Often	O
,	O
both	O
raster	B-Algorithm
and	O
vector	O
elements	O
will	O
be	O
combined	O
in	O
one	O
image	O
;	O
for	O
example	O
,	O
in	O
the	O
case	O
of	O
a	O
billboard	O
with	O
text	O
(	O
vector	O
)	O
and	O
photographs	O
(	O
raster	B-Algorithm
)	O
.	O
</s>
<s>
Example	O
of	O
vector	O
file	O
types	O
are	O
EPS	B-Language
,	O
PDF	B-Application
,	O
and	O
AI	O
.	O
</s>
<s>
Web	B-Application
browsers	I-Application
can	O
display	O
standard	O
internet	O
image	O
formats	O
including	O
JPEG	O
,	O
GIF	O
and	O
PNG	O
.	O
</s>
<s>
Some	O
can	O
show	O
SVG	B-Application
format	I-Application
which	O
is	O
a	O
standard	O
W3C	O
format	O
.	O
</s>
<s>
Some	O
scientific	O
images	O
can	O
be	O
very	O
large	O
(	O
for	O
instance	O
,	O
the	O
46	O
gigapixel	B-Algorithm
size	O
image	O
of	O
the	O
Milky	O
Way	O
,	O
about	O
194	O
Gb	O
in	O
size	O
)	O
.	O
</s>
<s>
Early	O
digital	B-General_Concept
fax	O
machines	O
such	O
as	O
the	O
Bartlane	O
cable	O
picture	O
transmission	O
system	O
preceded	O
digital	B-Device
cameras	I-Device
and	O
computers	O
by	O
decades	O
.	O
</s>
<s>
The	O
first	O
picture	O
to	O
be	O
scanned	O
,	O
stored	O
,	O
and	O
recreated	O
in	O
digital	B-General_Concept
pixels	B-Algorithm
was	O
displayed	O
on	O
the	O
Standards	B-Device
Eastern	I-Device
Automatic	I-Device
Computer	I-Device
(	O
SEAC	B-Device
)	O
at	O
NIST	O
.	O
</s>
<s>
The	O
advancement	O
of	O
digital	B-General_Concept
imagery	O
continued	O
in	O
the	O
early	O
1960s	O
,	O
alongside	O
development	O
of	O
the	O
space	O
program	O
and	O
in	O
medical	O
research	O
.	O
</s>
<s>
Projects	O
at	O
the	O
Jet	O
Propulsion	O
Laboratory	O
,	O
MIT	O
,	O
Bell	O
Labs	O
and	O
the	O
University	O
of	O
Maryland	O
,	O
among	O
others	O
,	O
used	O
digital	B-Algorithm
images	I-Algorithm
to	O
advance	O
satellite	O
imagery	O
,	O
wirephoto	O
standards	O
conversion	O
,	O
medical	O
imaging	O
,	O
videophone	B-Application
technology	O
,	O
character	B-Application
recognition	I-Application
,	O
and	O
photo	O
enhancement	O
.	O
</s>
<s>
Rapid	O
advances	O
in	O
digital	B-Algorithm
imaging	I-Algorithm
began	O
with	O
the	O
introduction	O
of	O
MOS	O
integrated	O
circuits	O
in	O
the	O
1960s	O
and	O
microprocessors	B-Architecture
in	O
the	O
early	O
1970s	O
,	O
alongside	O
progress	O
in	O
related	O
computer	B-General_Concept
memory	I-General_Concept
storage	O
,	O
display	B-Device
technologies	I-Device
,	O
and	O
data	B-General_Concept
compression	I-General_Concept
algorithms	I-General_Concept
.	O
</s>
<s>
The	O
invention	O
of	O
computerized	O
axial	O
tomography	O
(	O
CAT	O
scanning	O
)	O
,	O
using	O
x-rays	B-Library
to	O
produce	O
a	O
digital	B-Algorithm
image	I-Algorithm
of	O
a	O
"	O
slice	O
"	O
through	O
a	O
three-dimensional	O
object	O
,	O
was	O
of	O
great	O
importance	O
to	O
medical	O
diagnostics	O
.	O
</s>
<s>
As	O
well	O
as	O
origination	O
of	O
digital	B-Algorithm
images	I-Algorithm
,	O
digitization	O
of	O
analog	O
images	O
allowed	O
the	O
enhancement	O
and	O
restoration	O
of	O
archaeological	O
artifacts	O
and	O
began	O
to	O
be	O
used	O
in	O
fields	O
as	O
diverse	O
as	O
nuclear	O
medicine	O
,	O
astronomy	O
,	O
law	O
enforcement	O
,	O
defence	O
and	O
industry	O
.	O
</s>
<s>
Advances	O
in	O
microprocessor	B-Architecture
technology	O
paved	O
the	O
way	O
for	O
the	O
development	O
and	O
marketing	O
of	O
charge-coupled	B-Algorithm
devices	I-Algorithm
(	O
CCDs	O
)	O
for	O
use	O
in	O
a	O
wide	O
range	O
of	O
image	O
capture	O
devices	O
and	O
gradually	O
displaced	O
the	O
use	O
of	O
analog	O
film	O
and	O
tape	O
in	O
photography	O
and	O
videography	O
towards	O
the	O
end	O
of	O
the	O
20th	O
century	O
.	O
</s>
<s>
The	O
computing	O
power	O
necessary	O
to	O
process	O
digital	B-Algorithm
image	I-Algorithm
capture	O
also	O
allowed	O
computer-generated	O
digital	B-Algorithm
images	I-Algorithm
to	O
achieve	O
a	O
level	O
of	O
refinement	O
close	O
to	O
photorealism	B-Application
.	O
</s>
<s>
As	O
it	O
was	O
fairly	O
straightforward	O
to	O
fabricate	B-Architecture
a	O
series	O
of	O
MOS	O
capacitors	O
in	O
a	O
row	O
,	O
they	O
connected	O
a	O
suitable	O
voltage	O
to	O
them	O
so	O
that	O
the	O
charge	O
could	O
be	O
stepped	O
along	O
from	O
one	O
to	O
the	O
next	O
.	O
</s>
<s>
The	O
CCD	O
is	O
a	O
semiconductor	O
circuit	O
that	O
was	O
later	O
used	O
in	O
the	O
first	O
digital	B-General_Concept
video	O
cameras	O
for	O
television	O
broadcasting	O
.	O
</s>
<s>
Early	O
CCD	B-Algorithm
sensors	I-Algorithm
suffered	O
from	O
shutter	O
lag	O
.	O
</s>
<s>
In	O
1987	O
,	O
the	O
PPD	O
began	O
to	O
be	O
incorporated	O
into	O
most	O
CCD	O
devices	O
,	O
becoming	O
a	O
fixture	O
in	O
consumer	O
electronic	O
video	O
cameras	O
and	O
then	O
digital	B-Device
still	I-Device
cameras	I-Device
.	O
</s>
<s>
Since	O
then	O
,	O
the	O
PPD	O
has	O
been	O
used	O
in	O
nearly	O
all	O
CCD	B-Algorithm
sensors	I-Algorithm
and	O
then	O
CMOS	B-Architecture
sensors	I-Architecture
.	O
</s>
<s>
The	O
NMOS	B-Algorithm
active-pixel	B-Architecture
sensor	I-Architecture
(	O
APS	O
)	O
was	O
invented	O
by	O
Olympus	O
in	O
Japan	O
during	O
the	O
mid-1980s	O
.	O
</s>
<s>
This	O
was	O
enabled	O
by	O
advances	O
in	O
MOS	O
semiconductor	B-Architecture
device	I-Architecture
fabrication	I-Architecture
,	O
with	O
MOSFET	O
scaling	O
reaching	O
smaller	O
micron	B-Algorithm
and	I-Algorithm
then	I-Algorithm
sub-micron	I-Algorithm
levels	O
.	O
</s>
<s>
The	O
NMOS	B-Algorithm
APS	O
was	O
fabricated	O
by	O
Tsutomu	O
Nakamura	O
's	O
team	O
at	O
Olympus	O
in	O
1985	O
.	O
</s>
<s>
The	O
CMOS	B-Device
active-pixel	B-Architecture
sensor	I-Architecture
(	O
CMOS	B-Architecture
sensor	I-Architecture
)	O
was	O
later	O
developed	O
by	O
Eric	O
Fossum	O
's	O
team	O
at	O
the	O
NASA	O
Jet	O
Propulsion	O
Laboratory	O
in	O
1993	O
.	O
</s>
<s>
By	O
2007	O
,	O
sales	O
of	O
CMOS	B-Architecture
sensors	I-Architecture
had	O
surpassed	O
CCD	B-Algorithm
sensors	I-Algorithm
.	O
</s>
<s>
An	O
important	O
development	O
in	O
digital	B-Algorithm
image	I-Algorithm
compression	O
technology	O
was	O
the	O
discrete	B-General_Concept
cosine	I-General_Concept
transform	I-General_Concept
(	O
DCT	B-General_Concept
)	O
,	O
a	O
lossy	B-Algorithm
compression	I-Algorithm
technique	O
first	O
proposed	O
by	O
Nasir	O
Ahmed	O
in	O
1972	O
.	O
</s>
<s>
DCT	B-General_Concept
compression	O
is	O
used	O
in	O
JPEG	O
,	O
which	O
was	O
introduced	O
by	O
the	O
Joint	O
Photographic	O
Experts	O
Group	O
in	O
1992	O
.	O
</s>
<s>
In	O
digital	B-Algorithm
imaging	I-Algorithm
,	O
a	O
mosaic	O
is	O
a	O
combination	O
of	O
non-overlapping	O
images	O
,	O
arranged	O
in	O
some	O
tessellation	B-Algorithm
.	O
</s>
<s>
Gigapixel	B-Algorithm
images	I-Algorithm
are	O
an	O
example	O
of	O
such	O
digital	B-Algorithm
image	I-Algorithm
mosaics	O
.	O
</s>
<s>
Interactive	O
viewing	O
is	O
provided	O
by	O
virtual-reality	B-Application
photography	I-Application
.	O
</s>
