Pen computing

Pen computing refers to a computer user-interface computer using a pen (or stylus) and tablet, rather than devices such as a keyboard and a mouse.

Pen computing is also used to refer to the usage of mobile devices such as wireless tablet PCs, PDAs and GPS receivers. The term has been used to refer to the usage of any product allowing for mobile communication. An indication of such a device is a stylus, generally used to press upon a graphics tablet or touchscreen, as opposed to using a more traditional interface such as a keyboard, keypad, mouse or touchpad.

Historically, pen computing (defined as pointing device plus handwriting recognition) predates the use of a mouse and graphical display by at least two decades, starting with the Stylator ^[1] and RAND tablet^[2] systems of the 1950s and early 1960s.

General techniques of pen computing

User interfaces for Pen computing can be implemented in several ways. Actual systems generally employ a combination of these techniques.

Pointing/Locator input

The tablet and stylus are used as pointing devices, such as to replace a mouse. Note that a mouse is a

relative pointing device -- you use the mouse to "push the cursor around" on a screen.

However a tablet is an

absolute pointing device -- where you put the stylus is exactly where the cursor goes.

There are a number of human factors considerations when actually substituting a stylus and tablet for a mouse. For example, it is much harder to target or tap the same exact position twice with a stylus, so "double-tap" operations with a stylus are harder to perform if the system is expecting "double-click" input from a mouse.

Note that a finger can be used as the stylus on a touch-sensitive tablet surface, such as with a touchscreen.

Handwriting recognition

The tablet and stylus can be used to replace both a mouse and a keyboard, by using the tablet and stylus in two modes:

Pointing mode: The stylus is used as a pointing device as above.
Handwriting recognition mode: The strokes made with the stylus are analyzed as a "electronic ink", by software which recognizes the shapes of the strokes or marks as handwritten characters. The characters are then input as text, as if from a keyboard.

Different systems switch between the modes (pointing vs. handwriting recognition) by different means, e.g.

by writing in separate areas of the tablet for pointing mode and for handwriting-recognition mode.
by pressing a special button on the side of the stylus to change modes.
by context, such as treating any marks not recognized as text as pointing input.
by recognizing a special gesture mark.

Direct manipulation

The stylus is used to touch, press, and drag on simulated objects directly. See the special Wiki article on Direct manipulation. The Wang Freestyle system ^[3] is one example. Freestyle worked entirely by direct manipulation, with the addition of electronic "ink" for adding handwritten notes.

Gesture recognition

This is the technique of recognizing certain special shapes not as handwriting input, but as an indicator of a special command.

For example, a "pig-tail" shape (used often as a proofreader's mark) would indicate a "delete" operation. Depending on the implementation, what is deleted might be the object or text where the mark was made, or the stylus can be used as a pointing device to select what it is that should be deleted.

Recent systems have used digitizers which can recognize more than one "stylus" (usually a finger) at a time, and make use of Multi-touch gestures.

The PenPoint OS was a special operating system which incorporated gesture recognition and handwriting input at all levels of the operating system. Prior systems which employed gesture recognition only did so within special applications, such as CAD/CAM applications ^[4] ^[5]or text processing.^[6]

References

^ Dimond, T.L. (1957-12-01), Devices for reading handwritten characters, Proceedings of Eastern Joint Computer Conference, pp. 232–237
^ Groner, G.F. (1966-08), Real-Time Recognition of Handprinted Text, Memorandum RM-5016-ARPA, RAND Corporation {{citation}}: Check date values in: |date= (help)
^ WANG Freestyle demo, Wang Laboratories, 1989, retrieved 2008-09-22
^ Computerized Graphic Processing System: System User's Manual, Applicon Incorporated, 1973-09-01
^ Newman, W.M. (1973-09-01), The Ledeen Character Recognizer, Principles of Interactive Computer Graphics, McGraw-Hill, pp. 575–582
^ Coleman, Michael L. (1969), Text editing on a graphic display device using hand-drawn proofreader's symbols, from Pertinent Concepts in Computer Graphics: Proceedings of the 2nd University of Illinois Conference on Computer Graphics, University of Illinois Press

External links

The Unknown History of Pen Computing contains a history of pen computing from approximately 1917 to 1992.
Annotated bibliography of references to handwriting recognition and pen computing
A number of links to pen computing resources