1. Online Handwriting Recognition
Charles C. Tappert
School of Computer Science and Information Systems
Pace University

2. Handwriting Recognition
Offline
Scanned Images
Static Information
Online
Electronic Tablet or Digitizer
Real-Time, Dynamic Information

3. Online Handwriting Recognition
Invention of electronic tablets -- late 1950s
Tablet and display were separate
Pen Computing s
Combined tablets and display
Brought input and output into the same surface
Immediate feedback via electronic link
Created the paper-like interface

4. A person using a Rand Tablet

5. Pen Computing
Pen computer – a notebook/handheld computer with a stylus-based user interface
Paper-like interface – executes job-specific applications by emulation of paper-based work methods
Wireless communication – portable extension of the corporate Information System, extending not only through the corporate plant but also into its customer’s offices
The computer goes where the work is

6. Pen Computing

7. Tablet Digitizer – Dynamic Information
Pen Down – indication of inking
X-Y coordinates
Resolution: 200 points/inch
Sampling rate: 100 points/second

8. Dynamic Handwriting Information
Number of Strokes
a stroke is the ink trace from pen down to pen up
Order of strokes
Stroke Direction
Stroke velocity, acceleration

9. Written Language and Handwriting Properties
Alphabet
Letters, digits, punctuation, special symbols
Writing is a time sequence of strokes
Complete one character before beginning next except for delayed strokes
Spatial order – for example, left to right.

10. Fundamental Property of Writing
Differences between different characters are more significant than differences between drawings of the same character
This is what makes written communication possible
Possible exceptions

11. Written English Writing Styles
Handwriting
Uppercase – about 2 strokes per letter
Lowercase – about 1 stroke per letter
Cursive Script
Less than a stroke per letter
Delayed crossing and dotting of strokes

12. Many Computer Recognition Problems
Various Language Alphabets
Shorthand – for example, Pitman
Spreadsheets
Flowcharts
Line Drawings
Editing Symbols for text editing

13. Computer Problems in English
Constrained Handprint
Printing on lines – symbols can touch/overlap
Printing one symbol per box – form filling
Unconstrained Handprint
No lines and symbols can touch or overlap
Cursive Script
Mixed Printing and Cursive

14. Handprint Recognition Difficulties
Digitizer problems
Writing variation not handheld by system
Uppercase versus lowercase versus digits
Segmentation – character within character problem

15. History of Computer Systems for English Printing
System Handled only Specified Variations
Small number of variations per symbol
All common variations
System Trained to User
Usually with built in prototypes covering common variations

16. Survey Journal Article in 1990 44 Systems, 300 References
11 Experimental Systems for Handprint
4 Experimental Systems for Cursive Script
16 Commercial Systems for Opaque Tablets
5 Commercial Systems for Pen Computers
8 Experimental Application Systems
(Spreadsheets, flowcharts, etc.)

17. Example Systems Rand System 1966 – Groner
Pencept Commercial Product 1980s
ATT System 1983 – Don Burr
IBM Runon System 1984 – Chuck Tappert
Linus Commercial Product 1987 –
Ralph Sklarew

18. A person using a Rand Tablet

19. Pencept Product – Pairwise Discrimination

21. Tappert System

22. Combined Characters Segmentation and Recognition

23. Categories of Systems University Project Systems – least robust
Industrial Project Systems – more robust
Commercial Products – most robust
Fred Brooks’ Mythical Man Month
program – programming system – programming systems product

24. Conclusion and Future Work
Graffiti recognizer greatly simplified the recognition problem
Handprint problem not completely solved
Even with IBM’s ThinkWrite and CIC’s Jot products
Cursive script not solved

25. Context Essential
Other Low Performance Characters