25-02-2011, 10:49 AM
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MULTI TOUCH SCREENS
Abstract
The way we use computers today will soon change. The technology of the future will allow us to interact with the computer on a whole different level from what we are used to. The tools we use to communicate with the computer – such as the mouse and the keyboard, will soon disappear and be replaced with tools more comfortable and more natural for the human being to use. That future is already here. This report describes about the multi touch technology and their applications.
The increase rate of how touch screen hardware and applications are used is growing rapidly and will break new grounds in years to come. This new technology requires new ways for detecting inputs from the user – inputs which will be made out of onscreen gestures rather than by pressing of buttons or rolling mouse wheels.
The traditional way of interacting with a computer is by using a mouse or a key board. We provide the computer with inputs more or less by the use of buttons. Regardless of the input type, the computer can more or less only handle one input at the time which makes the input handling and sorting very easy.
However, multi touch is as far from single input handling as one can come. The amount of concurrent events in this interface is limited only by the data type holding the number of finger inputs. The amount of simultaneous users is pretty much unlimited in the same way, which of course in handy for larger scale display systems. That amount of potential synchronous inputs requires new ways to detect the inputs. Since they aren’t the kind of “on/off” inputs we are used in a traditional sense, they are needs for new ways interpret and analyze the input type and gesture(s) they make out.
For an example of where using more than one button or device at a time is important in the physical world, just think of having to type without being able to push the SHIFT key at the same time as the character that you want to appear in upper case. There are a number of cases where this can be of use in touch interfaces.
History
Multi-touch technology dates back to 1982, when Nimish Mehta at the UNIVERSITY OF TORONTO developed the first finger pressure multi-touch display.
In 1983, Bell labs at Murray hill published a comprehensive discussion of touch-screen based interfaces. In 1984 Bell Labs engineered a touch screen that could change images with more than one hand. The group at the University of Toronto stopped working on hardware and moved on to software and interfaces, expecting that they would have access to the Bell Labs work.
A breakthrough occurred in 1991, when Pierre Wellner published a paper on his multi-touch “Digital Desk”, which supported multi-finger and pinching motions.
Various companies expanded upon these discoveries in the beginning of the twenty-first century. Mainstream exposure to multi-touch technology occurred in the year 2007, when Apple unveiled the iPhone and Microsoft debuted surface computing. The iPhone in particular has spawned a wave of interest in multi-touch computing, since it permits greatly increased user interaction on a small scale. More robust and customizable multi-touch and gesture-based solutions are beginning to become available, among them True Touch, created by Cypress semiconductor. The use of multi-touch technology is expected to rapidly become common place. For example, touch screen telephones are expected to increase from 200,000 shipped in 2006, to 21 million in 2012.
Introduction
Touch screen
All of the touch screens basically work like a mouse. Once the software driver for the touch screen is installed, the touch screen emulates mouse functions. Touching the screen is basically the same as clicking your mouse at the same point at the screen. When you touch the touch screen, the mouse cursor will move to that point and make a mouse click. You can tap the screen twice to perform a double click, and you can also drag your finger across the touch screen to perform drag-and-drops. The touch screens will normally emulate left mouse clicks. Through software, you can also switch the touch screen to perform right mouse clicks instead.
Multi touch screen
Multi-touch consists of a touch screen (screen, overlay, table, wall, etc.) or touchpad, as well as software that recognizes multiple simultaneous touch points, as opposed to the single touch screen (e.g. computer touchpad, ATM), which recognizes only one touch point. This effect is achieved through a variety of means, including: heat, finger pressure, high capture rate cameras, infrared light, optic capture, tuned electromagnetic induction, ultrasonic receivers, transducer microphones, laser rangefinders, and shadow capture.