Disney researchers have found a way for
people to "feel" the texture of objects seen
on a flat touchscreen.
The technique involves sending tiny vibrations
through the display that let people "feel" the
shallow bumps, ridges and edges of an object.

The vibrations fooled fingers into believing they
were touching a textured surface, said the
Disney researchers.

The vibration-generating algorithm should be
easy to add to existing touchscreen systems,
they added.

Developed by Dr Ali Israr and colleagues at
Disney's research lab in Pittsburgh, the
vibrational technique re-creates what happens
when a finger tip passes over a real bump.
"Our brain perceives the 3D bump on a surface
mostly from information that it receives via skin
stretching," said Ivan Poupyrev, head of the
interaction research group in Pittsburgh.

To fool the brain into thinking it is touching a
real feature, the vibrations imparted via the
screen artificially stretch the skin on a fingertip
so a bump is felt even though the touchscreen
surface is smooth.

The researchers have developed an underlying
algorithm that can be used to generate textures
found on a wide variety of objects.

A video depicting the system in action shows
people feeling apples, jellyfish, pineapples, a
fossilised trilobite as well as the hills and valleys
on a map.

The more pronounced the feature, the greater
the vibration is needed to mimic its feel.

The vibration system should be more flexible
than existing systems used to give tactile
feedback on touchscreens, which typically used
a library of canned effects, said Dr Israr.
"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 artefact
on the fly," he added.