A Tetris Game for the Visual Impaired Utilizing Sound

A Tetris Game for the Visual Impaired Utilizing Sound Jongmyung Choi, Daehee Park, Rang Lee, Seonhwa Kim Computer Engineering, Mokpo National University, Jeonnam, South Korea {jmchoi, daehee.park, rang.lee, seonwha.kim}@mokpo.ac.kr

Abstract. Games bring happiness, fun, and achievement, so that games have been enjoyed and applied to education and other serious activities. However, there have not been enough games for the visual impaired. In this paper, we introduce a Tetris game for the visual impaired. To enable them to play, we 1) simplified game rules, 2) supported only one kind of piece, and 3) utilized sound for noticing holes to fit in. We introduce three contributions to games for the visual impaired: the first Tetris game, the possibility of sound based complex games and the enhancement of quality of life by the game. Keywords: Game, Tetris, Visual Impaired, Sound

1

Introduction

Games enable people to have fun, overcome difficulties, and feel happiness and achievement. Therefore games have been enjoyed by people and have been applied to serious activities such as education and changing human behavior. We can say that games have enhanced our quality of life in various aspects. Nowadays computer games are very common and popular and most of people enjoy computer games. However the visual impaired have difficulties in playing computer games unfortunately. The visual impaired are classified into two groups: blind and low vision. In the world, 285 million people are visually impaired; 39 million of them are blind and the others have low vision [2]. In Korea, about 252 thousand people have registered to the government as the visual impaired in 2012 [3]. There have been various researches on helping the visual impaired such as street guide system and communication system with friends. However, people have not paid much attention to computer games for the visual impaired. It is because most of computer games are based on human vision and there have not been enough games that use other sensors. In this paper, we propose a simplified Tetris game for the visual impaired. For the visual impaired, we designed the Tetris game with these features: sound-based game, big and high contrast pictures, simple game scenario, and multi levels for achievement. In order to understand visual impairment and to gather the requirements of games for the visual impaired, we conducted interview with two persons: one was blind, and the other had low vision. Based on the gathered requirements, we considered three games scenarios, selected one of them, and implemented a prototype game. We con-

ducted interview with them to test our idea and evaluate the game. After the meeting, we modified the game to meet their evaluation results. Our work introduces three contributions to games for the visual impaired and other disabled. First, we introduce the first Tetris game for the visual impaired. Second, we show the possibilities and plausibility of games does not utilize human vision. Third, we get to know some new knowledge from Tetris game experiment. This paper consists of four sections. In section 2, we will summarize the related works and compare them to our work. After then, we describe the requirements, design issues, and evaluation results in section 3. Finally, we will reveal our conclusions in section 4.

2

Related Work

The existing researches that are related to our work are rather rare. Some researches on ICT systems for the visual impaired have been done. However those researches are to provide usefulness to the visual impaired, so that those researches are different from our work. Patomäki's work [6] was about testing procedure for multimodal interface (especially, haptic) environments which were for game and education. This work proposed a good testing procedure of stylus style haptic device and haptic empowered applications for visually impaired children. Sablé’s work [7] introduced a multimodal game platform specially designed for the visual impaired. The game platform help experts (but not programmers) to create games for the visual impaired, and it adopts various input and output devices for them such as screen, keyboard, Braille terminal, 3D sound and a tactile board. Buaud's research [1] proposed methodology for developing adapted games for the visual impaired. In the work, they proposed half-separated process: for technology and for user need. Their work could be useful for systematic approach to game development.

3

Requirements Analysis and System Design

In this section, we describe how to gather requirements and design game scenario, user interface, and system classes. 3.1

Gathering Requirements

We conducted interview with two visually impaired persons to understand their situation and gather basic requirements for the games. One is female blind in her 20’s, the other is very low-vision male in his 40’s. Our questions were mainly about to understand their situation: “Tell us your situation”, “Do you like to play computer games?”, “What kind of computer games do you want?”, and “Tell us computer games for the visual impaired that you know”. The interview lasted about 30 minutes for each interviewee. Fig. 1 shows the scene of the interview.

Fig. 1. Requirement Gathering Interview

From the interview, we gathered some requirements of games for the visual impaired. • R1. Short cut keys: They have difficulties in using mouse, so that they prefer to using keyboard and short cut keys. • R2. Achievement: The game should be designed for the players to feel achievement. Therefore, it should have the concept of levels and the levels should be able to be overcome by practice. • R3. Using both hands: Games that can be played with one hand can be boarded, so that both hands playing games are much preferred. • R4. Difficulties: The games should be easy enough for novice players to enjoy the game. Most of the visual impaired do not have experience of various computer games, so that they should be considered as novice players. • R5. Pause: Game players should be able to pause the game temporarily for other activities. • R6. Chatting: In the middle of playing game, they want to chat with their friends. • R7. High Display Resolution: Most of the visual impaired are people with low vision. It means that they have difficulties in seeing but they can see. Therefore, the system should support high resolution display and big screen. 3.2

System Design

3.2.1 Game Scenario Design In the beginning of design, we had to determine game scenario. We choose Tetris game for the project because it has been very popular for decades, and there have not been any Tetris game for the visual impaired. Furthermore, it is rather easy to implement and does not require much resources or extra devices except desktop computer. After determining game category, we have to consider Tetris game scenarios and user interface devices. The traditional Tetris has stereotyped game rules but they cannot applied to our game because our players have difficulties in seeing the pieces and

some of them even cannot see at all. Therefore we determined to use sound, and we redesigned Tetris game and simplified it. Fig. 2 shows the basic game scenario. In the bottom, there is a line of pieces and there is a hole in the line. The line goes up at a specific time interval, and the game is over if the line goes to the top. The location of a hone in a line is random. When the game starts, the bottom line appears, and a piece goes down from the top at a specific time interval. And the player can move the piece left and right. When the piece moves, the game plays heptatonic scale sound according to its location in horizontal. In addition, if the location of the piece matches the location of the hole, it plays different sound, not heptatonic scale sound. Therefore, the player can know where he/she can put down the piece in the Tetris game.

Fig. 2. Tetris Game Scenario

3.2.2 System Design We designed Tetris game twice: after analyzing initial requirements and after evaluating initial prototype. Fig. 3 shows the final version of system classes and their relationship. At initial design, we referred and modified the existing Tetris game introduced in a book [4].

Fig. 3. Class Diagram of Tetris

In the class diagram, TetrisCanvas class draws every graphic element including the stacked pieces, and it also handles user events such as key events. TetrisData class manages information of stacked pieces. Piece class represents a piece of Tetris.

4

Implementation and Test

4.1

System Implementation

The Tetris has been implemented on Java platform by modifying a game introduced in a book [4]. We have utilized FreeTTS [5] for text-to-speech module to announce the current score and other information to the visually impaired players. Fig. 4 shows the game screen. In the center, there is the game play screen which consists of 10 x 8 grid panel. On the left, there are three information panels that show left time, number of deleted line, and the current score. The picture and text are designed to be big, large, and high contrast colored for the people with low vision. The current score is announced in audio via TTS each time when the score is changed.

Fig. 4. Tetris Game Screen

For achievement, we designed the concept of levels, and at first the player is given 60 seconds. If the time is ended, the game stops. However, if the player deletes more lines than a specific number, which is different according to levels, the level goes up and time is extended. For input devices, we adopt keyboard and three button-type devices. Those button devices are connected to the computer via AViX device gateway, and they match to the three keys in the keyboard that manipulate the current Tetris piece. Fig. 5 shows the device gateway and three button devices.

Fig. 5. Button Input Devices

4.2

System Test and Future Work

We tested the Tetris with normal people with eye patch and the male with visual impairment who we conducted interview for requirement gathering. Fig. 6 shows the scene of evaluation interview after game testing. The game was enjoyable by the visual impaired. He preferred keyboard to button devices because keyboard is more familiar to him.

Fig. 6. Evaluation Interview

The game still has much room to be improved. First, we have to pay attention to the balance between achievement, difficulty, and fun in playing. Therefore, we need to redesign more sophisticate level-up mechanism. Second, we need to create more enjoyable game scenario. The current game scenario is rather simple that it may be boring when people play it many times. Third, we need to create or design more vision impairment friendly input and output devices. Especially, the current display output device is not friendly to the visual impaired. Therefore, we need to invent or create output devices for the visual impaired.

5

Conclusions

Games are very important element in our life for fun, happiness, and achievement. Nowadays, computer games have been very common, however the visual impaired have not enjoyed computer games enough because we have not have enough games for them. In this paper, we introduced a Tetris game which was specially designed for the visual impaired. We modified and simplified the existing Tetris game, and utilized sound to let them identify where the hole was and where the current piece was. After the evaluation of the game, we found that sound-oriented games were possible for the visual impaired, and they enjoyed the game. However, we also found that visual display should be provided and it should be sophisticated designed considering graphic size, contrast, and colors. Third, special input devices should be carefully designed because they preferred familiar devices that they used every day. We also found that even though Tetris is a simple game, it can be redesigned for the visual impaired or other disabled people.

Acknowledgments. We appreciate Jeonnam Branch of “The Research Institute of the Differently Abled Person’s Right in Korea” (especially, Mr. Youngson Son) for their helps in the interview, test and evaluation of the game. This research started from “Object Oriented Programming” class term project in Mokpo National University, and it has been financially supported by the MSIP(Ministry of Science, ICT & Future Planning), Korea, under the "Seoul Accord Vitalization" support program(NIPA H1807-13-1013) supervised by the NIPA(National IT Industry Promotion Agency).

6

References

1. Aurélie Buaud, Harry Svensson, Dominique Archambault,and Dominique Burger : Multimedia Games for Visually Impaired Children, Computers Helping People with Special Needs, LNCS vol. 2398, pp. 173--180, Springer (2002) 2. WTO, Visual impairment and blindness, Fact Sheet N°282, June, 2012, available at http://www.who.int/mediacentre/factsheets/fs282/en/ 3. Statistics Korea, Fact Sheet of the Disabled, July, 2013, available at http://index.go.kr/egams/stts/jsp/potal/stts/PO_STTS_IdxMain.jsp?idx_cd=2768 4. Jongmyung Choi, Youngho Lee, Su Lyul Oh : Java Object-oriented Programming: Solving Problems, Hongreung Science Pub. (2011) 5. FreeTTS, available at http://freetts.sourceforge.net/ 6. Saija Patomäki, Roope Raisamo, Jouni Salo, Virpi Pasto, and Arto Hippula : Experiences on Haptic Interfaces for Visually Impaired Young Children, Proc. of the 6th international conference on Multimodal interfaces, pp.281--288, ACM (2004) 7. Sébastien Sablé and Dominique Archambault : Blindstation : a Game Platform Adapted to Visually Impaired Children, Assistive Technology– Shaping the future, Proc. of the AAATE’03 Conf., pp.232--236, IOS Press (2003)