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Touchscreen%20 implementation%20for%20multi touch-new[1] (1)
This document discusses surface computing and multi-touch display devices. Surface computing allows users to interact directly with a touch-sensitive screen instead of using a keyboard and mouse. Multi-touch devices allow multiple touches at once, serving as a substitute for traditional input devices. The document then describes various touchscreen technologies like resistive and capacitive, how they work, their advantages and disadvantages. It also covers implementation of gesture recognition software to interpret user inputs on touchscreens. Finally, potential applications of these technologies are mentioned.
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- 4. Introduction Surface computingis the term for the use of a specialized computer GUI in which traditional GUI elements are replaced by intuitive, everyday objects. Instead of a keyboard and mouse, the user interacts directly with a touch- sensitive screen.
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- 6. Description The multi-touchdevice is a user interface device that will allow a user to interact with a computer through use of a multi-touch display. Thus, it is a substitute to the keyboard and mouse. In this user can directly interact with the system with their fingers and not only this but with multiple touches at the same instant.
- 7. A basictouch-screen has three main components: 1. Touch sensor; 2. Controller; 3. Software driver. The touch-screen is an input device, so it needs to be combined with a display and a PC or other device to make a complete touch input system. How Does a Touchscreen Work?
- 8. Touchscreen Technologies Resistive Capacitive Surface Projected Optical imaging FTIR DI DSI
- 9. Resistive Touchscreen Composedof multiple layers separated by thin spaces Using indium tin oxide (ITO) layers Different standards 4, 5, and 8 wire types Each have advantages
- 10. Resistive Touchscreen UserPresses Down Contact is Made Uniform Voltage on First Screen for X Same on Second screen for Y Happens instantaneously
- 11. 4-Wire design Onescreen for X Another screen for Y Both create voltage gradient. Uses voltage divider
- 12. Advantages & Disadvantages Works well with fingertip or stylus input Generally most affordable touchscreen technology Rugged/Durable Has multi-touch input capabilities Not as accurate Multi-touch much more complex Usually no discretion between stylus and hand More pressure needed
- 13. Capacitive Touch Technology Consists of: Insulator (glass or Air) Conductive coating (ITO) Two types: Surface projected
- 14. Surface Capacitance Onlyone side is coated Electrodes at the edges Distribute voltage
- 15. Capacitor forms Current flows Determine location Controller Ratio of currents , XY coordinates A R ρ× = 1 αi R Surface Capacitance
- 16. Projected Capacitance Twoparallel ITO(Indium Tin Oxide ) layers Two sheets of glass
- 17. Projected Capacitance EField is projected through glass Finger couples with E field Capacitance changes Capacitor at each point on the surface
- 18. Surface vs. Projected Limited resolution Single touch Operation with direct contact High resolution Multi touch Operation with indirect contact
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- 20. Frustrated Total InternalReflectionFrustrated Total Internal Reflection A process by which light is trapped within a medium and can be interrupted by a third medium of higher reflective index to cause light to escape.
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- 24. Software Surface Capture viaDetector Digitized View
- 25. Software Cont. Interpretand Relay Information Assign Objects or gestures with Unique ID# and location Compare and Execute Digitized Object Application ProtocolRaw Data Feedback to User
- 26. Universal DesignPrinciples Utility for all users Simple and intuitive Touchscreens depend on visual feedback in order to use Improving Accessibility?
- 27. Cursor movementsas command shortcuts Takes place of keyboard shortcuts Useful in applications where keyboard use is less prominent or undesirable Pointing Device Gestures Above: Some possible cursor movement patterns for use in gesture support.
- 28. Implementation: Step 1 Filter Input Sampling rate Smooth out input data, get rid of unnecessary “noise” Simplify data analysis
- 29. Implementation: Step 2 Vectorize Separate x- and y-component Compute dominant component and ignore smaller one Store in array
- 30. Implementation: Step 3 Matching Match captured vector array to pre-defined gesture library If no match, pop smallest vector from array and repeat matching process
- 31. Example Fig. 1 –User input Fig. 2 – Captured/filtered pointer data Fig. 3 – After vectorization Fig. 4 – Final matching result
- 32. Allows fora quicker and more efficient UI Universal Design Enhances usability for visually-impaired as well as non-impaired Easily added to existing touchscreen devices, no additional hardware required Goal
- 33. A personalcomputerwith 20 GBfree hard disk space, 1GBRAMand PIV + processorcan be efficient enough. The Windows Vista operating systemwas chosen because the CCV package is highly supported in Windows. Computer Subsystem
- 34. Many differentplatforms can be used to develop multi-touch applications utilizing TUIO events. Such platforms include: Adobe Flash Java C++ Python Application Development
- 35. Personal Computing Graphics Audio Mixing Video Playing ComputerGaming Slide Presentations ……and many more! APPLICATIONS
Editor's Notes
- #2 Introductions