<s>
A	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
(	O
VTS	O
)	O
is	O
a	O
user	O
interface	O
system	O
that	O
augments	O
virtual	O
objects	O
into	O
reality	O
either	O
through	O
a	O
projector	B-Application
or	O
optical	O
display	O
using	O
sensors	O
to	O
track	O
a	O
person	O
's	O
interaction	O
with	O
the	O
object	O
.	O
</s>
<s>
For	O
instance	O
,	O
using	O
a	O
display	O
and	O
a	O
rear	O
projector	B-Application
system	O
a	O
person	O
could	O
create	O
images	O
that	O
look	O
three-dimensional	O
and	O
appear	O
to	O
float	O
in	O
midair	O
.	O
</s>
<s>
Some	O
systems	O
utilize	O
an	O
optical	O
head-mounted	B-General_Concept
display	I-General_Concept
to	O
augment	O
the	O
virtual	O
objects	O
onto	O
the	O
transparent	O
display	O
utilizing	O
sensors	O
to	O
determine	O
visual	O
and	O
physical	O
interactions	O
with	O
the	O
virtual	O
objects	O
projected	O
.	O
</s>
<s>
2010	O
,	O
Displair	O
introduced	O
its	O
first	O
commercial	O
"	O
screenless	B-General_Concept
"	O
3D	O
virtual	O
multi-touch	B-Application
display	I-Application
,	O
consisting	O
of	O
cold	O
stable	O
air	O
flow	O
containing	O
particles	O
of	O
water	O
produced	O
by	O
a	O
cavitation	O
method	O
.	O
</s>
<s>
Late	O
2010	O
,	O
Microsoft	O
released	O
the	O
Kinect	B-Algorithm
,	O
a	O
first	O
of	O
a	O
kind	O
commercially	O
available	O
and	O
affordable	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
sensor	O
that	O
could	O
track	O
a	O
person	O
's	O
movement	O
and	O
augment	O
their	O
interactions	O
with	O
objects	O
rendered	O
in	O
a	O
television	O
set	O
.	O
</s>
<s>
2015	O
,	O
Microsoft	O
unveiled	O
the	O
Hololens	O
,	O
an	O
optical	O
head-mounted	B-General_Concept
display	I-General_Concept
utilizing	O
the	O
Windows	B-General_Concept
Holographic	I-General_Concept
platform	O
.	O
</s>
<s>
During	O
a	O
2009	O
study	O
at	O
the	O
Korea	O
Electronics	O
Technology	O
Institute	O
,	O
a	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
system	O
was	O
built	O
using	O
the	O
touch	O
point	O
tracking	O
technique	O
based	O
on	O
a	O
time	B-Device
of	I-Device
flight	I-Device
camera	I-Device
with	O
a	O
Kalman	O
filter	O
.	O
</s>
<s>
To	O
address	O
the	O
widespread	O
problem	O
in	O
conventional	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
systems	O
(	O
i.e.	O
</s>
<s>
Currently	O
,	O
virtual	B-Algorithm
touch	I-Algorithm
screens	I-Algorithm
(	O
VTS	O
)	O
are	O
used	O
primarily	O
for	O
entertainment	O
and	O
research	O
purposes	O
.	O
</s>
<s>
A	O
popular	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
system	O
is	O
the	O
Kinect	B-Algorithm
system	O
made	O
commercially	O
available	O
by	O
Microsoft	O
.	O
</s>
<s>
The	O
Kinect	B-Algorithm
system	O
is	O
primarily	O
used	O
for	O
consumer	O
entertainment	O
such	O
as	O
playing	O
games	O
and	O
using	O
the	O
menus	O
found	O
on	O
the	O
Xbox	B-Protocol
system	O
.	O
</s>
<s>
However	O
,	O
in	O
recent	O
years	O
the	O
Kinect	B-Algorithm
has	O
been	O
used	O
for	O
research	O
projects	O
in	O
the	O
field	O
of	O
robotics	O
and	O
3-D	O
interactions	O
outside	O
of	O
the	O
field	O
of	O
games	O
such	O
as	O
browsing	O
the	O
web	O
,	O
and	O
medical	O
practices	O
.	O
</s>
<s>
Virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
technology	O
can	O
also	O
be	O
applied	O
to	O
turn	O
non-touch	O
displays	O
into	O
interactive	O
,	O
touch-capable	O
surfaces	O
using	O
a	O
Kinect	B-Algorithm
sensor	O
in	O
combination	O
with	O
a	O
projector	B-Application
.	O
</s>
<s>
This	O
type	O
of	O
application	O
allows	O
virtual	O
touch	O
technology	O
to	O
enhance	O
personal	B-General_Concept
display	I-General_Concept
usage	O
as	O
well	O
as	O
better	O
communication	O
and	O
presentation	O
of	O
data	O
to	O
be	O
used	O
in	O
education	O
or	O
business	O
settings	O
.	O
</s>
<s>
Additionally	O
,	O
Microsoft	O
's	O
Kinect	B-Algorithm
sensor	O
has	O
also	O
employed	O
the	O
use	O
of	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
technology	O
to	O
help	O
stroke	O
patients	O
recover	O
and	O
improve	O
motor	O
function	O
in	O
their	O
limbs	O
through	O
a	O
game-like	O
system	O
involving	O
interpretation	B-General_Concept
of	I-General_Concept
gestures	I-General_Concept
combined	O
with	O
adjustable	O
difficulty	O
levels	O
based	O
on	O
the	O
user	O
's	O
performance	O
.	O
</s>
<s>
One	O
of	O
the	O
key	O
issues	O
with	O
virtual	B-Application
environments	I-Application
that	O
utilize	O
touch	O
are	O
the	O
haptics	B-Device
.	O
</s>
<s>
For	O
example	O
,	O
utilizing	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
for	O
medical	O
training	O
could	O
cut	O
costs	O
down	O
for	O
training	O
medical	O
staff	O
for	O
touch	O
delicate	O
operations	O
such	O
as	O
surgery	O
.	O
</s>
<s>
However	O
,	O
the	O
haptics	B-Device
of	O
such	O
training	O
does	O
not	O
provide	O
sufficient	O
physical	O
touch	O
feedback	O
necessary	O
for	O
a	O
virtually	O
trained	O
practitioner	O
to	O
perform	O
a	O
real	O
surgery	O
.	O
</s>
<s>
Incorporating	O
sufficient	O
haptic	O
feedback	O
to	O
virtual	B-Algorithm
touch	I-Algorithm
screen	I-Algorithm
interactions	O
is	O
an	O
active	O
area	O
of	O
research	O
.	O
</s>
