Transcript MDR Slides

L3PT
Large Portable Projected Peripheral
Touchscreen
Team Jackson
Brian Gosselin
Greg Langlois
Nick Jacek
Dmitry Kovalenkov
Midway Design Review
Electrical and Computer Engineer ing
Project Overview
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Portable
Large workspace
Affordable
Single / Multi user
Multi touch capabilities
No other product currently on
the market meets all these
specifications.
Electrical and Computer Engineering
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System Block Diagram
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MicroVision SHOWWX Laser Pico Projector
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Small: .55” x 2.36” x 4.64”
Light: 122g
Resolution: 849 x 480
Image Size: 6” to 100”
This projector provides the best
resolution and size within budget.
Electrical and Computer Engineering
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Microsoft LifeCam vx-2000
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Purchased for prototyping
Processes up to 30 fps
Removed visible light filter
Replaced with IR longpass filter
For the final design, we may
need to upgrade to a faster
camera to minimize delay.
Electrical and Computer Engineering
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Image Processing
• Touch locations
correspond with
brightest areas
• Distinguishes between
touch pixels and
background pixels
• Finds coordinates of
touches
• Coding in C++
• Utilizing OpenCV
libraries
Electrical and Computer Engineering
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Image Processing – Algorithm # 1
• Scans image for first
touch pixel
• Records location of touch
• Draws black circle to
cover brightest region
• Saves touch coordinates
• Sometimes more than 1
coordinate per touch
• Very fast and simple
Electrical and Computer Engineering
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Image Processing – Algorithm # 2
• Finds bounding rectangle of
touch region
• Assigns center of rectangle
as the touch location
• Always only 1 coordinate
per touch
• More complex and slower
than algorithm 1
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Speed Of Image Processing
 Algorithm # 1 has complexity O(𝑛2 ).
 Algorithm # 2 has complexity O(𝑛(𝑛 ∗ 𝑑)).
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Windows 7 Driver
 Communicates touch
coordinates to
operating system
 Dependent on image
processing
 Main focus for the
spring semester
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Calibration
 Adjust the size of projected
screen
 Touch four corners to define the
screen boundary
 Map image coordinates to
projected coordinates
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Infrared Emitting Pens
Components:
• Switch
• Infrared LED
• 120Ω Resistor
• AAA Battery
Electrical and Computer Engineering
Battery Life:
• Capacity of 1000 mAh
• 3.1 mA drawn by pen
• Life: 322.5 hours
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Physical Assembly
• Stable base supports
projector and camera at a
height up to 3.5’
• Designed to support
adjustable heights for
projector and camera
• Handle for portability
• Top opens for storage
Electrical and Computer Engineering
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Midway Design Review Goals
 Choose detection method
• IR emitting pens
 Position of projector and camera
• In front and above
 Use camera to detect infrared light
• Camera with IR longpass filter
 Extract coordinates of touch locations
• Image processing algorithms
Electrical and Computer Engineering
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What’s Next?
 Determine whether or not a dedicated signal
processing chip is necessary
 Windows 7 driver
 System calibration
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Updated Gantt Chart
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Conclusion
 Met all midway design review goals
 On track to complete L3PT by scheduled deadline
DEMO
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