Abstract

1
AUGMENTED REALITY APPLIED TO USHIRO-UKEMI
VISUALIZATION

• Abstract
• The last fifty years has promoted intense
  development of Sports Sciences. As time goes by,
  new kinds and sources of knowledges have beeen
  applied to sports movement comprehension. So its
  time to present a new link of options dealing
  with the cientific visualization, high
  performance computing, virtual reality and
  Sports. This study aims to create an Augmented
  Reality (AR) system to promote the visualization
  of different media files presenting the
  Ushiro-Ukemi movement. For such, the following
  steps were done
• animated files were created
• markers were printed in different materials
• an AR system were created with these media files
  aplied.
• 3D Studio Max, Photo Impact, Macromedia Director,
  DART and Microsoft Word softwares and a computer
  with a Pentium 4 HT, computer with a G-Force 4
  graphic board, web cam, a monitor and a data show
  pojector were used the development of this study.
  The system provided the visualization of
  Ushiro-ukemi in motion. This system may be
  applied to any written materials like books
  allowing sports movement visualization flowing
  along with the time instead of static images
  generally seen. It may be applied also during
  public presentations promoting interaction
  between a single reader at home or during a
  public audition with these materials.
• Keywords Augmented Reality, Judo, Physical
  Education, and Virtual Reality.

Mauro Cesar Gurgel de Alencar Carvalho (1, 2,
5) Estélio Henrique Martin Dantas (3) Gerson
Gomes Cunha (5) Luis Landau (5) Homero da Silva
Nahum Junior (4) (1) JUDÔjo Grupo de Estudo e
pesquisas de Judô (2) Colégio Pedro II (RJ) (3)
LABIMH Universidade Castelo Branco (RJ) (4)
Universidade Estácio de Sá (5) LAMCE PEC
COPPE Universidade Federal do Rio de
Janeiro mauro_gurgel_at_hotmail.com ou
mcgac_at_coc.ufrj.br
Results and Discussion There are hundreds of
throwing techniques and combinations in Judo 13
1415 and they are applied many times during a
class or training session.
Introduction Mankind has represented human
activities since hunting figures were drawn in
cave walls. Nowadays books also show pictures of
sport movements, but they are static pictures and
cannot present the movement flowing along the
time. The application of an Augmented Reality
(AR) system may provide a better perception and
interaction 1 about the sports skills that are
not reached by regular books.
Figure 3 O-soto-gari 16 17 18
The judoka falls over his scapulaes when a Judo
throw is performed, like an O-soto-gari, for
example. Obviously he must execute a breakfall
(Ukemi) properly. The Ukemi is a fundamental
ability to be acquainted during Judo practice.
To teach and learn the Ukemi properly are a
teachers and students basic obligations when
practicing Judo, respectively 11.
Figure 1 Representation of an RV Continuum 1.
The relation between real and virtual environment
was firstly explained by reality-virtuality
continuum proposed by Milgram Kishino 2 and
adapted for a better understanding to these
concepts 1. This paper accepts the following
definition for Augmented Reality (AR) 3 an
AR system supplements the real world with virtual
(computer-generated) objects that appear to
coexist in the same real world . While many
researchers broaden the definition of AR beyond
this vision, we define an AR system to have the
following properties combines real and virtual
objects in a real environment runs
interactively, and in real time and registers
(aligns) real and virtual objects with each
other. In AR systems, sound may be synthesized
by the computer or captured from real environment
and put together. Even voice commands may be
applied to promote behavior changes in the
virtual objects. The interaction between virtual
and real environments with the user may be given
by mouse or even voice commands 4, gloves with
force feedback allow interactions. Hardwares such
as head mounted display, stereoscopic glasses and
monitors may be used for such 5 6 7 8.


Figure 4 pedagogic progression from laying to
sitting, to squating, and to standing position
for Ushiro-ukemi learning.

• The first Ukemi to be learned is the
  Ushiro-ukemi. Performing the Ushiro-ukemi
  pedagogic progression, the judoka learns how to
  fall smooth and safely through steps that go from
  the easier to the most difficult skill.
  Traditionally it varies from laying, sitting
  (za-i), squat (tyu-goshi) and standing (ritsu-i)
  positions, as presented in figure 4.
• Operational procedures
• To convert regular Ushiro-ukemi animated files to
  flash and to shockwave3D file.
• Create a plan as a Sprite to serve as screen to
  2D animated files.
• Set the new flash files as texture in the plan.
• To develop the Judo printed material with a
  fiducial marker inside and a cube with fiducial
  markers on its sides.
• To insert the animated file in Cast of Macromedia
  Director, applying behaviors and testing its
  performance.
• To create the Macromedia Director file and
  executable program
• The standing Ushiro-ukemi movement is shown when
  the webcam focuses the marker at a page of the
  instructional material. As focalized by the
  webcam, the marker was identified by the
  executable program.

Figure 2 visualization of virtual objects
popping out from an instructional material in
real environment
The evolution of hardware and software computing
resources has allowed the development on
visualization techniques 9. Markers printed
inside text books may be very useful for
educational purposes 10 11, even for children
with hearing impairment 12. Objective This
study aims to create an Augmented Reality (AR)
system to promote the visualization of different
media files presenting the Ushiro-Ukemi movement,
while focusing a printed marker at Judo Manual,
showing the ushiro-ukemi movement flowing along
the time. Material and methods A home computer
with a Pentium 4 HT processor, 2,8 MHz, 512 Mb
DDRAM, G-Force-4 5200 graphic board, an Olympus
F-120 digital camera, and a webcam A4Tech
hardware were used with these softwares 3D
Studio Max, Photo Impact, Macromedia Director,
DART and to develop the specific files and
executable program, and Microsoft Word for the
Judo material with a marker printed inside.
Figure 7 Animated 3D file applied on a Judo
reading material and a cube with an AR system
combined.
Figure 6 Animated 2D file applied on a Judo
reading material and a cube with an AR system
combined.
Figure 5 Fiducial Marker example.
Immediately the monitor or the see-through
glasses show a screen popping out of the paper
and presenting the Ushiro-ukemi movement. The
integration of motion picture of a sport and the
application of augmented reality techniques may
provide a better perception, interaction and
understanding about the Ushiro-ukemi rhythm
because it provides the movement visualization
flowing with the time that are not reached by
regular books. So the reader may perceive the
amount of time spent in every phase of the
Ushiro-ukemi.
Conclusions Physical Education and Sports books
should provide movement pattern visualization,
but it was not possible in this kind of media yet
because only static pictures could be seen.
Another media, the CD-ROM provides movement
visualization however reading in this type of
media also may cause eye irritation and some
other health problems due to monitor radiation
and intermittent light exposure 11. This study
represented a new approach for specialized books
on Sports, specifically for Judo. The combination
of AR system with a book increases its capacity
to present any specific sport skill in a motion
picture. In a near future, AR system associated
to books may be found in the bookstore next
door. It may represent a new generation of books
in the market, where any end-user who owns a
simple webcam and a home computer will be able to
visualize any sport movement while reading a book.

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