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Shorthand Handwriting Recognition for Pen-Centric Interfaces Charles C. Tappert 1 and Jean R. Ward 2 1 School of CSIS, Pace University, New York, USA 2 Pen Computing Consultant, Massachusetts, USA Will provide critical infrastructure for many pen-centric applications

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shorthand handwriting recognition for pen centric interfaces

Shorthand Handwriting Recognition for Pen-Centric Interfaces

Charles C. Tappert1 and Jean R. Ward2

1 School of CSIS, Pace University, New York, USA

2 Pen Computing Consultant, Massachusetts, USA

thesis pen centric chatroom like shorthand interfaces
Will provide critical infrastructure for many pen-centric applications

Will provide fast text input

Will have greatest impact on applications running on small mobile devices

Thesis: Pen-Centric, Chatroom-Like Shorthand Interfaces
agenda
Handwriting

Fundamental Property of Writing

Handwriting Recognition Difficulties

Historical Shorthand Alphabets

Online(Pen-Centric) Handwriting Recognition

Onlinemore accurate than Offline Recognition

Online Info Can Complicate Recognition Process

Design Tradeoffs/Decisions

Pen-Centric Shorthand Alphabets

Pen-Centric Word/Phrase Shorthand

Allegro/Chatroom Experimental Shorthand System

Agenda
fundamental property of writing
Differences between different characters are more significant than differences between different drawings of the same character

This makes handwritten communication possible

Fundamental Property of Writing
fundamental property of writing5
Fundamental Property of Writing
  • Property holds within subalphabets of uppercase, lowercase, and digits, but not across them
  • “I”, “l”, and “1” written with single vertical stroke
  • “O” and “0” written similarly with an oval
handwriting recognition difficulties
Shape, size, and slant variation

Similarly shaped characters – U and V

Careless writing

in the extreme, almost illegible writing

Resolving difficult ambiguities requires sophisticated recognition algorithms, syntax/semantics

Handwriting Recognition Difficulties
historical shorthand alphabets prior to pen computing
Famous writings were written in shorthand

Cicero’s orations

Martin Luther’s sermons

Shakespeare’s and George Bernard Shaw’s plays

We focus on shorthand appropriate for PDAs

Two main types of shorthand

Non-geometric shorthand

Geometric shorthand

Small number of basic shapes

Shapes reused in multiple orientations

Historical Shorthand Alphabets(prior to pen computing)
stenographie alphabet 160210
Stenographie Alphabet, 1602

Geometric shorthand – basic shapes/orientations

moon alphabet 1894
Moon Alphabet, 1894
  • Geometric shorthand – basic shapes/orientations
other historical shorthand systems
Phonetic alphabets

Pitman (1837)

Gregg (1885)

Systems for the blind

Braille (1824)

Cursive shorthands

Gabelsberger (1834)

Other Historical Shorthand Systems
online pen centric handwriting recognition
Machine recognizes the writing as the user writes

Digitizer equipment captures the dynamic information of the writing

Stroke number,order,direction,speed

A stroke is the writing from pen down to pen up

Online(Pen-Centric) Handwriting Recognition
online pen centric more accurate than offline static recognition
Can use both dynamic and static information

Can often distinguish between similarly shaped characters

E.g., 5 versus S where the 5 is usually written with two strokes and the S with one stroke

Online(Pen-Centric) more accurate than Offline (Static) Recognition
online information can complicate recognition process
Online Information Can Complicate Recognition Process
  • Segmentation ambiguities
    • Character-within-character problem – cl versus d
  • Large number of possible variations
    • E can be written with one, two, three, or four strokes, and with various stroke orders and directions
    • Four-stroke E has 384 variations (4! stroke orders x 24 stroke directions)
design tradeoffs decisions
No constraints on the user

Machine recognizes user's normal writing

User severely constrained

Must write in particular style such as handprint

Must write strokes in particular order, direction, and graphical specification

Simplest is one stroke per character, one stroke direction, one shape

Design Tradeoffs/Decisions
pen centric shorthand alphabets
Some of the earliest were for CAD/CAM

Others developed for text input on PDAs

We review geometric and non-geometric shorthands appropriate for small devices

Historical alphabets presented above could be used for machine recognition

In addition to shape and orientation, stroke direction can differentiate among symbols

Pen-Centric Shorthand Alphabets
simplified design tradeoffs decisions for graffiti and allegro pda alphabets
Small alphabet

one case rather than both upper and lowercase

Small number of writing variations per letter

preferably only one

One stroke per character (character = stroke)

allows machine to recognize each character upon pen lift

Separate writing areas for letters and digits

avoids confusion of similarly shaped letters and digits

Simplified Design Tradeoffs/Decisions for Graffiti and Allegro PDA Alphabets
graffiti and allegro commercially successful shorthands
Graffiti and AllegroCommercially Successful Shorthands
  • High correspondence to Roman alphabet
    • Easier to learn
    • Graffiti used in Palm OS devices
      • notably the Palm Pilot and Handspring models
    • Allegro used in Microsoft Windows devices
  • Geometric alphabets not successful
pen centric word phrase shorthand e g chatroom shorthand
Pen-Centric Word/Phrase Shorthande.g., Chatroom Shorthand
  • Further increase speed of text entry
  • Potential applications
    • Where input speed important
    • Where word/phrase abbreviations occur frequently – e.g., email
allegro chatroom shorthand system
Allegro/Chatroom Shorthand System
  • Developed for M.S. dissertation
    • Student was hearing impaired
    • Developed as output component of communication system
      • Handwriting to text to speech
  • Two input writing areas
    • One for Allegro (all-purpose)
    • One for chatroom-like words/phrases (e.g., CUL, F2F)
allegro chatroom shorthand system preliminary experimental results
Allegro/Chatroom Shorthand SystemPreliminary Experimental Results
  • Allegro/Chatroom pen-centric shorthand input faster than typing text and comparable to typing text and chatroom shorthand characters
conclusions pen centric chatroom like shorthand interfaces
Will provide critical infrastructure for many pen-centric applications

Will provide fast text input

Will have greatest impact on applications running on small mobile devices

Conclusions: Pen-Centric, Chatroom-Like Shorthand Interfaces