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 it´s 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@hotmail.com ou mcgac@coc.ufrj.br Results and Discussion There are hundreds of throwing techniques and combinations in Judo [13; 14;15] 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 book–store 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. • References: • AZUMA, R Overview of augmented reality. Presence: Proceedings of the conference on SIGGRAPH 2004, course notes, GRAPH '04, http://delivery.acm.org/10.1145/1110000/1103926/cs25.pdf?key1=1103926&key2=0745042411&coll=GUIDE&dl=GUIDE&CFID=71391857&CFTOKEN=78299468. • MILGRAM, p & KISHINO, F A taxonomy of mixed reality visual diplays. IEICE Transactions on Information Systems, v. E77-D, n. 12, December, 1994. • AZUMA, R et al. Recent advances in augmented reality. 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