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