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sSmart Light –Ultra High Speed Projector for Spatial Multiplexing Optical Transmission
Hideaki NII, Maki SUGIMOTO, Masahiko INAMI
The University of Erectro-Communications, JAPAN
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Table of contents
• Introduction– Camera vs. Projector– Comparison of characteristics
• Smart light concept (next to projector)
• Preliminary experiment• The design of LED projector• Experiment of LED projector• Conclusion
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Projector vs. video camera
• Acquire images.• Acquire
information with images
• Project images• Project
information with images.
Camera Projector
A projector is the dual of a camera. R Raskar, iLamps,2003
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Basic concept of image-processing
Camera (1)we send position data by LED,(2)acquire images by video camera, (3)processing and recoginize a position, (4) get (X,Y) position data.
deviceCCD
(X,Y)LED× 1
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Basic concept of projector image processing
Projector(1) we project color images depending on its x-cordinate or Y-cordinate position, (2) a device acquire color values by color sensor,(3) get (X,Y) position data.
deviceprojector
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Projector-Based Tracking SystemDemonstrated at SIGGRAPH2004
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Augmented ColiseumTo be Demonstrated at
SIGGRAPH2005
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A compact battery-less information terminal (CoBIT) for location-based support systems
Takuichi Nishimura, SPIE, number 4863B-12, 2002
CoBIT can project various kinds of information according to a position. But LED light can project only single sound.
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RFIG Lamp
• Use RFID and a portable projector to display RFID tag’s location directly.
http://www.merl.com/people/raskar/Sig04/
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Smart light concept
• Use projector and camera to communicate to detached device.
• To increase band-width, use space division .
Make invisibleinfomation
make vision
Computer
Capture image from camera
High speed camera
Devices
Projector
+
Half mirror
Control module
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Why LED projector ?
Most high-speed pixel :LED
Class Frame rate
LCD projector 60[Hz]
DMD projector
10,000[Hz]
LED projector 10,000,000[Hz]
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Preliminary experiment
Photo detectorPICReceiveLED
Projector
averageregister
Pulse widthto digital
+
-comp
wave formstabilizer
sensorinput
Detectoutput PIC internal
function
Image A
Image B
20HzOSCImage A Image B
AMP
Luminance of A and B (cd/m2)
Response from detector
Response from subject
82;82 No No
82;88 Yes Yes
82;95 Yes Yes
77;77 No No
77;72 Yes No
77;67 Yes Yes
Result
Detector
Experimental setup
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Experiment of LED projector
A B
B
A
0 28.8
30.4
30.5 65.0
O nly A
A and B
O nly B
[m m]
7.2m
m
L E D -BL E N S S C R E E N
L E D -AC irc le o f B
C irc le o f A
Result
Positional relationship
LE D
Camera
Lens
S creen
Photosensor
FM modulation
FM modulation FM demodulation
Headphone
Experimental setup
To check the signal separation quality. We prepare this experimental set.
50mm 300mm
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LED projector
• Can project small image for human’s eye
• Can project invisible information (sound/video stream) .
• Different data stream to each pixel.
• Projection pattern can change in real time.
• Subject can select the point by the detector and get data stream with no time delay.
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Components of LED projector
InputA
InputB
InputC
InputD
Selector
AMP
AMP
AMP
AMP
AMP
Select Input-signal from communication I/FRS232C
Selector
Selector
Selector
OSC
OSC
OSC
OSC
LED1
LED2
LED3
LED4
LED20
6mm 8.5mm
6mm
7.5m
m
40mm
29mm
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Experiment of LED projector
lens
detector1
detector2
spatial light modulator
time-spatial modulation light
detector3
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Experiment of LED projector
LED projector and signal generator Photo detector and headset
Portable musicplayer(MUSIC)
Portable musicplayer(NOISE)
FM modulation
FM modulation
LED Prjector
Pixel luminance and input sound controller
FM de-modulation
Photo detector
Headphone
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Characteristic of this experiment
• Subject can see bright area and dark area on the screen.
• The bright area has music stream for the headphone, and the dark area has noise.
• Subject can select the point by the detector and hear a sound stream with no time delay.
• The bright area has move in rhythm of the music.
• As the result, subject can move a detector in rhythm of music and listen a music continuously.
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Conclusion
• Concept of “Smart light”.• Fundamental experiment of LED
projector.• Design of LED projector.• The experiment of LED projector.