<s>
Random-dot	B-Algorithm
stereogram	I-Algorithm
(	O
RDS	O
)	O
is	O
stereo	O
pair	O
of	O
images	O
of	O
random	O
dots	O
which	O
,	O
when	O
viewed	O
with	O
the	O
aid	O
of	O
a	O
stereoscope	B-Algorithm
,	O
or	O
with	O
the	O
eyes	O
focused	O
on	O
a	O
point	O
in	O
front	O
of	O
or	O
behind	O
the	O
images	O
,	O
produces	O
a	O
sensation	O
of	O
depth	O
,	O
with	O
objects	O
appearing	O
to	O
be	O
in	O
front	O
of	O
or	O
behind	O
the	O
display	O
level	O
.	O
</s>
<s>
The	O
random-dot	B-Algorithm
stereogram	I-Algorithm
technique	O
,	O
known	O
since	O
1919	O
,	O
was	O
elaborated	O
on	O
by	O
Béla	O
Julesz	O
,	O
described	O
in	O
his	O
1971	O
book	O
,	O
Foundations	O
of	O
Cyclopean	O
Perception	O
.	O
</s>
<s>
Later	O
concepts	O
,	O
involving	O
single	O
images	O
,	O
not	O
necessarily	O
consisting	O
of	O
random	O
dots	O
,	O
and	O
more	O
well-known	O
to	O
the	O
general	O
public	O
,	O
are	O
autostereograms	B-Algorithm
.	O
</s>
<s>
In	O
1840	O
,	O
Sir	O
Charles	O
Wheatstone	O
developed	O
the	O
stereoscope	B-Algorithm
.	O
</s>
<s>
Julesz	O
noticed	O
that	O
two	O
identical	O
random	O
images	O
when	O
viewed	O
through	O
a	O
stereoscope	B-Algorithm
,	O
appeared	O
as	O
if	O
they	O
were	O
projected	O
onto	O
a	O
uniform	O
flat	O
surface	O
.	O
</s>
<s>
When	O
he	O
viewed	O
this	O
pair	O
through	O
the	O
stereoscope	B-Algorithm
,	O
the	O
square	O
appeared	O
to	O
rise	O
out	O
from	O
the	O
page	O
.	O
</s>
<s>
The	O
random	B-Algorithm
dot	I-Algorithm
stereogram	I-Algorithm
provided	O
insight	O
on	O
how	O
stereo	B-Algorithm
vision	I-Algorithm
is	O
processed	O
by	O
the	O
human	O
brain	O
.	O
</s>
<s>
According	O
to	O
Ralph	O
Siegel	O
,	O
Julesz	O
had	O
"	O
unambiguously	O
demonstrated	O
that	O
stereoscopic	B-Algorithm
depth	O
could	O
be	O
computed	O
in	O
the	O
absence	O
of	O
any	O
identifiable	O
objects	O
,	O
in	O
the	O
absence	O
of	O
any	O
perspective	O
,	O
in	O
the	O
absence	O
of	O
any	O
cues	O
available	O
to	O
either	O
eye	O
alone.	O
"	O
</s>
<s>
About	O
5%	O
of	O
people	O
cannot	O
see	O
the	O
depth	O
in	O
random-dot	B-Algorithm
stereograms	I-Algorithm
because	O
of	O
various	O
disorders	O
of	O
binocular	B-Algorithm
vision	I-Algorithm
.	O
</s>
<s>
The	O
randot	O
stereotest	O
is	O
a	O
vectograph	B-Algorithm
random	O
dot	O
stereotest	O
.	O
</s>
<s>
The	O
TNO	O
random	O
dot	O
stereotest	O
(	O
short	O
:	O
TNO	O
stereo	O
test	O
or	O
TNO	O
test	O
)	O
is	O
similar	O
to	O
the	O
randot	O
stereotest	O
but	O
is	O
an	O
anaglyph	B-Algorithm
in	O
place	O
of	O
a	O
vectograph	B-Algorithm
;	O
that	O
is	O
,	O
the	O
patient	O
wears	O
red-green	O
glasses	O
(	O
in	O
place	O
of	O
the	O
polarizing	O
glasses	O
used	O
in	O
the	O
randot	O
stereotest	O
)	O
.	O
</s>
<s>
The	O
name	O
random	B-Algorithm
dot	I-Algorithm
stereogram	I-Algorithm
specifically	O
refers	O
to	O
pairs	O
of	O
images	O
based	O
on	O
random	O
dots	O
.	O
</s>
<s>
Additional	O
work	O
by	O
Christopher	O
Tyler	O
and	O
Maureen	O
Clarke	O
led	O
to	O
their	O
inventing	O
single	O
images	O
yielding	O
depth	O
without	O
a	O
stereoscope	B-Algorithm
.	O
</s>
<s>
These	O
are	O
known	O
as	O
Single	O
Image	O
Random	B-Algorithm
Dot	I-Algorithm
Stereograms	I-Algorithm
(	O
SIRDS	B-Algorithm
)	O
,	O
or	O
Random	O
Dot	O
Autostereograms	B-Algorithm
.	O
</s>
<s>
Replacing	O
the	O
random	O
dot	O
base	O
pattern	O
with	O
an	O
image	O
or	O
texture	O
gives	O
the	O
form	O
that	O
made	O
the	O
Single	B-Algorithm
Image	I-Algorithm
Stereogram	I-Algorithm
known	O
to	O
the	O
general	O
public	O
,	O
through	O
the	O
Magic	B-General_Concept
Eye	I-General_Concept
series	O
of	O
books	O
.	O
</s>
<s>
Dynamic	O
random-dot	B-Algorithm
stereograms	I-Algorithm
consist	O
of	O
a	O
moving	O
stereoscopic	B-Algorithm
(	O
cyclopean	O
)	O
form	O
made	O
of	O
moving	O
random	O
dots	O
,	O
camouflaged	O
by	O
further	O
random	O
dots	O
.	O
</s>
<s>
When	O
presented	O
with	O
a	O
dynamic	O
random	B-Algorithm
dot	I-Algorithm
stereogram	I-Algorithm
with	O
stereoscopic	B-Algorithm
(	O
cyclopean	O
)	O
motion	O
stimuli	O
,	O
stereoscopic	B-Algorithm
motion	O
is	O
perceived	O
by	O
persons	O
with	O
normal	O
binocular	B-Algorithm
vision	I-Algorithm
and	O
more	O
generally	O
by	O
those	O
who	O
have	O
sufficient	O
binocular	B-Algorithm
vision	I-Algorithm
for	O
the	O
task	O
.	O
</s>
<s>
Dynamic	O
random-dot	B-Algorithm
stereograms	I-Algorithm
containing	O
binocular	O
motion	O
stimuli	O
can	O
be	O
designed	O
to	O
test	O
whether	O
someone	O
has	O
at	O
least	O
rudimentary	O
stereopsis	B-Algorithm
.	O
</s>
<s>
One	O
study	O
found	O
that	O
in	O
strabismic	O
patients	O
a	O
dynamic	O
random	B-Algorithm
dot	I-Algorithm
stereogram	I-Algorithm
yielded	O
a	O
significantly	O
higher	O
rate	O
detection	O
rate	O
for	O
stereopsis	B-Algorithm
than	O
the	O
Titmus	O
fly	O
stereotest	O
.	O
</s>
<s>
The	O
process	O
used	O
to	O
develop	O
the	O
first	O
random-dot	B-Algorithm
stereogram	I-Algorithm
is	O
illustrated	O
below	O
.	O
</s>
<s>
To	O
view	O
the	O
stereogram	O
,	O
use	O
a	O
stereoscope	B-Algorithm
to	O
present	O
the	O
left	O
image	O
to	O
the	O
left	O
eye	O
and	O
the	O
right	O
image	O
to	O
the	O
right	O
eye	O
or	O
focus	O
on	O
a	O
point	O
behind	O
the	O
image	O
to	O
achieve	O
the	O
same	O
thing	O
.	O
</s>
<s>
(	O
How	O
to	O
achieve	O
this	O
wall-eyed	O
position	O
of	O
the	O
eyes	O
is	O
described	O
in	O
Autostereogram	B-Algorithm
)	O
.	O
</s>
