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Camera-less Smart Laser Projector
Author:
Alvaro Cassinelli∗, Alexis Zerroug, and Masatoshi
Ishikawa
Ishikawa-Komuro Laboratory, University of Tokyo
Jussi Angesleva
The Berlin University of the Arts
--------------SIGGRAPH 2010 Emerging Technology
TNUA M9893010 Virtual Reality 陳育羣
Outline
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Abstract
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Introduction
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Previous work 'Sticky Light'
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New prototype and apps
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Technical details
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Hardware and setup
Abstract
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Smart laser projector
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'Augmenting' surfaces
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Prototype :
1. Sticky Light : Contours of drawing or Bouncing on flat figure
2. simulation of the refraction of light beams on 2d surface
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Snell Law
1. Introduction
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Raster scanning mode or Vector mode
sensing and scanning the surface
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Advantages :
[1]
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Calibration is not needed at all
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Stereo Scan :Vein Viewer [3], infrared camera+DLP
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Extremly large depth of focus
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Variable resolution
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Simple and Compact optical system
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Projection at very long distance
1. Introduction cont.
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Applications of SLP:
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Translation of barcode information into directly readable text
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Augmentation of paintings, mural Ad. and logos using laser light
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Automatic contrast compensation
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Medical imaging, biosensing and biometrics.
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Advantage Architectural Spaces
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Spatial cueing
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Exo-displays
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Entertainment
1. Introduction cont.
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Problems :
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Real – time extraction of relevant 3D features, radiometric properties,
texture, speed and even temperature of the illuminated surface.
This research is build on 'smart laser scanner' [7]
and experiments on real-time scanning and
projection of deformable surface using active
lighting and a custom vision chip [8]
2.Previous work 'Sticky Light'
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Air-hockey, Pin ball game
It actually augmented the drawing content by
scanning the lines and bouncing on the colors.
3.New Prototype and Apps
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Bouncing on lines and edges
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The scanned material cab be virtually anything.
The needed is that scanned object presen
enought contrast for the scanning beam,
Ray tracing
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Note the scanning 'saccade' at the intterface between gray areas, and
the deviation of the 'beam' following a simulated Snell Law.
4.Technical Details
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Baced on 3D tracking technology.
Previeous Developed is 'smart laser scanner' [7]
In the near future, it will use an RGB laser projector
for completing the color palette.(RG)
Hardware:
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Arduino Mega
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Custom made Lock-In amplifier
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A laser head projector of two laser diodes(r and g)
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Couple of galvano mirrors.(could be steering )
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A sigle non-imaging photodetector.
4.Technical Details cont.
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Processing:
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The microcontroller reads the lock-in amplifier output signal to
discriminate between dark and bright zones (and a discrete number of
gray levels).
It also controls the position of the laser spot by generating analog signals
driving the X/Y galvano-mirror pair.
In such case, it generates a circular scanning saccade in order to compute
the normal vector to the interface between the two different regions.
From this information, it is straightforward to compute either the bouncing or
the refracting direction.
5. Hardware and Setup
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The overall size is about
30x30x40cm
6. Conclusion
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We have demonstrated a portable prototype of a ‘smart laser pro-jector’
having endless applications from entertainment, to human computer
interfaces to medical imaging.
In the near future, we plan to demonstrate medical imaging applications
(in the field of derma-tology and phlebo therapy), as well as research on
ways to rendering the whole system compatible with a hand-held instrument
using MEMS technology.
Thanks for your attention.