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Augmented Reality
Man makes robot intelligent
What is Augmented Reality?
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.
What is the Goal of AR?
To enhance a person’s performance and perception of the world
But, what is the ultimate goal????
The Ultimate Goal of AR
Create a system such that no user CANNOT tell the difference between the real world and the virtual augmentation of it.
Augmented Reality vs.Virtual Reality
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
Virtual Reality:
Totally immersive environment
Visual senses are under control of system (sometimes aural and proprioceptive senses too)
Miligram’s Reality-Virtuality Continuum
Miligram’s Taxonomy for Mixed Reality Displays
Reproduction Fidelity – quality of computer generated imagery
Extent of Presence Metaphor – level of immersion of the user within the displayed scene
Extent of World Knowledge – knowledge of relationship between frames of reference for the real world, the camera viewing it, and the user
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
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
Realistic Merging
Requires:
Objects to behave in physically plausible manners when manipulated
Occlusion
Collision detection
Shadows
**All of this requires a very detailed description of the physical scene
Components of an Augmented Reality System
Research Activities
Develop methods to register the two distinct sets of images and keep them registered in real-time
New work in this area has started to use computer vision techniques
Develop new display technologies for merging the two images
Performance Issues
Augmented Reality systems are expected:
To run in real-time so that the user can move around freely in the environment
Show a properly rendered augmented image
Therefore, 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
Limitations for Updating the Generated Images
Must be at 10 times/second
More photorealistic graphics rendering
Current technology does not support fully lit, shaded and ray-traced images of complex scenes
Failures in Registration
Failures in registration due to:
Noise
Position and pose of camera with respect to the real scene
Fluctuations of values while the system is running
Time delays
In calculating the camera position
In calculating the correct alignment of the graphics camera
Display Technologies
Monitor Based
Head Mounted Displays:
Video see-through
Optical see-through
Monitor Based Augmented Reality
Simplest available
Little feeling of being immersed in environment
Optical see-through HMD
Video see-through HMD
Video Composition for Video see-through HMD
Chroma-keying
Used for special effects
Background of computer graphics images is set to a specific color
Combining step replaces all colored areas with corresponding parts from video
Depth Information
Combine real and virtual images by a pixel-by-pixel depth comparison
Advantages of Video see-through HMD
Flexibility in composition strategies
Wide field of view
Real and virtual view delays can be matched
Advantages of Optical see-through HMD
Simplicity
Resolution
No eye offset
Applications
Medical
Entertainment
Military Training
Engineering Design
Robotics and Telerobotics
Manufacturing, Maintenance, and Repair
Consumer Design
Hazard Detection
Audio