Dialog Design 3 How to use a PDA Fall 2002 CS/PSY 6750

Personal Digital Asst. (PDA) Palm VII Palm IIIc Handspring Visor HP Jornada Apple Newton (1993) Fall 2002 CS/PSY 6750

PDAs Becoming more common and widely used Smaller display (160x160), (320x240) Few buttons, interact through pen Estimate: 14 million shipped by 2004 Improvements Wireless, color, more memory, better CPU, better OS Palmtop versus Handheld Fall 2002 CS/PSY 6750

No Shredder… Fall 2002 CS/PSY 6750

Input Pen is dominant form Three main techniques Free-form ink Soft keyboards (tapping) Recognition systems Also can connect keyboard Fall 2002 CS/PSY 6750

Free-form Ink Ink is the data, take as is Human is responsible for understanding and interpretation Like a sketch pad Example Digital Ink - CMU video, CHI ‘98 Flatland - Xerox PARC video, CHI ‘99 Fall 2002 CS/PSY 6750

Soft Keyboards Common on PDAs and mobile devices Many varieties Tapping interface Stroking interface Fall 2002 CS/PSY 6750

Tapping Interface Presents a small diagram of keyboard You click on buttons/keys with pen QWERTY vs. alphabetical Tradeoffs? Alternatives? Fall 2002 CS/PSY 6750

Tegic Communications-T9 Tapping interface that uses phone pad You press out letters of your word, it matches the most likely word, then gives optional choices Used in mobile phones www.tegic.com/t9 Fall 2002 CS/PSY 6750

Cirrin Developed by Jen Mankoff (GT->Cal) Word-level unistroke technique Fall 2002 CS/PSY 6750

Recognition Systems Handwriting Recognition Recognizing letters and numbers Special symbols Handwriting Recognition Lots of systems (commercial too) English, kanji, etc. Not perfect, but people aren’t either! People - 96% handprinted single characters Computer - >97% is really good OCR (Optical Character Recognition) Fall 2002 CS/PSY 6750

Recognition Issues Off-line vs. On-line Bitmapped vs. Vectorized Off-line: After all writing is done, speed not an issue, only quality On-line: Must respond in real-time Bitmapped vs. Vectorized Bitmapped: Usually off-line, like OCR Vectorized: On-line, uses angle, direction, speed, pressure, acceleration, etc. Fall 2002 CS/PSY 6750

More Issues Boxed vs. Free-Form input Printed vs. Cursive Sometimes encounter boxes on forms Printed vs. Cursive Cursive is much more difficult Letters vs. Words Cursive is easier to do words Using context & words can help Usually requires existence of a dictionary Check to see if word exists Consider 1/I/l Training - Many systems improve a lot with training data Fall 2002 CS/PSY 6750

Special Alphabets Graffiti - Unistroke alphabet on Palm PDA Experience? Other alphabets or purposes Gestures for commands Fall 2002 CS/PSY 6750

Pen Gesture Commands - Might mean delete Define a series of (hopefully) simple drawing gestures that mean different commands in a system Fall 2002 CS/PSY 6750

Pen Use Modes Often, want a mix of free-form drawing and special commands Might use visible mode switch Might have pen action buttons/switches Fall 2002 CS/PSY 6750

Error Correction Having to correct errors can slow input tremendously Strategies Erase and try again n-best list ... Fall 2002 CS/PSY 6750

Interesting Applications Signature verification Note-taking Academic course Corporate meeting Sketching systems Designers’ aids Example Silk - J. Landay, CMU Video, CHI ‘96 Fall 2002 CS/PSY 6750