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Garrivier & Bossis, 2005). In order to facilitate
the recognition process, we used a unistroke
alphabet, but we just changed the symbols that
cannot be draw with only one gesture. The goal
was to keep gestures as close as possible to the
classical ones in order to make a more user-friendly
and more usable system and to limit as much as
possible the rupture in the creation process. For
instance, a durational dot is drawn as a small
dot on the right of a note head; an accidental is
drawn close to a note head on its left: a flat is
drawn with one stroke the same way as on paper,
but the gestures for the sharp and the natural are
changed, for a horizontal segment and a vertical
segment respectively. We also proposed differ-
ent gestures for a same symbol when it seemed
appropriate. Thus, a filled-note head can be done
in several ways, for instance by drawing a dot, a
slash, a scribble, and so forth. The originality of
our approach was to exploit the structural context
of a stroke to interpret it. For example, a stroke
drawn close to a note head on its left has a high
probability of being an accidental; then, instead
of trying to recognize any possible symbol, we
try to recognize an accidental. Actually, we kept
some of the concepts of this system to design the
generic approach we present in the continuation of
this chapter. The fourth column of Table 1 presents
some of the gestures of this system.
In 2004, Miyao and Maruyama, and then
Mitobe, Miyao, and Maruyama, presented an
online musical score recognition system, which
is able to deal with multistroke symbols. As far
as we know, with the exception of the work we
present in this chapter, there is no other system
with such a capability. The gestures they propose
are almost the same as the classical one, with
one exception (a filled-note head is drawn with
a circle with a slash in order to reduce the input
time). The analysis process consists then in two
steps. In the first one, each user stroke is inter-
preted as a primitive form, that is as one of the
unitary symbols that can exist in musical scores:
they are all the unistroke symbols (whole-notes,
half-notes, clefs, flat, etc.) and all the components
of the multistroke ones (horizontal and vertical
segments, which can be part of a sharp, etc.). In
the second step, the system tries to combine the
primitive forms to produce multistroke elements.
Although the system they present does not propose
enough available symbols to be usable, we believe
that their approach is interesting. Actually, some
of the concepts we present in the following sec-
tion are close to some of these authors. The fifth
column of Table 1 presents some of the gestures
of this system.
In the next section, we introduce the generic
approach we designed to develop pen-based
structured document composition and editing
software. We have in particular exploited this
approach to develop a system for classical musi-
cal score notations, which aims at letting the user
Figure 4. Screenshots of the pen-based musical score editor developed with the presented methodology:
On the left, the user draws a beam between two quarter-notes, and on the right it is replaced by its neatly
re-transcribed symbol thanks to an eager interpretation process
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