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Augmented Reality

Augmented Reality. David Johnson. What Is Augmented Reality (AR)?. A combination of a real scene viewed by a user and a virtual scene generated by a computer that augments the scene with additional information. ARToolkit demo movie T-immersion 2004 video. Augmented Reality

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Augmented Reality

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  1. Augmented Reality David Johnson

  2. What Is Augmented Reality (AR)? • A combination of • a real scene viewed by a user and • a virtual scene generated by a computer that augments the scene with additional information. • ARToolkit demo movie • T-immersion 2004 video

  3. Augmented Reality System augments the real world scene User maintains a sense of presence in real world Needs a mechanism to combine virtual and real worlds Hard to register real and virtual Virtual Reality Totally immersive environment Senses are under control of system Need a mechanism to feed virtual world to user Hard to make VR world interesting Augmented Reality vs. Virtual Reality

  4. Milgram’s Reality-Virtuality Continuum Mixed Reality (MR) Real Environment Augmented Reality (AR) Virtual Environment Augmented Virtuality (AV) Milgram coined the term “Augmented Virtuality” to identify systems which are mostly synthetic with some real world imagery added such as texture mapping video onto virtual objects.

  5. Combining the Real and Virtual Worlds We need: • Precise models • Locations and optical properties of the viewer (or camera) and the display • Calibration of all devices • To combine all local coordinate systems centered on the devices and the objects in the scene in a global coordinate system

  6. Combining the Real and Virtual Worlds (cont) • Register models of all 3D objects of interest with their counterparts in the scene • Track the objects over time when the user moves and interacts with the scene

  7. Realistic Merging Requires: • Objects to behave in physically plausible manners when manipulated • Occlusion • Collision detection • Shadows

  8. Research Activities • Develop methods to register the two distinct sets (real, virtual) of images and keep them registered in real-time • This often reduces to finding the position of a camera relative to some fiducial markers • Develop new display technologies for merging the two images

  9. Performance Issues Two performance criteria are placed on the system: • Update rate for generating the augmenting image • Accuracy of the registration of the real and virtual image • Update rate can limit registration accuracy as well • Brooks paper – “1 ms = 1mm error”

  10. Failures in Registration Failures in registration due to: • Noise • Position and pose of camera with respect to the real scene • Image distortions • Time delays • In calculating the camera position

  11. Display Technologies • Monitor Based • Laptops • Cell phones • Projectors (more Ubiquitous Computing) • Head Mounted Displays: • Video see-through • Optical see-through

  12. Monitor Based Augmented Reality • Simplest available • Treat laptop/PDA/cell phone as a window through which you can see AR world. • Sunglasses demo

  13. Monitor Based AR • Successful commercialization • Yellow line in football broadcasts • Glowing hockey puck • Replace times square billboards with own commercials during New Year’s Eve broadcasts • Baseball cards • Ad campaigns

  14. Optical see-through HMD

  15. Video see-through HMD

  16. Advantages of Video see-through HMD • Flexibility in composition strategies • Real and virtual view delays can be matched

  17. Advantages of Optical see-through HMD • Simplicity • Resolution • No eye offset

  18. Advantage of Monitor Displays • Consumer-level equipment • Most practical • A lot of current research aimed here • Other current active area is a flip-down optical display.

  19. Early Application • KARMA (91) • Feiner • Optical see-through HMD • Knowledge-based assistant for maintenance • Ultrasound trackers attached to assembly parts

  20. Early Application • Later – “architectural anatomy” - movie • Tourguide - movie

  21. More Mechanical • ECRC

  22. UNC - Medical • Early 90’s • Lots of work on reducing registration error • Explain movie • Teapot movie • Medical applications • movie

  23. MIT Medical • Laser-scanned patient • LCD screen above patient

  24. AR Instructional • Reality provides a natural interface • MagicBook movie

  25. AR Games • ARQuake

  26. AR • Lots of new applications • Will discuss some tracking systems next class

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