The future of touch
Researchers uncover physical limitation in haptic holography

Date:
March 1, 2023
Source:
University of California - Santa Barbara
Summary:
Haptic holography promises to bring virtual reality to life, but
a new study reveals a surprising physical obstacle that will need
to be overcome.


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FULL STORY ========================================================================== Haptic holography promises to bring virtual reality to life, but a
new study reveals a surprising physical obstacle that will need to
be overcome.


==========================================================================
A research team at UC Santa Barbara has discovered a new phenomenon
that underlies emerging holographic haptic displays, and could lead to
the creation of more compelling virtual reality experiences. The team's findings are published in the journal Science Advances.

Holographic haptic displays use phased arrays of ultrasound emitters
to focus ultrasound in the air, allowing users to touch, feel and
manipulate three- dimensional virtual objects in mid-air using their
bare hands, without the need for a physical device or interface. While
these displays hold great promise for use in various application areas, including augmented reality, virtual reality and telepresence, the tactile sensations they currently provide are diffuse and faint, feeling like a "breeze" or "puff of air." "Our new research explains why such holograms
feel much more diffuse or indistinct than would be expected," said Yon
Visell, an associate professor of electrical and computer engineering,
whose research focus is on interactive technologies with an emphasis on haptics, robotics and electronics.

The study led by Visell and Gregory Reardon, a doctoral student
researcher, used high resolution optical imaging, simulations and
perception experiments to study ultrasound-excited waves that are excited
in the skin during haptic holography. They discovered that holographic
displays excite widespread vibration patterns -- shear shock waves --
in the skin.

In haptic holography, Visell explained, shock waves are created when
ultrasound waves are focused and scanned in mid-air, causing vibrations
in the skin. These vibrations can interfere with each other in a way
that amplifies their strength at some locations, a phenomenon known
as constructive interference. The formation of shock waves creates
a trailing wake pattern that extends beyond the intended focal point,
reducing the spatial precision and clarity of the tactile sensations. As
an analogy, according to the researchers, if the focused sound beam is a fast-moving boat on the water, the shock wave pattern is a wake trailing
the boat. Current holographic haptic displays excite shock wave patterns
that are so spread out in the skin that the sensations feel very diffuse.

"Our study reveals how holographic haptic displays, which are a promising
new technology for virtual reality and telepresence, require new knowledge
in acoustics innovations in design," Visell said. "By understanding the underlying physics of ultrasound-generated shear shock waves in the skin,
we hope to improve the design of haptic holographic displays and make
them more realistic and immersive for users. Such haptic displays could
enable us to augment our physical surroundings with a limitless variety
of virtual objects, interactive animated characters, or graspable tools
that can be not only seen, but also touched and felt with the hands."
The team's discovery of the previously unknown shock wave phenomena that underlie haptic holography provides an important step forward in creating haptic holographic displays that may enable users to more realistically
and immersively interact in the future metaverse.

* RELATED_TOPICS
o Mind_&_Brain
# Educational_Psychology # Consumer_Behavior # Perception
o Matter_&_Energy
# Virtual_Environment # Engineering # Quantum_Physics
o Computers_&_Math
# Virtual_Reality # Computer_Graphics # Video_Games
* RELATED_TERMS
o Virtual_reality o Phobia o Acoustics o Spectroscopy o
Physical_cosmology o Radiography o List_of_cognitive_biases
o Developmental_disability

========================================================================== Story Source: Materials provided by
University_of_California_-_Santa_Barbara. Original written by Sonia
Fernandez. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gregory Reardon, Bharat Dandu, Yitian Shao, Yon Visell. Shear
shock waves
mediate haptic holography via focused ultrasound. Science Advances,
2023; 9 (9) DOI: 10.1126/sciadv.adf2037 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/03/230301162709.htm

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