<s>
Gesture	B-General_Concept
recognition	I-General_Concept
is	O
a	O
topic	O
in	O
computer	B-General_Concept
science	I-General_Concept
and	O
language	B-Application
technology	I-Application
with	O
the	O
goal	O
of	O
interpreting	O
human	O
gestures	O
via	O
mathematical	O
algorithms	O
.	O
</s>
<s>
It	O
is	O
a	O
subdiscipline	O
of	O
computer	B-Application
vision	I-Application
.	O
</s>
<s>
Focuses	O
in	O
the	O
field	O
include	O
emotion	O
recognition	O
from	O
face	O
and	O
hand	B-General_Concept
gesture	I-General_Concept
recognition	I-General_Concept
since	O
they	O
are	O
all	O
expressions	O
.	O
</s>
<s>
Many	O
approaches	O
have	O
been	O
made	O
using	O
cameras	O
and	O
computer	B-Application
vision	I-Application
algorithms	O
to	O
interpret	O
sign	O
language	O
,	O
however	O
,	O
the	O
identification	O
and	O
recognition	O
of	O
posture	O
,	O
gait	O
,	O
proxemics	O
,	O
and	O
human	O
behaviors	O
is	O
also	O
the	O
subject	O
of	O
gesture	B-General_Concept
recognition	I-General_Concept
techniques	O
.	O
</s>
<s>
Gesture	B-General_Concept
recognition	I-General_Concept
can	O
be	O
seen	O
as	O
a	O
way	O
for	O
computers	O
to	O
begin	O
to	O
understand	B-General_Concept
human	I-General_Concept
body	I-General_Concept
language	I-General_Concept
,	O
thus	O
building	O
a	O
better	O
bridge	O
between	O
machines	O
and	O
humans	O
than	O
older	O
text	B-Application
user	I-Application
interfaces	I-Application
or	O
even	O
GUIs	B-Application
(	O
graphical	B-Application
user	I-Application
interfaces	I-Application
)	O
,	O
which	O
still	O
limit	O
the	O
majority	O
of	O
input	O
to	O
keyboard	B-Device
and	O
mouse	O
and	O
interact	O
naturally	O
without	O
any	O
mechanical	O
devices	O
.	O
</s>
<s>
Gesture	B-General_Concept
recognition	I-General_Concept
features	O
:	O
</s>
<s>
The	O
major	O
application	O
areas	O
of	O
gesture	B-General_Concept
recognition	I-General_Concept
in	O
the	O
current	O
scenario	O
are	O
:	O
</s>
<s>
Gesture	B-General_Concept
recognition	I-General_Concept
can	O
be	O
conducted	O
with	O
techniques	O
from	O
computer	B-Application
vision	I-Application
and	O
image	B-Algorithm
processing	I-Algorithm
.	O
</s>
<s>
The	O
literature	O
includes	O
ongoing	O
work	O
in	O
the	O
computer	B-Application
vision	I-Application
field	O
on	O
capturing	O
gestures	O
or	O
more	O
general	O
human	O
pose	B-Architecture
and	O
movements	O
by	O
cameras	O
connected	O
to	O
a	O
computer	O
.	O
</s>
<s>
Gesture	B-General_Concept
recognition	I-General_Concept
and	O
pen	O
computing	O
:	O
</s>
<s>
Pen	O
computing	O
reduces	O
the	O
hardware	O
impact	O
of	O
a	O
system	O
and	O
also	O
increases	O
the	O
range	O
of	O
physical	O
world	O
objects	O
usable	O
for	O
control	O
beyond	O
traditional	O
digital	O
objects	O
like	O
keyboards	B-Device
and	O
mice	O
.	O
</s>
<s>
The	O
term	O
"	O
gesture	B-General_Concept
recognition	I-General_Concept
"	O
has	O
been	O
used	O
to	O
refer	O
more	O
narrowly	O
to	O
non-text-input	O
handwriting	O
symbols	O
,	O
such	O
as	O
inking	O
on	O
a	O
graphics	B-Device
tablet	I-Device
,	O
multi-touch	B-Application
gestures	O
,	O
and	O
mouse	O
gesture	B-General_Concept
recognition	I-General_Concept
.	O
</s>
<s>
A	O
Touchless	O
user	B-Application
interface	I-Application
is	O
an	O
emerging	O
type	O
of	O
technology	O
based	O
on	O
gesture	B-General_Concept
control	I-General_Concept
.	O
</s>
<s>
Touchless	O
user	B-Application
interface	I-Application
(	O
TUI	O
)	O
is	O
the	O
process	O
of	O
commanding	O
the	O
computer	O
via	O
body	O
motion	O
and	O
gestures	O
without	O
touching	O
a	O
keyboard	B-Device
,	O
mouse	O
,	O
or	O
screen	O
.	O
</s>
<s>
Touchless	O
interfaces	O
in	O
addition	O
to	O
gesture	B-General_Concept
controls	I-General_Concept
are	O
becoming	O
widely	O
popular	O
as	O
they	O
provide	O
the	O
ability	O
to	O
interact	O
with	O
devices	O
without	O
physically	O
touching	O
them	O
.	O
</s>
<s>
Kinetic	O
user	B-Application
interfaces	I-Application
(	O
KUIs	O
)	O
are	O
an	O
emerging	O
type	O
of	O
user	B-Application
interfaces	I-Application
that	O
allow	O
users	O
to	O
interact	O
with	O
computing	O
devices	O
through	O
the	O
motion	O
of	O
objects	O
and	O
bodies	O
.	O
</s>
<s>
Examples	O
of	O
KUIs	O
include	O
tangible	O
user	B-Application
interfaces	I-Application
and	O
motion-aware	O
games	O
such	O
as	O
Wii	B-Operating_System
and	O
Microsoft	O
's	O
Kinect	B-Algorithm
,	O
and	O
other	O
interactive	O
projects	O
.	O
</s>
<s>
Although	O
there	O
is	O
a	O
large	O
amount	O
of	O
research	O
done	O
in	O
image/video	O
-based	O
gesture	B-General_Concept
recognition	I-General_Concept
,	O
there	O
is	O
some	O
variation	O
in	O
the	O
tools	O
and	O
environments	O
used	O
between	O
implementations	O
.	O
</s>
<s>
Wired	B-General_Concept
gloves	I-General_Concept
.	O
</s>
<s>
The	O
first	O
commercially	O
available	O
hand-tracking	O
glove-type	O
device	O
was	O
the	O
DataGlove	B-General_Concept
,	O
a	O
glove-type	O
device	O
that	O
could	O
detect	O
hand	O
position	O
,	O
movement	O
and	O
finger	O
bending	O
.	O
</s>
<s>
Light	O
pulses	O
are	O
created	O
and	O
when	O
the	O
fingers	O
are	O
bent	O
,	O
light	O
leaks	O
through	O
small	O
cracks	O
and	O
the	O
loss	O
is	O
registered	O
,	O
giving	O
an	O
approximation	O
of	O
the	O
hand	O
pose	B-Architecture
.	O
</s>
<s>
Using	O
specialized	O
cameras	O
such	O
as	O
structured	B-General_Concept
light	I-General_Concept
or	O
time-of-flight	O
cameras	O
,	O
one	O
can	O
generate	O
a	O
depth	O
map	O
of	O
what	O
is	O
being	O
seen	O
through	O
the	O
camera	O
at	O
a	O
short-range	O
,	O
and	O
use	O
this	O
data	O
to	O
approximate	O
a	O
3d	O
representation	O
of	O
what	O
is	O
being	O
seen	O
.	O
</s>
<s>
Stereo	B-Algorithm
cameras	I-Algorithm
.	O
</s>
<s>
An	O
example	O
of	O
emerging	O
gesture-based	O
motion	B-Application
capture	I-Application
is	O
skeletal	O
hand	B-Algorithm
tracking	I-Algorithm
,	O
which	O
is	O
being	O
developed	O
for	O
virtual	O
reality	O
and	O
augmented	O
reality	O
applications	O
.	O
</s>
<s>
An	O
example	O
of	O
this	O
technology	O
is	O
shown	O
by	O
tracking	O
companies	O
uSens	B-General_Concept
and	O
Gestigon	B-General_Concept
,	O
which	O
allow	O
users	O
to	O
interact	O
with	O
their	O
surroundings	O
without	O
controllers	O
.	O
</s>
<s>
A	O
standard	O
2D	O
camera	O
can	O
be	O
used	O
for	O
gesture	B-General_Concept
recognition	I-General_Concept
where	O
the	O
resources/environment	O
would	O
not	O
be	O
convenient	O
for	O
other	O
forms	O
of	O
image-based	O
recognition	O
.	O
</s>
<s>
Software-based	O
gesture	B-General_Concept
recognition	I-General_Concept
technology	O
using	O
a	O
standard	O
2D	O
camera	O
that	O
can	O
detect	O
robust	O
hand	O
gestures	O
.	O
</s>
<s>
Some	O
literature	O
differentiates	O
2	O
different	O
approaches	O
in	O
gesture	B-General_Concept
recognition	I-General_Concept
:	O
a	O
3D	O
model-based	O
and	O
an	O
appearance-based	O
.	O
</s>
<s>
Volumetric	O
approaches	O
have	O
been	O
heavily	O
used	O
in	O
the	O
computer	O
animation	O
industry	O
and	O
for	O
computer	B-Application
vision	I-Application
purposes	O
.	O
</s>
<s>
There	O
are	O
many	O
challenges	O
associated	O
with	O
the	O
accuracy	O
and	O
usefulness	O
of	O
gesture	B-General_Concept
recognition	I-General_Concept
software	O
.	O
</s>
<s>
For	O
image-based	O
gesture	B-General_Concept
recognition	I-General_Concept
,	O
there	O
are	O
limitations	O
on	O
the	O
equipment	O
used	O
and	O
image	B-Algorithm
noise	I-Algorithm
.	O
</s>
<s>
The	O
variety	O
of	O
implementations	O
for	O
image-based	O
gesture	B-General_Concept
recognition	I-General_Concept
may	O
also	O
cause	O
issues	O
with	O
the	O
viability	O
of	O
the	O
technology	O
for	O
general	O
usage	O
.	O
</s>
<s>
In	O
order	O
to	O
capture	O
human	O
gestures	O
by	O
visual	O
sensors	O
,	O
robust	O
computer	B-Application
vision	I-Application
methods	O
are	O
also	O
required	O
,	O
</s>
<s>
for	O
example	O
for	O
hand	B-Algorithm
tracking	I-Algorithm
and	O
hand	O
posture	O
recognition	O
or	O
for	O
capturing	O
movements	O
of	O
the	O
head	O
,	O
facial	O
expressions	O
or	O
gaze	O
direction	O
.	O
</s>
<s>
One	O
significant	O
challenge	O
to	O
the	O
adoption	O
of	O
gesture	B-General_Concept
interfaces	I-General_Concept
on	O
consumer	O
mobile	B-Application
devices	I-Application
such	O
as	O
smartphones	O
and	O
smartwatches	O
stems	O
from	O
the	O
social	O
acceptability	O
implications	O
of	O
gestural	O
input	O
.	O
</s>
<s>
Gesture	B-General_Concept
interfaces	I-General_Concept
on	O
mobile	O
and	O
small	O
form-factor	O
devices	O
are	O
often	O
supported	O
by	O
the	O
presence	O
of	O
motion	O
sensors	O
such	O
as	O
inertial	O
measurement	O
units	O
(	O
IMUs	O
)	O
.	O
</s>
<s>
The	O
social	O
acceptability	O
of	O
mobile	B-Application
device	I-Application
gestures	O
relies	O
heavily	O
on	O
the	O
naturalness	O
of	O
the	O
gesture	O
and	O
social	O
context	O
.	O
</s>
<s>
Wearable	B-Operating_System
computers	I-Operating_System
typically	O
differ	O
from	O
traditional	O
mobile	B-Application
devices	I-Application
in	O
that	O
their	O
usage	O
and	O
interaction	O
location	O
takes	O
place	O
on	O
the	O
user	O
's	O
body	O
.	O
</s>
<s>
In	O
these	O
contexts	O
,	O
gesture	B-General_Concept
interfaces	I-General_Concept
may	O
become	O
preferred	O
over	O
traditional	O
input	O
methods	O
,	O
as	O
their	O
small	O
size	O
renders	O
touch-screens	B-Device
or	O
keyboards	B-Device
less	O
appealing	O
.	O
</s>
<s>
Nevertheless	O
,	O
they	O
share	O
many	O
of	O
the	O
same	O
social	O
acceptability	O
obstacles	O
as	O
mobile	B-Application
devices	I-Application
when	O
it	O
comes	O
to	O
gestural	O
interaction	O
.	O
</s>
<s>
However	O
,	O
the	O
possibility	O
of	O
wearable	B-Operating_System
computers	I-Operating_System
being	O
hidden	O
from	O
sight	O
or	O
integrated	O
into	O
other	O
everyday	O
objects	O
,	O
such	O
as	O
clothing	O
,	O
allow	O
gesture	O
input	O
to	O
mimic	O
common	O
clothing	O
interactions	O
,	O
such	O
as	O
adjusting	O
a	O
shirt	O
collar	O
or	O
rubbing	O
one	O
's	O
front	O
pant	O
pocket	O
.	O
</s>
<s>
A	O
major	O
consideration	O
for	O
wearable	B-Operating_System
computer	I-Operating_System
interaction	O
is	O
the	O
location	O
for	O
device	O
placement	O
and	O
interaction	O
.	O
</s>
<s>
A	O
study	O
exploring	O
third-party	O
attitudes	O
towards	O
wearable	O
device	O
interaction	O
conducted	O
across	O
the	O
United	O
States	O
and	O
South	O
Korea	O
found	O
differences	O
in	O
the	O
perception	O
of	O
wearable	B-Operating_System
computing	I-Operating_System
use	O
of	O
males	O
and	O
females	O
,	O
in	O
part	O
due	O
to	O
different	O
areas	O
of	O
the	O
body	O
considered	O
socially	O
sensitive	O
.	O
</s>
<s>
While	O
touch	B-Device
screens	I-Device
are	O
a	O
frequent	O
form	O
of	O
input	O
for	O
public	O
displays	O
,	O
gesture	B-General_Concept
interfaces	I-General_Concept
provide	O
additional	O
benefits	O
such	O
as	O
improved	O
hygiene	O
,	O
interaction	O
from	O
a	O
distance	O
,	O
and	O
improved	O
discoverability	O
,	O
and	O
may	O
favor	O
performative	O
interaction	O
.	O
</s>
<s>
"	O
Gorilla	O
arm	O
"	O
was	O
a	O
side-effect	O
of	O
vertically	O
oriented	O
touch-screen	B-Device
or	O
light-pen	O
use	O
.	O
</s>
<s>
This	O
effect	O
contributed	O
to	O
the	O
decline	O
of	O
touch-screen	B-Device
input	O
despite	O
its	O
initial	O
popularity	O
in	O
the	O
1980s	O
.	O
</s>
