September 2, 2008

Researchers Use Ultrasound To Give Feel To Video Games

Japanese researchers are now able to use ultrasonic waves to produce "virtual" objects in mid-air.

Integrating computing and the sense of touch, known as the field of haptics, has been around for some time but has required gloves or mechanical devices to impart a sense of feeling.

Now researchers have developed a system that uses focused ultrasound to do the job and its inventors may soon commercialize the approach.

Multimedia expansion on the web has left our eyes and ears flooded with sensory information, but the sense of touch has been largely left behind.

The popularity of vibrating gaming handsets has proven that it is a rich but untapped way to increase interaction.

But now Takayuki Iwamoto and colleagues from the University of Tokyo demonstrated a simple haptic device that employs a number of ultrasonic transducers, which emit ultrasound.

Sound is a pressure wave, meaning that as the inaudible sound waves from each of the transducers interfere, they can create a focal point that is perceived as a solid object.

The prototype system includes a camera that tracks the position of a user's hand and shifts the output from the transducers to move the focus around with the hand. The result is a feeling of tracing the edge or surface of the virtual object.

So far, the system provides a small force only in the vertical dimension, but the team is improving the geometry of the array and the amount of power it can produce so that future devices will provide a stiffer feel and more contoured objects.

Professor Iwamoto says that the team "received several proposals from industrial companies" when the prototype was demonstrated at a conference in California last month.

According to haptics researcher Stephen Brewster of the University of Glasgow, this system is "the first of its kind".

Brewster says you can feel it with both hands, rather than having just a single point of contact, and multiple people can use it at the same time.

"The kinds of things we use are connected through mechanical arms or you're wearing some kind of exoskeleton. It's great to have something that you can just walk up and use and not need any other kind of hardware you have to hold or wear."

Researchers are working to adjust how the transducers are driven in order to produce realistic textures as well as shapes.

However, the approach is limited in how much force it can produce, which in turn limits how hard or stiff the virtual objects can be. Beyond a certain amount of force, the device could scatter enough ultrasound to risk ear damage.


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