arpad kovacs cs260 class discussion cs260 - input ii...

Arpad Kovacs CS260 Class Discussion

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CS260 - Input II: Surface ComputingArpad Kovacs, 2010.09.15


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What is Surface Computing?

Replace monitor, mouse and keyboard with intuitive objects and touch-based interactions

Why?

Computers

CalculationCut-and-pasteSpell-checking

Search

Physical Objects

Direct ManipulationTactile Feedback

FamiliarityKinesthetic Memory


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Interacting with Paperon the Digital Desk

Pierre Wellner at Xerox EuroPARC, 1993● 1st system of its kind (computer vision, multitouch)● Seamless integration of computation and paper● New methods of interaction (tracing, data copying)● Collaboration via DoubleDigitalDesk and voicelink


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Digital Desk Impact andModern Descendents

- Still have paper, scanners, photocopiers- What about PDF/XPS?

Paperless Office vs Paper-Integrated Office

Technological Advancements

Remaining Unsolved Issues

- High-res cameras, better computer vision- Capacitive/Resistive touchscreen technology

- Midas Touch (unintentional input)- Occlusion (“fat-finger” problem)


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Low-Cost Multi-Touch Sensing thruFrustrated Total Internal Reflection

Jeff Han at NYU Media Research Laboratory, 2005

Conventional multitouch devices- Matrix of sensors has limited resolution- Complicated/costly to build: lots of connections- Opaque (only overhead projection onto surface feasible)+ Durable/reliable?

Infrared Video cameras+ High resolution+ Cheap- Prone to interference, noisy signal- Need space behind screen


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Optics Review

Snell's Law – light bends due to Δ index of refraction

at material boundaries

n=cv=

speed of light in vacuumspeed of light in medium

n2n1

Index of Refractionspeed at which light can travel through a medium


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Frustrated Total Internal Reflection

Total Internal ReflectionIf n

A >> n

B, bending of light

exceeds critical angle ΘC, light

cannot escape the medium A

Frustrated TIRA 3rd material with n

C > n

B can

alter refraction characteristicsand allow light to escape.


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Implementation1) A sheet of acrylic is lighted from its edges using infrared LEDs2) Infrared camera is placed orthogonal to the surface3) Upon touching the surface, light scatters due to frustrated total Internal reflection


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Additional Possibilities

What additional interactions could be implemented using this technology, and how??

- Hover (via holographic screen or stereo camera)- Detect multiple users- 3D structure from motion


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Additional Questions /Comments / Discussion

When might surface computing be a bad idea?

Multitouch interface learning curve / Ease of use

Future evolution of surface computing


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Image Credits and Attribution

Scientific Americanhttp://www.scientificamerican.com/article.cfm?

id=how-it-works-touch-surfaces-explained

Wikipediahttps://secure.wikimedia.org/wikipedia/en/wiki/

Snell's_Law

http://www.scientificamerican.com/article.cfm

https://secure.wikimedia.org/wikipedia/en/wiki/

arpad kovacs cs260 class discussion cs260 - input ii...

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