DEVELOPMENT OF STEREOSCOPIC ALPHABET
LITERACY LEARNING SYSTEM FOR CHILDREN WITH
DEVELOPMENTAL DYSLEXIA
Hanae Yamazoe (Ikeshita), Takashi Kawai
Global Information and Telecommunication Institute, Waseda University
1011 Okuboyama, Nishi-Tomida, Honjo-shi, Saitama , 367-0035, Japan
Hitoshi Yamagata, Kazuhiro Niinuma, Yujiro Ono
NAMCO BANDAI Games Inc., 4-5-15 Higashishinagawa, Shinagawa-ku. Tokyo 140-0002, Japan
Masutomo Miyao
National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan
Keywords: Developmental Dyslexia, Depth-fused 3D, Literacy Learning, Stereoscopic Vision.
Abstract: A unique stereoscopic system has been developed to support intelligible understandings of alphabet
characters. The system is consisted of ordered pair of strokes with distinct depths, which might be useful to
help the learning for children with developmental dyslexia. We showed previously the effectiveness for
hiragana learning (Yamazoe et al. 2009), but not yet for the alphabet learning. Thus, we have evaluated a
literacy learning system with normal subjects in the present study. Clean advantages of stereoscopic
perceptual recognition over the flat recognition are obtained for alphabets as well as hiragana, suggesting
the effectiveness of stereoscopic learning, irrespective of dialogue characters.
1 INTRODUCTION
Developmental dyslexia is a specific learning
disability that is neurobiological in origin (Lyon et
al. 2003). It is a phonological deficit characterized
by difficulty distinguishing speech sounds
(phonemes) aurally and as represented in written
language. One of the deficits in children with
developmental dyslexia involves the ability to
analyze component phonemes of words, sometimes
referred to as phonemic awareness. Indiviuals with
developmental dyslexia in Japanese character have
recognition problems is decomposing characters into
their components, patterns, or strokes. Children with
developmental dyslexia often showed difficulties for
the understanding of the aggregated structure of
characters at the beginning of their writing. These
factors are believed to contribute to impeded acquire
literacy skills. In schools, literacy learning are
processed through two steps: students look a model
of character with guidance, and then followed the
shapes exactly. This school literacy learning method
may not be suitable for children with developmental
dyslexia. Thus literacy education materials had been
designed specific for children with developmental
dyslexia. Only planar materials such as paper and
flat displays are however, used at traditional literacy
education, inspire of taking long period to acquire.
People with developmental dyslexia have
difficulties acquiring reading and writing skills,
some show impressive talents in various fields.
Authors focus one of dyslexia ability which is
phenomenal visuo-spatial recognition abilities(von
Károlyi et al. 2003). Visuo-spatial recognition is
required to understand the three-dimensional
position of an object, which contains ample
information than 2D objects. People with
developmental dyslexia is able to recognize the
structures of characters much easier in a way of
stereoscopic 3D displays. Especially authors are
454
Yamazoe H., Kawai T., Yamagata H., Niinuma K., Ono Y. and Miyao M. (2010).
DEVELOPMENT OF STEREOSCOPIC ALPHABET LITERACY LEARNING SYSTEM FOR CHILDREN WITH DEVELOPMENTAL DYSLEXIA.
In Proceedings of the 2nd International Conference on Computer Supported Education, pages 454-457
Copyright
c
SciTePress
interested in the relationship between stereoscopic
vision and spatial perception. Stereoscopic vision
uses parallax for space perception. In the
stereoscopic researchs, the efficacy of stereocopic
information : Nakayama et al. (1989) reported that
less periods are recognized to finde at a target
among a set of distractors was shorter if the target
was in a front rather than a rear stereoscopic plane.
Shigeta et al. (1996) also showed that stereosocpic,
rather than flat, presentation is suitable for character.
The authors have developed a literacy learning
system to present hiragana characters on a
stereoscopic 3D display (Yamazoe et al. 2009). The
stereoscopic system is consisted of ordered strokes
with distinct depths. These results suggest a possibly
of the stereoscopic vision as a tool to learn hiragana
character writing for developmental dyslexia. The
aim of this study is to test the efficacy of the system
as a tool in the literacy learning of other languages.
In the present study, we have proposed the
advantage of a stereoscopic 3D display system for
supporting the alphabet character education for
children with developmental dyslexia in compared
with flat characters.
2 PROPOSED LITERACY
LEARNING SYSTEM
2.1 Stereoscopic 3D Display
A stereoscopic 3D display is effective for people to
recognize 3D patterns like a real world objects and
3D images. Most stereoscopic 3D displays are able
to recreate distinct depth objects simultaneously and
this easier for us to recognize information. In general
stereoscopic 3D display by which two images of the
same object taken at slightly different angles are
viewed together, creating an impression of depth.
Such image differences in the binocular retina are
referred to as binocular disparity. This mechanism is
known to cause visual fatigue as a result of poor
accommodation and convergence (Hatada 1988).
Due to the problems with asthenopia, stereoscopic
3D displays are not widely used for educational
purpose.
A depth fused-3D (DFD) display, rather than
commonly used stereoscopic 3D display has been
used in the present study to minimize asthenopia.
Figure 1 shows the principle of a DFD display,
which presents natural stereoscopic images without
the need for special glasses (Suyama et al. 2000).
The DFD display consists of a stack of two
transparent displays that project images from the
front and rear. Those two 2D images are the same
shape, which are almost overlapping from the
observer‟s perspective. As shown in figure 1, the
observer perceives the depths of an object depending
on the ratio of the luminance in the two displays
caused by a visual illusion. Controlling the
luminance of the two 2D images at nearest values
will produce images at intermediate depth. These
two 2D images produce a stereoscopic image that is
continuous in the depth direction. In this
stereoscopic vision mechanism, the line of sight
converges on the screen images according to the
distance from a target objects, hence there is not
discrepancy between accommodation and
convergence in human visual function.
→
Figure 1: Principle of a Depth fused 3D Display. The
luminance ratio of the front and rear rectangles changes.
2.2 Image of a Stereoscopic Character
Figure 2 shows an example of stereoscopic
character. Stereoscopic characters were rendering by
a 3D software (Autodesk 3ds Max 2009).
Stereoscopic characters are consisted of ordered pair
of strokes and depth for easily to recognize structure
of characters. DFDs Depth is set to correlate color
values with the front to rear. Gradation (0 (black) to
255 (white)) is able to make continuously depth
changing.
Figure 2: Image of a stereoscopic character.
2.3 The Contents for Alphabet Literacy
Learning
Figure 3 shows the contents of literacy learning for
alphabet. Two contents were prepared: one showed
the alphabet learning contents (Figure 3a) and the
other shows English word leaning contents (Figure
3b). Each content are show together with a
DEVELOPMENT OF STEREOSCOPIC ALPHABET LITERACY LEARNING SYSTEM FOR CHILDREN WITH
DEVELOPMENTAL DYSLEXIA
455
handwriting space. A man of learning starts to
operate the control button on the screen through the
mouse. Clicking the pronunciation button begins the
learning session. Other content is appeared by
clicking the practice button.
The literacy learning content was created by
using Flash MX 2004 (Macromedia). Content was
run on standalone Flash Player 9 used swf format
(Macromedia).
a. The alphabet learning.
Figure 3: The contents for literacy learning alphabet. The
color button changes the character color (red, yellow,
green, blue, white).
3 EXPERIMENT
3.1 Subjects
Nine subjects (four female and five males) aged
between 19 and 25 took part in this experiment. All
of the subjects had normal visual acuity, either
natural or corrected using glasses or contact lens.
The subjects agreed to participate in the study after
being given a brief description of the experiment.
Before the experiment, the subjects were asked to
write the characters they learned in the experiment,
and also the stroke order was checked. The subjects
were able to write the correct stroke.
3.2 Apparatus and Stimuli
Figure 4 shows the experimental apparatus. The
stimuli were displayed on a 9-inch DFD display
(Hitachi Displays, Ltd.) at distance of 50 cm. The
stimuli were generated from flash player and literacy
learning content formatted swf on a notebook
computer (Sony, Pentium M 1.86 GHz, Windows
XP Professional). Figure 5 shows the alphabet
stimuli. Stimuli were image of stereoscopic
characters (figure 5: B-start and B-end) and a flat
character. The screen background was black (RGB
0). Two stereoscopic characters consisted of ordered
pair of color values and depth: B-start as correlated
front to rear with a starting stroke point to end stroke
point with continuously changed. B-end as
correlated rear to front with starting stroke point to
end stroke point with continuously changed. A flat
character was rendering only white color on the
front panel of DFD. Character used “y” and “b”. The
characters consisted of “y” drawn with straight lines
and “b” drawn with a straight line and a curve.
Figure 4: The experimental apparatus.
a. B-start
b. B-end
c. Flat character
Figure 5: The parameters of stimuli.
a. Stereoscopic character: Brighten as start to darken as
end (B-start). b. Stereoscopic character: Brighten as end to
darken as start (B-end).
3.3 Procedure
Stereoscopic stimuli were shown with each alphabet
on DFD. B-start, B-end and flat were shown side by
side at random combination between the same
alphabet. Subjects watch combination of characters
total 6 times. Subject answered, “Which alphabet
character‟s writing order is understandable?” after
alphabet characters combination watched. In this
experiment “An understanding of the stroke order.”
meanings how easily to recognize to correct stroke
order.
3.4 Results
The results were shown in figure 6. The horizontal
axis was extents of understandings of the stroke
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order. Levels of understanding increasing from left
to right. Each subject‟s recognition of
understandings was analyzed by Thurstone's Paired
Comparison. B-start was significant difference from
others. B-end was significant difference from flat
character. Two characters was not significant
difference between “b” and “y”. The subjects
answered several comments about the understanding
of the stroke order used stereoscopic character.
Subjects answer was including “The stroke order is
known”, “The stereoscopic character is
understandable”, “It is legible” and “The line is clear
and understandable”.
a. Character of “b”.
b. Character of “y”.
Figure 6: Experimental results.
4 CONCLUSIONS
As shown in figure 5, the stereoscopic 3D display
was compared to the flat display for character-
comprehension tests. The data obtained suggest that
stereoscopic depth is a key factor to recognize
character efficiently. Although the exact reason for
the preferred left-start remained unclear, it might be
associated with natural order sense for depth
perception. In fact, some subjects felt a start–stroke
point as protruding at B-start, and thus readily
recognize the writing begins. In the present study,
clean advantages of stereoscopic perceptual
recognition over the flat recognition are obtained for
alphabets as well as hiragana. These data suggest
that stereoscopic 3D display is a promising tool for
the effective character learning, irrespective of
dialogue characters.
Literacy learning system incorporating many
visual elements may be effective to support the
understanding of the stroke order even for children
with developmental dyslexia. It is possible that, by
arranging alphabet characters spatially, subjects are
able to obtain information more efficiently than that
few flat presentations. The present system with
stereoscopic character has possibility to fix the
character in long-term memory. Subjects did not
complain visual fatigue while watching characters
on a DFD display. The stereoscopic characters may
be easy to recognize as DFD display. From these
results, authors propose that alphabet characters are
readily recognized on a DFD display at a
stereoscopic character of B-start. To further improve
stereoscopic literacy learning system, authors is
currently have a plan to evaluate children with
developmental dyslexia. This experiment did not
investigate a learning effective of the literacy
learning system, which is a subject for future
investigation.
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DEVELOPMENTAL DYSLEXIA
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