Micro-controller based sensor localization and tracking using
projected light patterns.
Introduction: Displaying an image on an arbitrary surface requires that
you know where the surface is located within the projection area.
Other methods including manual calibration and camera based calibration are either
time consuming, labor intensive, or error prone. We augment the display
surface with an electronic light sensor which can determine its own position
and report back to the projector via radio.
Additionally, our system can track the sensor as it moves in real
time using a small tracking pattern, allowing mobile projection
We used a Microchip rfPIC 12F675 with:
4Mhz RISC Processor
1024 program words (we used 858 )
64 bytes of RAM (we used 50)
Integrated Analog-to-Digital converter
UHF ASK 10dBm radio transmitter.
A hardware sensor which determines its physical location with
respect to a projected pattern.
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Radio receiver to computer interface circuit.
Tracking the sensor
After the initial localization stage, a hexagonal tracking pattern is
used to track the sensor. When the sensor is not moving, the tracking
pattern can be shrunk to cover only the sensor itself.
Tracking a display surface
After localizing the sensor, a hexagonal tracking pattern is used to continue
sending location data to the sensor while freeing up most of the projection area
for display purposes. The intersection of the green and red lines indicate the
current location of the sensor, and are visible for illustrative purposes only.
A simple display screen with one sensor, allowing two dimensions of motion.
Placing sensors on the other corners of the surface would allow the projector to
track the quadrangle where the display should appear, and warp the image
appropriately as the display is moved arbitrarily in 3-space.
Automatic Projector Calibration with Embedded Light Sensors
Johnny C. Lee, Paul H. Dietz, Dan Maynes-Aminzade, Ramesh
Raskar and Scott Hudson. Proceedings of UIST 2004.
RFIG Lamps: Interacting with a Self-describing World via
Photosensing Wireless Tags and Projectors
Ramesh Raskar, Paul Beardsley, Jeroen van Baar, Yao Wang, Paul Dietz,
Johnny Lee, Darren Leigh, Thomas Willwacher
Proceedings of SIGGRAPH 2004.