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Modeling simple and complex handwriting based on EMG signals 137

8 0.35

IEMG(CH1) 6 4 0.3

0.25
2

0.15
0 0.2
0 0.5 1 1.5 2 2.5 3 3.5 4
10 0.4
IEMG(CH2) 5 0.2

0 0
0 0.5 1 1.5 2 2.5 3 3.5 4
Time (s)
Fig. 4 Traces of data recorded during the experiment showing the integrated EMG in
blue (gray in print version).

particular by the presence of tremor (Meulenbroek and Thomassen, 1991).
The writer being right-handed or left-handed can cause systematic errors
toward the nearest preferential orientation, which affects the production
of the graphical form.
Participants in the experiment are accustomed to producing Japanese
writing systems, having a direction of progression from left to right, which
is different from Arab systems. In this experiment, participants wrote Arabic
letters, which inevitably influenced the speed and preferential direction of
the writers. The production of geometric shapes is faster.
In this context, Meunlenbroek has also shown that the generation of ver-
tical lines is faster than horizontal lines as are the movements from top to
bottom, which are also more accurate than the movements from bottom
to top (Dinh et al., 2014).
ﻉ
These writers wrote three cursive Arabic letters ( ﺱ ﺡ , ) and drew eight
,
basic geometric shapes as shown in Table 2. Fig. 5 presents the recorded data
for the Arabic letter “AIN.”