Electrical and Computer Engineer
Large Portable Projected PeripheralTouchscreen
Team JacksonBrian GosselinGreg Langlois
Nick JacekDmitry Kovalenkov
L3PT
Midway Design Review
ing
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Project Overview
• Portable• Large workspace• Affordable• Single / Multi user• Multi touch capabilities
No other product currently on the market meets all these specifications.
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System Block Diagram
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MicroVision SHOWWX Laser Pico Projector
• 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.
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Microsoft LifeCam vx-2000
• 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.
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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
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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
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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(). Algorithm # 2 has complexity O().
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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
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
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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
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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