Mitsubishi Electric Research Laboratories August 2006
Mitsubishi Electric Research Labs (MERL)Cambridge, MA
Instant Replay: Inexpensive Instant Replay: Inexpensive High Speed Motion CaptureHigh Speed Motion Capture
Hideaki Nii, Jay Summet, Yong Zhao, Jonathan Westhues, Paul H. Dietz, Shree K. Nayar, John Barnwell, Michael Noland, Vlad Branzoi, Erich Bruns, Masahiko Inami, & Ramesh Raskar
Mitsubishi Electric Research Laboratories August 2006
Optical CaptureOptical Capture
• Goal– Find 2D or 3D location of tags
• Approach– Each tag has a photosensor– Label space using zones created by special
high speed projectors– Find zone in which the tag lies
Mitsubishi Electric Research Laboratories August 2006
Key FeaturesKey Features
• 500 Hz Tracking• Id for each Marker Tag• Capture in Natural Environment
– Visually imperceptible tags– Photosensing Tag can be hidden under clothes– Ambient lighting is ok
• Unlimited Number of Tags Allowed• Base station and tags only a few 10’s $
Mitsubishi Electric Research Laboratories August 2006
Potential ApplicationsPotential Applications
• High Speed Motion Capture & Tracking– Motion Capture
• Character Animation• CG alignment
– Industrial applications• Crash Test Dummies• Robot Guidance
– Indoor Positioning for Ubiquitous Computing• Locating users and devices• 3D User Input
Mitsubishi Electric Research Laboratories August 2006
Existing SolutionsExisting Solutions
• Optical: Uses expensive cameras to locate tags in the environment.– Passive tags give location, but no identity,
leading to reacquisition problems
• Magnetic– Environmental interference, expensive
• Inertial Tracking (Gyro/ Compass)– Drift, Calibration
Mitsubishi Electric Research Laboratories August 2006
Solution OverviewSolution Overview
• Use inexpensive solid state projectors to “label space”.– Solid State lighting (LED’s) can be
modulated extremely quickly (MHz to GHz).
• Each point in space receives a different code sequence.
• Inexpensive and small tags receive the codes, and can detect their own location.
Mitsubishi Electric Research Laboratories August 2006
Labeling SpaceLabeling Space
Each tag receives a
unique signal based upon it’s
physical location.
P rojec tor
T ags
P os=0
P os=255
Mitsubishi Electric Research Laboratories August 2006
How Labeling WorksHow Labeling WorksLightsourc
e
GrayCode Mask
Optics
Screen
Light source blink one by one and each position on the screen has different light pattern.
4 light make 4 bit position resolution
pos=0 pos=15
Mitsubishi Electric Research Laboratories August 2006
System HardwareSystem Hardware
• One projector can send 10 bit one dimensional position data.
• No limitation on the number of tags.
PIC16F873+LED driver
IR LE D IR rece ive rT S O P 7000
SY N C IN
S Y N C O U T
P IC 18F2620
M em ory
W ire lesscom m uni
ca tion
P ro jector Tag
455kH zm odulatedIR signal
Mitsubishi Electric Research Laboratories August 2006
Inside of ProjectorInside of Projector
The Gray code pattern
Focusing Optics
Gray code Slide
Condensing Optics Light Source
Mitsubishi Electric Research Laboratories August 2006
SpecificationSpecification
Name Value Remarks
Measurement time
1 mS Per one dimension
FOV 26.7 deg.
Resolution 10 bit
Operational Range
1m ~ 5m Good quality in 2m~4m area.
Mitsubishi Electric Research Laboratories August 2006
Low costLow cost
Proto type system Mass Produced System•Projector
Electrical parts:$50
Projector body:$10
Optics: $ hundreds
(4 custom glass lenses)
•Tag
Electrical parts:$50
Wireless unit:$50
•Projector
Electrical parts:$30
Projector body:$10
Optics:$10 (Plastic lens)
•Tag
Electrical parts:$10
Wireless unit: Optional
Mitsubishi Electric Research Laboratories August 2006
Expand to 2D/3D SystemExpand to 2D/3D System
2D measurement 3D measurement
Y data
X data
Y data
X dataX2 data
Mitsubishi Electric Research Laboratories August 2006
Tags Hidden Under CostumeTags Hidden Under Costume
• Tags can be hidden under an actors costume with only small sensors exposed.• This enables motion capture during primary filming.
Mitsubishi Electric Research Laboratories August 2006
Key FeaturesKey Features
• 500 Hz Tracking• Id for each Marker Tag• Capture in Natural Environment
– Visually imperceptible tags– Photosensing Tag can be hidden under clothes– Ambient lighting is ok
• Unlimited Number of Tags Allowed• Base station and tags only a few 10’s $
Mitsubishi Electric Research Laboratories August 2006
Take Away PointsTake Away Points• Very Inexpensive Projectors and Tags.
• Reasonable accuracy which will be improved with better optical design.
• Very fast sampling rates possible!
• We want to license the technology!
Mitsubishi Electric Research Laboratories August 2006
Thank you!Thank you!
Contact:
Ramesh Raskar [email protected]