<s>
A	O
3D	B-Algorithm
display	I-Algorithm
is	O
a	O
display	B-Device
device	I-Device
capable	O
of	O
conveying	O
depth	O
to	O
the	O
viewer	O
.	O
</s>
<s>
Many	O
3D	B-Algorithm
displays	I-Algorithm
are	O
stereoscopic	B-Algorithm
displays	I-Algorithm
,	O
which	O
produce	O
a	O
basic	O
3D	O
effect	O
by	O
means	O
of	O
stereopsis	B-Algorithm
,	O
but	O
can	O
cause	O
eye	O
strain	O
and	O
visual	O
fatigue	O
.	O
</s>
<s>
Newer	O
3D	B-Algorithm
displays	I-Algorithm
such	O
as	O
holographic	B-Algorithm
and	O
light	B-Algorithm
field	I-Algorithm
displays	I-Algorithm
produce	O
a	O
more	O
realistic	O
3D	O
effect	O
by	O
combining	O
stereopsis	B-Algorithm
and	O
accurate	O
focal	B-Algorithm
length	I-Algorithm
for	O
the	O
displayed	O
content	O
.	O
</s>
<s>
Newer	O
3D	B-Algorithm
displays	I-Algorithm
in	O
this	O
manner	O
cause	O
less	O
visual	O
fatigue	O
than	O
classical	O
stereoscopic	B-Algorithm
displays	I-Algorithm
.	O
</s>
<s>
As	O
of	O
2021	O
,	O
the	O
most	O
common	O
type	O
of	O
3D	B-Algorithm
display	I-Algorithm
is	O
a	O
stereoscopic	B-Algorithm
display	I-Algorithm
,	O
which	O
is	O
the	O
type	O
of	O
display	O
used	O
in	O
almost	O
all	O
virtual	B-Application
reality	I-Application
equipment	O
.	O
</s>
<s>
3D	B-Algorithm
displays	I-Algorithm
can	O
be	O
near-eye	O
displays	O
like	O
in	O
VR	O
headsets	O
,	O
or	O
they	O
can	O
be	O
in	O
a	O
device	O
further	O
away	O
from	O
the	O
eyes	O
like	O
a	O
3D-enabled	O
mobile	O
device	O
or	O
3D	B-Algorithm
movie	I-Algorithm
theater	I-Algorithm
.	O
</s>
<s>
The	O
term	O
“	O
3D	B-Algorithm
display	I-Algorithm
”	O
can	O
also	O
be	O
used	O
to	O
refer	O
to	O
a	O
volumetric	O
display	O
which	O
may	O
generate	O
content	O
that	O
can	O
be	O
viewed	O
from	O
all	O
angles	O
.	O
</s>
<s>
The	O
first	O
3D	B-Algorithm
display	I-Algorithm
was	O
created	O
by	O
Sir	O
Charles	O
Wheatstone	O
in	O
1832	O
.	O
</s>
<s>
It	O
was	O
a	O
stereoscopic	B-Algorithm
display	I-Algorithm
that	O
had	O
rudimentary	O
ability	O
for	O
representing	O
depth	O
.	O
</s>
<s>
The	O
basic	O
technique	O
of	O
stereo	B-Algorithm
displays	I-Algorithm
is	O
to	O
present	O
offset	O
images	O
that	O
are	O
displayed	O
separately	O
to	O
the	O
left	O
and	O
right	O
eye	O
.	O
</s>
<s>
The	O
most	O
notable	O
difference	O
to	O
real	O
3D	B-Algorithm
displays	I-Algorithm
is	O
that	O
the	O
observer	O
's	O
head	O
and	O
eyes	O
movements	O
will	O
not	O
increase	O
information	O
about	O
the	O
3D	O
objects	O
being	O
displayed	O
.	O
</s>
<s>
For	O
example	O
,	O
holographic	B-Algorithm
displays	I-Algorithm
do	O
not	O
have	O
such	O
limitations	O
.	O
</s>
<s>
The	O
accurate	O
term	O
"	O
stereoscopic	B-Algorithm
"	O
is	O
more	O
cumbersome	O
than	O
the	O
common	O
misnomer	O
"	O
3D	O
"	O
,	O
which	O
has	O
been	O
entrenched	O
after	O
many	O
decades	O
of	O
unquestioned	O
misuse	O
.	O
</s>
<s>
Although	O
most	O
stereoscopic	B-Algorithm
displays	I-Algorithm
do	O
not	O
qualify	O
as	O
real	O
3D	B-Algorithm
displays	I-Algorithm
,	O
all	O
real	O
3D	B-Algorithm
displays	I-Algorithm
are	O
often	O
referred	O
to	O
as	O
also	O
stereoscopic	B-Algorithm
displays	I-Algorithm
because	O
they	O
meet	O
the	O
lower	O
criteria	O
of	O
being	O
stereoscopic	B-Algorithm
as	O
well	O
.	O
</s>
<s>
Based	O
on	O
the	O
principles	O
of	O
stereopsis	B-Algorithm
,	O
described	O
by	O
Sir	O
Charles	O
Wheatstone	O
in	O
the	O
1830s	O
,	O
stereoscopic	B-Algorithm
technology	O
provides	O
a	O
different	O
image	O
to	O
the	O
viewer	O
's	O
left	O
and	O
right	O
eyes	O
.	O
</s>
<s>
The	O
following	O
are	O
some	O
of	O
the	O
technical	O
details	O
and	O
methodologies	O
employed	O
in	O
some	O
of	O
the	O
more	O
notable	O
stereoscopic	B-Algorithm
systems	O
that	O
have	O
been	O
developed	O
.	O
</s>
<s>
Traditional	O
stereoscopic	B-Algorithm
photography	I-Algorithm
consists	O
of	O
creating	O
a	O
3D	O
illusion	O
starting	O
from	O
a	O
pair	O
of	O
2D	O
images	O
,	O
a	O
stereogram	B-Algorithm
.	O
</s>
<s>
The	O
easiest	O
way	O
to	O
enhance	O
depth	O
perception	O
in	O
the	O
brain	O
is	O
to	O
provide	O
the	O
eyes	O
of	O
the	O
viewer	O
with	O
two	O
different	O
images	O
,	O
representing	O
two	O
perspectives	B-Architecture
of	O
the	O
same	O
object	O
,	O
with	O
a	O
minor	O
deviation	O
exactly	O
equal	O
to	O
the	O
perspectives	B-Architecture
that	O
both	O
eyes	O
naturally	O
receive	O
in	O
binocular	B-Algorithm
vision	I-Algorithm
.	O
</s>
<s>
A	O
stereoscope	O
is	O
a	O
device	O
for	O
viewing	O
stereographic	B-Algorithm
cards	O
,	O
which	O
are	O
cards	O
that	O
contain	O
two	O
separate	O
images	O
that	O
are	O
printed	O
side	O
by	O
side	O
to	O
create	O
the	O
illusion	O
of	O
a	O
three-dimensional	O
image	O
.	O
</s>
<s>
Pairs	O
of	O
stereo	B-Algorithm
views	O
printed	O
on	O
a	O
transparent	O
base	O
are	O
viewed	O
by	O
transmitted	O
light	O
.	O
</s>
<s>
The	O
practice	O
of	O
viewing	O
film-based	O
stereoscopic	B-Algorithm
transparencies	O
dates	O
to	O
at	O
least	O
as	O
early	O
as	O
1931	O
,	O
when	O
Tru-Vue	O
began	O
to	O
market	O
sets	O
of	O
stereo	B-Algorithm
views	O
on	O
strips	O
of	O
35	O
mm	O
film	O
that	O
were	O
fed	O
through	O
a	O
hand-held	O
Bakelite	O
viewer	O
.	O
</s>
<s>
The	O
user	O
typically	O
wears	O
a	O
helmet	O
or	O
glasses	O
with	O
two	O
small	O
LCD	B-Device
or	O
OLED	B-Device
displays	I-Device
with	O
magnifying	O
lenses	O
,	O
one	O
for	O
each	O
eye	O
.	O
</s>
<s>
The	O
technology	O
can	O
be	O
used	O
to	O
show	O
stereo	B-Algorithm
films	I-Algorithm
,	O
images	O
or	O
games	O
.	O
</s>
<s>
Head-mounted	O
or	O
wearable	O
glasses	O
may	O
be	O
used	O
to	O
view	O
a	O
see-through	O
image	O
imposed	O
upon	O
the	O
real	O
world	O
view	O
,	O
creating	O
what	O
is	O
called	O
augmented	B-General_Concept
reality	I-General_Concept
.	O
</s>
<s>
A	O
recent	O
development	O
in	O
holographic-waveguide	O
or	O
"	O
waveguide-based	O
optics	O
"	O
allows	O
a	O
stereoscopic	B-Algorithm
images	I-Algorithm
to	O
be	O
superimposed	O
on	O
real	O
world	O
without	O
the	O
uses	O
of	O
bulky	O
reflective	O
mirror	O
.	O
</s>
<s>
Head-mounted	O
projection	O
displays	O
(	O
HMPD	O
)	O
is	O
similar	O
to	O
head-mounted	O
displays	O
but	O
with	O
images	O
projected	O
to	O
and	O
displayed	O
on	O
a	O
retroreflective	O
screen	O
,	O
The	O
advantage	O
of	O
this	O
technology	O
over	O
head-mounted	O
display	O
is	O
that	O
the	O
focusing	O
and	O
vergence	B-Algorithm
issues	O
did	O
n't	O
require	O
fixing	O
with	O
corrective	O
eye	O
lenses	O
.	O
</s>
<s>
For	O
image	O
generation	O
,	O
Pico-projectors	B-General_Concept
are	O
used	O
instead	O
of	O
LCD	B-Device
or	O
OLED	B-Device
screens	I-Device
.	O
</s>
<s>
Process	O
reconfigures	O
the	O
typical	O
anaglyph	O
image	O
to	O
have	O
less	O
parallax	B-Device
.	O
</s>
<s>
An	O
alternative	O
to	O
the	O
usual	O
red	O
and	O
cyan	O
filter	O
system	O
of	O
anaglyph	O
is	O
ColorCode	B-Algorithm
3-D	I-Algorithm
,	O
a	O
patented	O
anaglyph	O
system	O
which	O
was	O
invented	O
in	O
order	O
to	O
present	O
an	O
anaglyph	O
image	O
in	O
conjunction	O
with	O
the	O
NTSC	O
television	O
standard	O
,	O
in	O
which	O
the	O
red	O
channel	O
is	O
often	O
compromised	O
.	O
</s>
<s>
To	O
present	O
a	O
stereoscopic	B-Algorithm
picture	I-Algorithm
,	O
two	O
images	O
are	O
projected	O
superimposed	O
onto	O
the	O
same	O
screen	O
through	O
different	O
polarizing	O
filters	O
.	O
</s>
<s>
This	O
is	O
used	O
to	O
produce	O
a	O
three-dimensional	O
effect	O
by	O
projecting	O
the	O
same	O
scene	O
into	O
both	O
eyes	O
,	O
but	O
depicted	O
from	O
slightly	O
different	O
perspectives	B-Architecture
.	O
</s>
<s>
So	O
an	O
expensive	O
silver	O
screen	O
or	O
aluminized	B-General_Concept
screen	I-General_Concept
with	O
negligible	O
polarization	O
loss	O
has	O
to	O
be	O
used	O
.	O
</s>
<s>
This	O
was	O
the	O
basis	O
of	O
the	O
Teleview	B-Algorithm
system	O
which	O
was	O
used	O
briefly	O
in	O
1922	O
.	O
</s>
<s>
A	O
variation	O
on	O
the	O
eclipse	O
method	O
is	O
used	O
in	O
LCD	B-Algorithm
shutter	I-Algorithm
glasses	I-Algorithm
.	O
</s>
<s>
Glasses	O
containing	O
liquid	B-Device
crystal	I-Device
that	O
will	O
let	O
light	O
through	O
in	O
synchronization	O
with	O
the	O
images	O
on	O
the	O
cinema	O
,	O
television	O
or	O
computer	O
screen	O
,	O
using	O
the	O
concept	O
of	O
alternate-frame	B-Algorithm
sequencing	I-Algorithm
.	O
</s>
<s>
This	O
is	O
the	O
method	O
used	O
by	O
nVidia	O
,	O
XpanD	B-Algorithm
3D	I-Algorithm
,	O
and	O
earlier	O
IMAX	O
systems	O
.	O
</s>
<s>
Liquid	B-Device
crystal	I-Device
light	O
valves	O
work	O
by	O
rotating	O
light	O
between	O
two	O
polarizing	O
filters	O
.	O
</s>
<s>
Due	O
to	O
these	O
internal	O
polarizers	O
,	O
LCD	B-Device
shutter-glasses	O
darken	O
the	O
display	O
image	O
of	O
any	O
LCD	B-Device
,	O
plasma	O
,	O
or	O
projector	O
image	O
source	O
,	O
which	O
has	O
the	O
result	O
that	O
images	O
appear	O
dimmer	O
and	O
contrast	O
is	O
lower	O
than	O
for	O
normal	O
non-3D	O
viewing	O
.	O
</s>
<s>
This	O
is	O
not	O
necessarily	O
a	O
usage	O
problem	O
;	O
for	O
some	O
types	O
of	O
displays	O
which	O
are	O
already	O
very	O
bright	O
with	O
poor	O
grayish	O
black	O
levels	O
,	O
LCD	B-Algorithm
shutter	I-Algorithm
glasses	I-Algorithm
may	O
actually	O
improve	O
the	O
image	O
quality	O
.	O
</s>
<s>
Dolby	B-Algorithm
3D	I-Algorithm
uses	O
specific	O
wavelengths	O
of	O
red	O
,	O
green	O
,	O
and	O
blue	O
for	O
the	O
right	O
eye	O
,	O
and	O
different	O
wavelengths	O
of	O
red	O
,	O
green	O
,	O
and	O
blue	O
for	O
the	O
left	O
eye	O
.	O
</s>
<s>
Eyeglasses	O
which	O
filter	O
out	O
the	O
very	O
specific	O
wavelengths	O
allow	O
the	O
wearer	O
to	O
see	O
a	O
3D	B-Algorithm
image	I-Algorithm
.	O
</s>
<s>
This	O
technology	O
eliminates	O
the	O
expensive	O
silver	O
screens	O
required	O
for	O
polarized	O
systems	O
such	O
as	O
RealD	O
,	O
which	O
is	O
the	O
most	O
common	O
3D	B-Algorithm
display	I-Algorithm
system	O
in	O
theaters	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
passive	O
stereoscopic	B-Algorithm
3D	I-Algorithm
system	O
,	O
Omega	O
Optical	O
has	O
produced	O
enhanced	O
anaglyph	O
3D	O
glasses	O
.	O
</s>
<s>
In	O
this	O
method	O
,	O
glasses	O
are	O
not	O
necessary	O
to	O
see	O
the	O
stereoscopic	B-Algorithm
image	I-Algorithm
.	O
</s>
<s>
Lenticular	O
lens	O
and	O
parallax	B-Algorithm
barrier	I-Algorithm
technologies	O
involve	O
imposing	O
two	O
(	O
or	O
more	O
)	O
images	O
on	O
the	O
same	O
sheet	O
,	O
in	O
narrow	O
,	O
alternating	O
strips	O
,	O
and	O
using	O
a	O
screen	O
that	O
either	O
blocks	O
one	O
of	O
the	O
two	O
images	O
 '	O
strips	O
(	O
in	O
the	O
case	O
of	O
parallax	B-Algorithm
barriers	I-Algorithm
)	O
or	O
uses	O
equally	O
narrow	O
lenses	O
to	O
bend	O
the	O
strips	O
of	O
image	O
and	O
make	O
it	O
appear	O
to	O
fill	O
the	O
entire	O
image	O
(	O
in	O
the	O
case	O
of	O
lenticular	O
prints	O
)	O
.	O
</s>
<s>
To	O
produce	O
the	O
stereoscopic	B-Algorithm
effect	O
,	O
the	O
person	O
must	O
be	O
positioned	O
so	O
that	O
one	O
eye	O
sees	O
one	O
of	O
the	O
two	O
images	O
and	O
the	O
other	O
sees	O
the	O
other	O
.	O
</s>
<s>
The	O
optical	O
principles	O
of	O
multiview	O
auto-stereoscopy	O
have	O
been	O
known	O
for	O
over	O
a	O
century	O
.	O
</s>
<s>
In	O
order	O
to	O
see	O
the	O
stereoscopic	B-Algorithm
image	I-Algorithm
,	O
the	O
viewer	O
must	O
sit	O
within	O
a	O
very	O
narrow	O
angle	O
that	O
is	O
nearly	O
perpendicular	O
to	O
the	O
screen	O
,	O
limiting	O
the	O
size	O
of	O
the	O
audience	O
.	O
</s>
<s>
Though	O
its	O
use	O
in	O
theatrical	O
presentations	O
has	O
been	O
rather	O
limited	O
,	O
lenticular	O
has	O
been	O
widely	O
used	O
for	O
a	O
variety	O
of	O
novelty	O
items	O
and	O
has	O
even	O
been	O
used	O
in	O
amateur	O
3D	B-Algorithm
photography	I-Algorithm
.	O
</s>
<s>
Recent	O
use	O
includes	O
the	O
Fujifilm	B-Algorithm
FinePix	I-Algorithm
Real	I-Algorithm
3D	I-Algorithm
with	O
an	O
autostereoscopic	B-Algorithm
display	I-Algorithm
that	O
was	O
released	O
in	O
2009	O
.	O
</s>
<s>
Other	O
examples	O
for	O
this	O
technology	O
include	O
autostereoscopic	B-Algorithm
LCD	B-Device
displays	I-Device
on	O
monitors	O
,	O
notebooks	O
,	O
TVs	O
,	O
mobile	O
phones	O
and	O
gaming	O
devices	O
,	O
such	O
as	O
the	O
Nintendo	B-Operating_System
3DS	I-Operating_System
.	O
</s>
<s>
The	O
Pulfrich	B-Algorithm
effect	I-Algorithm
is	O
a	O
psychophysical	O
percept	B-General_Concept
wherein	O
lateral	O
motion	O
of	O
an	O
object	O
in	O
the	O
field	O
of	O
view	O
is	O
interpreted	O
by	O
the	O
visual	O
cortex	O
as	O
having	O
a	O
depth	O
component	O
,	O
due	O
to	O
a	O
relative	O
difference	O
in	O
signal	O
timings	O
between	O
the	O
two	O
eyes	O
.	O
</s>
<s>
Prismatic	O
glasses	O
make	O
cross-viewing	O
easier	O
as	O
well	O
as	O
over/under	O
-viewing	O
possible	O
,	O
examples	O
include	O
the	O
KMQ	B-Algorithm
viewer	I-Algorithm
.	O
</s>
<s>
Such	O
displays	O
use	O
voxels	B-Algorithm
instead	O
of	O
pixels	B-Algorithm
.	O
</s>
<s>
A	O
light	B-Algorithm
field	I-Algorithm
display	I-Algorithm
tries	O
to	O
recreate	O
a	O
"	O
light	O
field	O
"	O
on	O
the	O
surface	O
of	O
the	O
display	O
.	O
</s>
<s>
In	O
contrast	O
to	O
a	O
2D	O
display	O
which	O
shows	O
a	O
distinct	O
color	O
on	O
each	O
pixel	B-Algorithm
,	O
a	O
light	B-Algorithm
field	I-Algorithm
display	I-Algorithm
shows	O
a	O
distinct	O
color	O
on	O
each	O
pixel	B-Algorithm
for	O
each	O
direction	O
that	O
the	O
light	O
ray	O
emits	O
to	O
.	O
</s>
<s>
This	O
way	O
,	O
eyes	O
from	O
different	O
positions	O
will	O
see	O
different	O
pictures	O
on	O
the	O
display	O
,	O
creating	O
parallax	B-Device
and	O
thus	O
creating	O
a	O
sense	O
of	O
3D	O
.	O
</s>
<s>
A	O
light	B-Algorithm
field	I-Algorithm
display	I-Algorithm
is	O
like	O
a	O
glass	O
window	O
,	O
people	O
see	O
3D	O
objects	O
behind	O
the	O
glass	O
,	O
despite	O
that	O
all	O
light	O
rays	O
they	O
see	O
come	O
from	O
(	O
through	O
)	O
the	O
glass	O
.	O
</s>
<s>
Holographic	B-Algorithm
display	I-Algorithm
is	O
a	O
display	B-Device
technology	I-Device
that	O
has	O
the	O
ability	O
to	O
provide	O
all	O
four	O
eye	O
mechanisms	O
:	O
binocular	O
disparity	O
,	O
motion	O
parallax	B-Device
,	O
accommodation	O
and	O
convergence	O
.	O
</s>
<s>
In	O
2013	O
,	O
a	O
Silicon	O
valley	O
Company	O
LEIA	B-Algorithm
Inc	I-Algorithm
started	O
manufacturing	O
holographic	B-Algorithm
displays	I-Algorithm
well	O
suited	O
for	O
mobile	O
devices	O
(	O
watches	O
,	O
smartphones	O
or	O
tablets	O
)	O
using	O
a	O
multi-directional	O
backlight	O
and	O
allowing	O
a	O
wide	O
full-parallax	O
angle	O
view	O
to	O
see	O
3D	O
content	O
without	O
the	O
need	O
of	O
glasses	O
.	O
</s>
<s>
Their	O
first	O
product	O
was	O
part	O
of	O
a	O
mobile	O
phone	O
(	O
Red	B-Application
Hydrogen	I-Application
One	I-Application
)	O
and	O
later	O
on	O
in	O
their	O
own	O
Android	O
tablet	O
.	O
</s>
<s>
Integral	B-Algorithm
imaging	I-Algorithm
is	O
an	O
autostereoscopic	B-Algorithm
or	O
multiscopic	B-General_Concept
3D	B-Algorithm
display	I-Algorithm
,	O
meaning	O
that	O
it	O
displays	O
a	O
3D	B-Algorithm
image	I-Algorithm
without	O
the	O
use	O
of	O
special	O
glasses	O
on	O
the	O
part	O
of	O
the	O
viewer	O
.	O
</s>
<s>
Thus	O
rather	O
than	O
displaying	O
a	O
2D	O
image	O
that	O
looks	O
the	O
same	O
from	O
every	O
direction	O
,	O
it	O
reproduces	O
a	O
3D	O
light	O
field	O
,	O
creating	O
stereo	B-Algorithm
images	O
that	O
exhibit	O
parallax	B-Device
when	O
the	O
viewer	O
moves	O
.	O
</s>
<s>
A	O
new	O
display	B-Device
technology	I-Device
called	O
"	O
compressive	O
light	O
field	O
"	O
is	O
being	O
developed	O
.	O
</s>
<s>
These	O
prototype	O
displays	O
use	O
layered	O
LCD	B-Device
panels	I-Device
and	O
compression	O
algorithms	O
at	O
the	O
time	O
of	O
display	O
.	O
</s>
<s>
devices	O
that	O
are	O
driven	O
by	O
algorithms	O
such	O
as	O
computed	O
tomography	O
and	O
Non-negative	O
matrix	O
factorization	O
and	O
non-negative	O
tensor	B-Device
factorization	O
.	O
</s>
<s>
Each	O
of	O
these	O
display	B-Device
technologies	I-Device
can	O
be	O
seen	O
to	O
have	O
limitations	O
,	O
whether	O
the	O
location	O
of	O
the	O
viewer	O
,	O
cumbersome	O
or	O
unsightly	O
equipment	O
or	O
great	O
cost	O
.	O
</s>
<s>
The	O
display	O
of	O
artifact-free	O
3D	B-Algorithm
images	I-Algorithm
remains	O
difficult	O
.	O
</s>
