INVISIBLE ~The Shadow Chaser~

An interactive game that helps players sense unseen existences through indirect information such as their shadows, sounds, and weights. In this game, "invisible" goblins sneak around, but you can only see their shadows. Your mission is to chase their shadows and capture them with a special vacuum.

Enhanced Life
This project presents an object's existence in the real world using multimodal perceptions, a concept that may be useful for supporting barrier-free services for handicapped people in public and entertainment spaces.

Goals
The goal of this project is to help users feel the existence of specific objects through indirect information and to show that the approach can be effectively implemented as a simple virtual reality system.

Innovations
The interactive system allows users to feel the presence of 3D virtual objects without stereoscopic visual information. It includes:

1. Capturing 3D information (position and orientation) from the projector. For natural projection of the shadow shapes, the 3D position and orientation of the projector are obtained in real time with a simple method: The observed pattern of the LEDs is corrected by the orientation of the gyro, so the size of the LED pattern shows the distance from the camera. This combination of the 3DOF tracker and the simple LEDs arrangement enables high-speed tracking and positioning of the projector device.

2. A system to present indirect information (shadows, sounds). To make players feel the goblin's existence, the system provides indirect information such as the shadows and sounds of goblins instead of direct images. 3. A capture device. The responses of the goblins are very important. Players feel a sense of capture through vibration weight change. A number of small vibrating motors are fixed in the hose of the device. When players capture the goblin, these motors vibrate sequentially from the nozzle toward the handle. Then a large vibrating motor in the backpack presents a sense that the captured goblin is struggling. At the same time, water is moved from a tank on the ground to another in the backpack, so players feel the weight of the captured goblins.

Vision
When users experience INVISIBLE, they feel that fantasy objects actually exist, as children imagine that their fantasies are real as they listen to fairy tales. The projector displays a 3D object's existence and behavior. Simple location techniques monitor users' intentions and react to them.

The system demonstrates a new technique for integrating the real world and the virtual world. The next generation of this work will create a world in which many people clearly sense the existence of virtual objects and freely interact with and control them.

Contact
Yoshinobu Nakano
Nara Institute of Science and Technology
shadow (at) is.naist.jp

Contributors
Kunihiro Chihara
Masako Fukushima
Kenji Kawashima
Hitomi Komura
Haruka Ouwa
Masayuki Sagano
Taku Shirazawa
Soushi Tujimura
Daisuke Watanabe
Masayuki Yamazaki
Yasuhiro Yoshimura
Nara Institute of Science and Technology