BACKGROUND: VirtuSphere is the first all-directional virtual reality device. It is an 8.5-foot hollow ball. The user steps into the ball wearing a wireless, head-mounted virtual display, and can walk, jump, roll, crawl or run in any direction over virtually unlimited distances -- without encountering real-world physical obstacles. Possible applications include rehabilitation, exercise, gaming and other forms of entertainment, museum exhibits, virtual travel, fire prevention training, and even science education, since the VirtuSphere would enable a simulation of walking on the Moon.
HOW IT WORKS: The head-mounted display provides the user with the virtual environment. Sensors under the sphere provide the speed and direction of the user's movement to the computer running the simulation. So as the user moves, the VirtuSphere ball rolls, sending coordinates to the computer. The computer then evaluates this information and relays it back to the user's display, changing the view. Users can also interact with objects in virtual space using a manipulator called a haptic interface.
THE DOPPLER EFFECT: Doppler radar, an ultrasound device, helps detect precisely how much the sphere is moving so the user can be tracked step by step. Doppler radar uses a well-known effect called the Doppler shift. A moving object that's emitting light can seem to change color depending on whether it's moving toward or away from you. Light emitted by a moving object seems to increase in frequency, and looks more blue, if it is moving toward the observer; if the object is moving away from us, it will be shifted toward the red end of the spectrum. The same is true of sound: sound waves reflected by something moving away from the source change to a lower frequency, while those from an object moving toward a source change to a higher frequency. That's why a train whistle will sound higher as it approaches a platform and then become lower in pitch after it passes you and moves away. Doppler radar sends out radio waves that bounce off objects in the air, such as raindrops or snow crystals, and then measures how much the frequency changes in returning radio waves to better determine wind direction and speed.
WHAT IS VIRTUAL REALITY: The term "virtual reality" is often used to describe interactive software programs in which the user responds to visual and hearing cues as he or she navigates a 3D environment on a graphics monitor. But originally, it referred to total virtual environments, in which the user would be immersed in an artificial, three-dimensional computer-generated world, involving not just sight and sound, but touch as well. Devices that simulate the touch experience are called haptic devices. Touch is vital to direct and guide human movement, and the use of haptics in virtual environments simulates how objects and actions feel to the user. The user has a variety of input devices to navigate that world and interact with virtual objects, all of which must be linked together with the rest of the system to produce a fully immersive experience.
The Human Factors and Ergonomics Society and the Institute of Electrical and Electronics Engineers, Inc., contributed to the information contained in the TV portion of this report.