Technology that lets you 'feel' textures on touchscreen

Smartphone users can now 'feel'
images and objects seen on their
touchscreen!
In a game-changing invention,
engineers at Disney Research,
Pittsburgh, have developed a new
technique that allows you to feel the
texture of objects seen on a flat
touchscreen.
The novel algorithm enables a
person sliding a finger across a
topographic map displayed on a
touchscreen to feel the bumps and
curves of hills and valleys, despite
the screen's smooth surface.
The technique is based on the fact
that when a person slides a finger
over a real physical bump, he
perceives the bump largely because
lateral friction forces stretch and
compress skin on the sliding finger.
By altering the friction encountered
as a person's fingertip glides across
a surface, the Disney algorithm can
create a perception of a 3D bump on
a touch surface.
The method can be used to simulate
the feel of a wide variety of objects
and textures.
"Our brain perceives the 3D bump
on a surface mostly from information
that it receives via skin stretching,"
said Ivan Poupyrev, who directs
Disney Research, Pittsburgh's
Interaction Group.
"Therefore, if we can artificially
stretch skin on a finger as it slides
on the touchscreen, the brain will
be fooled into thinking an actual
physical bump is on a touchscreen
even though the touch surface is
completely smooth," Poupyrev said in
a statement.
In experiments, researchers used
electrovibration to modulate the
friction between the sliding finger
and the touch surface with
electrostatic forces.
Researchers created and validated a
psychophysical model that closely
simulates friction forces perceived by
the human finger when it slides over
a real bump.
The model was then incorporated
into an algorithm that dynamically
modulates the frictional forces on a
sliding finger so that they match the
tactile properties of the visual
content displayed on the
touchscreen along the finger's path.
A broad variety of visual artifacts
thus can be dynamically enhanced
with tactile feedback that adjusts as
the visual display.
"The traditional approach to tactile
feedback is to have a library of
canned effects that are played back
whenever a particular interaction
occurs," said Ali Israr, a Disney
Research, Pittsburgh research
engineer who was the lead on the
project.
"This makes it difficult to create a
tactile feedback for dynamic visual
content, where the sizes and
orientation of features constantly
change. With our algorithm we do
not have one or two effects, but a
set of controls that make it possible
to tune tactile effects to a specific
visual artifact on the fly," Israr said.
The new research will be presented
at the ACM Symposium on User
Interface Software and Technology in
St Andrews, Scotland.