Star Trek’s Holodeck has just became a little closer to reality with news researchers from the University of Tokyo have developed a technique that allows 3D holograms to be “touched”. By blending a holographic display, a couple of Nintendo Wiimotes and an ultrasound phenomenon called acoustic radiation pressure, the researchers were able to create the Airborne Ultrasound Tactile Display. A system that can give the feeling of holographic raindrops hitting an outstretched hand or a virtual creature running across a palm.
The Airborne Ultrasound Tactile Display consists of three elements.
- Seeing: The Provision holographic display, which produces floating images from an LCD screen using a concave mirror. These projected images appear to float around 30 cm away from the display surface.
- Tracking: The hand-tracking technology, which makes use of the infrared camera found in the Nintendo Wiimote and a retroreflective marker placed on the tip of the user’s middle finger. Although camera-based and marker-less hand-tracking technologies are easy to come by these days, the researchers chose a Wiimote-based system for simplicities sake. Infrared LEDs illuminate the marker and two Wiimotes sense the 3D position of the finger, thereby allowing the user to handle to floating virtual image with their hands.
- Feeling: Finally the Airborne Ultrasound Tactile Display provides tactile sensation onto the user’s hand. This is accomplished using acoustic radiation pressure, which allows force to be generated at the focal point of the ultrasound emitted from the tactile display. When the tactile display radiates the ultrasound the users can feel tactile sensation on their bare hands in free space with no direct contact. The current version prototype consists of 324 ultrasound transducers with individually controlled phase delays and amplitudes to allow one focal point to be generated and moved three-dimensionally.
The prototype in the video below shows a user feeling a raindrop hit their palm and feeling a small virtual creature running across their palm. Since the system doesn’t require the use of a physical object within the workspace, the appearance of the holographic images isn’t diluted.
The researchers from the University of Tokyo believe touchable holographs will find applications in video games, 3D Computer Aided Designs, amongst other uses.