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L3PT. Large Portable Projected Peripheral Touchscreen Team Jackson Brian Gosselin Greg Langlois Nick Jacek Dmitry Kovalenkov. Midway Design Review. ing. Project Overview. Portable Large workspace Affordable Single / Multi user Multi touch capabilities
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L3PT Large Portable Projected Peripheral Touchscreen Team Jackson Brian Gosselin Greg Langlois Nick Jacek Dmitry Kovalenkov Midway Design Review ing
Project Overview • Portable • Large workspace • Affordable • Single / Multi user • Multi touch capabilities • No other product currently on the market meets all these specifications.
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.
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.
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
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
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
Speed Of Image Processing • Algorithm # 1 has complexity O(). • Algorithm # 2 has complexity O().
Windows 7 Driver • Communicates touch coordinates to operating system • Dependent on image processing • Main focus for the spring semester
Calibration • Adjust the size of projected screen • Touch four corners to define the screen boundary • Map image coordinates to projected coordinates
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
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
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
What’s Next? • Determine whether or not a dedicated signal processing chip is necessary • Windows 7 driver • System calibration
Conclusion • Met all midway design review goals • On track to complete L3PT by scheduled deadline DEMO