Browse Prior Art Database

Improved Direction Angle Parameter Reduces the Effect of Hooks in Online Handwriting Recognition

IP.com Disclosure Number: IPCOM000121248D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Tappert, CC: AUTHOR

Abstract

Many online handwriting recognition systems use elastic curve matching to match an unknown character against prototype (template) characters (1). The accuracy of these recognizers depends on the distance metric and the parameters (measurements) used in matching.

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Improved Direction Angle Parameter Reduces the Effect of Hooks in
Online Handwriting Recognition

      Many online handwriting recognition systems use elastic
curve matching to match an unknown character against prototype
(template) characters (1). The accuracy of these recognizers depends
on the distance metric and the parameters (measurements) used in
matching.

      Writing with a special stylus on an electronic tablet is not
quite like writing with pen or pencil on paper.  For the early
electronic tablets, the stylus was usually equipped with a ball point
pen so that by mounting a piece of paper on the tablet one saw the
ink appear on the paper while writing.  For the modern tablet
digitizers one is usually writing on the surface of a tablet-display
and the trace of the tip of the writing stylus appears on the display
as one writes.  The correspondence between the ink traces on the
paper or display and the data points electronically recorded,
however, is not always precise. Apart from inaccuracies due to tablet
resolution and sampling rate, the most prevalent inaccuracy is
usually that of extra data recorded having the appearance of "hooks".
A hook can occur at the beginning but more usually at the end of a
stroke and is due to inaccuracy of pen up-down detection in the
hardware.  A method previously disclosed (2) tried to eliminate
extraneous hooks for both display and recognition of handwriting.
Because hooks are difficult to detect that method sometimes
mistakenly eliminated non-hooks that were important for character
recognition.

      Disclosed here is an improved direction-angle parameter that
reduces the effect of hooks without eliminating the hooks themselves.
In our handwriting recognizer a stroke (the writing from pen...