<s>
A	O
handheld	B-General_Concept
projector	I-General_Concept
(	O
also	O
known	O
as	O
a	O
pocket	B-General_Concept
projector	I-General_Concept
,	O
mobile	O
projector	B-Application
,	O
pico	B-General_Concept
projector	I-General_Concept
or	O
mini	O
beamer	O
)	O
is	O
an	O
image	B-Application
projector	I-Application
in	O
a	O
handheld	B-Application
device	I-Application
.	O
</s>
<s>
It	O
was	O
developed	O
as	O
a	O
computer	B-Device
display	I-Device
device	O
for	O
compact	O
portable	B-Application
devices	I-Application
such	O
as	O
mobile	O
phones	O
,	O
personal	B-Application
digital	I-Application
assistants	I-Application
,	O
and	O
digital	B-Device
cameras	I-Device
,	O
which	O
have	O
sufficient	O
storage	O
capacity	O
to	O
handle	O
presentation	O
materials	O
but	O
are	O
too	O
small	O
to	O
accommodate	O
a	O
display	B-Device
screen	I-Device
that	O
an	O
audience	O
can	O
see	O
easily	O
.	O
</s>
<s>
Handheld	B-General_Concept
projectors	I-General_Concept
involve	O
miniaturized	O
hardware	O
,	O
and	O
software	O
that	O
can	O
project	O
digital	O
images	O
onto	O
a	O
nearby	O
viewing	O
surface	O
.	O
</s>
<s>
An	O
important	O
design	O
characteristic	O
of	O
a	O
handheld	B-General_Concept
projector	I-General_Concept
is	O
the	O
ability	O
to	O
project	O
a	O
clear	O
image	O
on	O
various	O
viewing	O
surfaces	O
.	O
</s>
<s>
Major	O
advances	O
in	O
imaging	O
technology	O
have	O
allowed	O
the	O
introduction	O
of	O
hand-held	B-Application
(	O
pico	O
)	O
type	O
video	B-Device
projectors	I-Device
.	O
</s>
<s>
Various	O
manufacturers	O
have	O
produced	O
handheld	B-General_Concept
projectors	I-General_Concept
exhibiting	O
high-resolution	O
,	O
good	O
brightness	O
,	O
and	O
low	O
energy	O
consumption	O
in	O
a	O
slightly	O
larger	O
format	O
than	O
pico	O
since	O
2008	O
.	O
</s>
<s>
However	O
,	O
most	O
handheld	B-Application
LED	O
projectors	B-Application
,	O
as	O
of	O
December	O
2017	O
,	O
have	O
been	O
widely	O
criticized	O
for	O
having	O
insufficient	O
brightness	O
for	O
everyday	O
use	O
in	O
a	O
normally	O
lit	O
room	O
.	O
</s>
<s>
In	O
2011	O
,	O
Texas	O
Instruments	O
DLP	B-General_Concept
announced	O
improved	O
chipsets	B-Device
that	O
enable	O
brighter	O
images	O
,	O
and	O
LED	O
advances	O
were	O
such	O
that	O
pico	B-General_Concept
projectors	I-General_Concept
using	O
that	O
technology	O
were	O
also	O
increasing	O
in	O
brightness	O
.	O
</s>
<s>
The	O
DLP	B-General_Concept
chip	B-Device
sets	I-Device
are	O
designed	O
to	O
enhance	O
image	O
brightness	O
without	O
increasing	O
power	O
usage	O
for	O
both	O
WVGA	O
(	O
native	O
DVD	O
resolution	O
)	O
devices	O
,	O
such	O
as	O
mobile	O
phones	O
,	O
and	O
VGA	B-Protocol
devices	O
,	O
such	O
as	O
digital	B-Device
cameras	I-Device
and	O
camcorders	O
.	O
</s>
<s>
The	O
chip	B-Device
sets	I-Device
have	O
the	O
ability	O
to	O
project	O
an	O
image	O
up	O
to	O
(	O
1270mm	O
)	O
on	O
any	O
surface	O
in	O
optimum	O
lighting	O
conditions	O
.	O
</s>
<s>
In	O
2014	O
Texas	O
Instruments	O
DLP	B-General_Concept
's	O
imagers	O
occupied	O
a	O
significant	O
portion	O
of	O
the	O
handheld	B-General_Concept
projector	I-General_Concept
market	O
share	O
.	O
</s>
<s>
In	O
combination	O
with	O
Osram	O
's	O
Ostar	O
series	O
LEDs	O
optical	O
engines	O
based	O
on	O
DLP	B-General_Concept
technology	O
have	O
achieved	O
over	O
15	O
lumens	O
per	O
watt	O
for	O
high	O
brightness	O
applications	O
(	O
300	O
–	O
500	O
lumens	O
with	O
0.45	O
"	O
imager	O
)	O
and	O
over	O
20	O
lumens	O
per	O
watt	O
in	O
low	O
brightness	O
applications	O
(	O
10	O
–	O
50	O
lumens	O
with	O
0.2	O
"	O
or	O
0.3	O
"	O
imagers	O
)	O
.	O
</s>
<s>
Three	O
major	O
image	O
technologies	O
for	O
micro	B-General_Concept
projectors	I-General_Concept
are	O
commonplace	O
:	O
</s>
<s>
LCoS	B-Device
(	O
Liquid	B-Device
crystal	I-Device
on	I-Device
silicon	I-Device
)	O
manufacturers	O
including	O
Syndiant	O
,	O
Himax	O
,	O
Micron	O
Technologies	O
and	O
Omnivision	O
can	O
usually	O
supply	O
companies	O
with	O
both	O
LED	O
and	O
laser	O
versions	O
.	O
</s>
<s>
Most	O
micro	B-General_Concept
projectors	I-General_Concept
employ	O
one	O
of	O
these	O
imagers	O
,	O
combined	O
with	O
color-sequential	O
(	O
RGB	O
)	O
LEDs	O
in	O
either	O
a	O
single	O
or	O
triple	O
architecture	O
format	O
.	O
</s>
<s>
Manufacturers	O
that	O
have	O
adopted	O
this	O
technology	O
include	O
Digislide	O
,	O
Optoma	O
's	O
PK201	O
/	O
PK301	O
(	O
DLP	B-General_Concept
)	O
,	O
3M	O
's	O
MPro	O
160	O
/	O
180	O
(	O
LCoS	B-Device
)	O
,	O
Aiptek	O
's	O
V50	O
(	O
DLP	B-General_Concept
)	O
,	O
AAXA	O
's	O
M2	O
(	O
LCoS	B-Device
)	O
,	O
Bonitor	O
MP302	O
(	O
LCos	B-Device
)	O
,	O
Micron	O
's	O
PoP	O
Video	O
(	O
LCoS	B-Device
)	O
,	O
and	O
Vivitek	O
's	O
High	O
Definition	O
Qumi	O
(	O
DLP	B-General_Concept
)	O
.	O
</s>
<s>
Some	O
older	O
models	O
incorporated	O
a	O
single	O
LCoS	B-Device
imager	O
chip	O
with	O
single	O
white	O
LED	O
for	O
low	O
cost	O
,	O
high	O
resolution	O
,	O
and	O
fast	O
response	O
at	O
the	O
expense	O
of	O
color	O
quality	O
.	O
</s>
<s>
Other	O
micro	B-General_Concept
projectors	I-General_Concept
employ	O
RGB	O
laser	O
technology	O
,	O
such	O
as	O
Microvision	O
's	O
beam-steering	O
plus	O
laser	O
technology	O
,	O
and	O
AAXA	O
's	O
laser	O
plus	O
LCoS	B-Device
technology	O
.	O
</s>
<s>
For	O
example	O
,	O
while	O
DLP	B-General_Concept
typically	O
has	O
slightly	O
lower	O
resolution	O
than	O
their	O
LCoS	B-Device
counterparts	O
due	O
to	O
the	O
tiny	O
mirrors	O
used	O
in	O
DLP	B-General_Concept
technology	O
,	O
3-LED	O
DLP	B-General_Concept
projectors	I-General_Concept
are	O
generally	O
regarded	O
as	O
having	O
a	O
higher	O
contrast	O
,	O
better	O
efficiency	O
and	O
lower	O
power	O
consumption	O
as	O
opposed	O
color-sequential	O
LCoS	B-Device
units	O
and	O
better	O
color	O
quality	O
than	O
white	O
LED	O
LCoS	B-Device
units	O
.	O
</s>
<s>
Laser	B-General_Concept
scanning	I-General_Concept
projectors	I-General_Concept
such	O
as	O
Microvision	O
's	O
ShowX	O
and	O
AAXA	O
's	O
L1	O
offer	O
very	O
good	O
color	O
gamut	O
and	O
low	O
power	O
consumption	O
due	O
to	O
the	O
use	O
of	O
lasers	O
as	O
the	O
light	O
source	O
and	O
also	O
present	O
an	O
image	O
that	O
is	O
always	O
in	O
focus	O
.	O
</s>
<s>
The	O
new	O
"	O
Direct	O
Green	O
Laser	O
"	O
(	O
DGL	O
)	O
technologies	O
that	O
replace	O
the	O
"	O
pumped	O
green	O
laser	O
"	O
in	O
next	O
generation	O
laser	O
projectors	B-Application
,	O
in	O
combination	O
with	O
improved	O
hardware	O
optics	O
,	O
MEMS	B-General_Concept
Mirror	O
designs	O
and	O
other	O
operational	O
methods	O
,	O
are	O
being	O
deployed	O
or	O
are	O
under	O
development	O
.	O
</s>
<s>
Handheld	B-General_Concept
projectors	I-General_Concept
can	O
be	O
used	O
for	O
different	O
applications	O
from	O
small	O
conventional	O
projectors	B-Application
.	O
</s>
<s>
Since	O
2008	O
researchers	O
are	O
studying	O
applications	O
that	O
are	O
specifically	O
designed	O
for	O
handheld	B-General_Concept
projectors	I-General_Concept
often	O
using	O
prototypes	O
of	O
mobile	O
phones	O
with	O
an	O
integrated	O
projector	B-Application
.	O
</s>
<s>
Projector	B-Application
phones	O
allow	O
sharing	O
them	O
with	O
a	O
larger	O
audience	O
than	O
on	O
the	O
phone	O
's	O
small	O
screen	O
.	O
</s>
<s>
One	O
study	O
found	O
that	O
people	O
preferred	O
to	O
view	O
and	O
share	O
photos	O
with	O
projector	B-Application
phones	O
,	O
compared	O
to	O
using	O
conventional	O
mobile	O
phones	O
.	O
</s>
<s>
Handheld	B-General_Concept
projectors	I-General_Concept
,	O
in	O
particular	O
projector	B-Application
phones	O
,	O
could	O
offer	O
new	O
possibilities	O
for	O
mobile	O
gaming	O
,	O
as	O
demonstrated	O
by	O
the	O
adaptation	O
of	O
the	O
PlayStation	B-Operating_System
3	I-Operating_System
game	O
LittleBigPlanet	B-Application
.	O
</s>
<s>
Size	O
reduction	O
of	O
mobile	B-Application
devices	I-Application
is	O
often	O
limited	O
by	O
the	O
size	O
of	O
the	O
used	O
display	O
.	O
</s>
<s>
It	O
has	O
been	O
demonstrated	O
that	O
pico	B-General_Concept
projectors	I-General_Concept
integrated	O
in	O
headsets	O
could	O
be	O
used	O
as	O
interaction	O
devices	O
,	O
e.g.	O
,	O
using	O
additional	O
hand	O
and	O
finger	B-Algorithm
tracking	I-Algorithm
.	O
</s>
<s>
The	O
MIT	O
Media	O
Lab	O
proposed	O
a	O
wearable	O
gestural	B-General_Concept
interface	I-General_Concept
device	O
named	O
SixthSense	B-General_Concept
.	O
</s>
<s>
Chris	O
Harrison	O
developed	O
a	O
working	O
system	O
called	O
Omnitouch	B-Device
.	O
</s>
<s>
Lisa	O
Cowan	O
from	O
UCSD	O
showed	O
a	O
proof	O
of	O
concept	O
of	O
gesture	B-General_Concept
recognition	I-General_Concept
using	O
shadow-occluding	O
of	O
the	O
projector	B-Application
,	O
called	O
ShadowPuppets	O
.	O
</s>
<s>
A	O
modified	O
laser	O
projector	B-Application
has	O
been	O
used	O
to	O
perform	O
gesture	B-General_Concept
recognition	I-General_Concept
and	O
finger	B-Algorithm
tracking	I-Algorithm
using	O
laser-based	O
active	O
tracking	O
techniques	O
at	O
the	O
University	O
of	O
Tokyo	O
(	O
and	O
)	O
.	O
</s>
<s>
Combining	O
a	O
pico	B-General_Concept
projector	I-General_Concept
with	O
a	O
webcam	B-Protocol
,	O
a	O
laser	O
pointer	O
,	O
and	O
image	O
processing	O
software	O
enables	O
full	O
control	O
of	O
any	O
computing	O
system	O
via	O
the	O
laser	O
pointer	O
.	O
</s>
