Game Development Reference
A new tactile interface called VITAL (acronym of VIbroTActiLe) was developed
at the CEA-List and presented in (Benali-Khoudja, 2004). VITAL is made up of an
active surface of 8
8 electromagnetic actuators. The manufacturing of the actuators
is based on a new multi-layer concept that allows high density, integrated addressing
and reduced production costs (Benali-Khoudja, 2003). An electromagnetic optimi-
sation has been carried out in order to satisfy the specifications in terms of force
(Benali-Khoudja, 2004). A future version of VITAL will help to associate the thermal
rendering modality (Benali-Khoudja, 2003; Benali-Khoudja, 2004) to the mechanical
skin deformation modality (pressure or vibration).
10.4.2.3 Tactile interfaces for sensory substitution
The objective here is to translate visual, auditory or other information into tactile
information. Several interfaces have been made for this purpose, the most common
being TVSS (Tactile Vision Substitution System). In this section, we shall present some
examples of these interfaces that are often used to assist handicapped persons.
The fusion of tactile and visual rendering, in order to increase performance during
perception, aroused special interest at the Kirchhoff Institute for Physics, University of
Heidelberg in Germany (Maucher, 2000). In order to realise this, an image acquisition
system has been designed. This system was coupled to a tactile interface VTD (Virtual
Tactile Display). The VTD interface is 230
300mm 2 with a resolution of 2880 taxels
and a working frequency of 50Hz. The actuation technology is piezoelectric.
The tongue, states Paul Bach-y-Rita, inventor of the TDU (Tongue Display Unit)
interface, from the University of Wisconsin-Madison, is a potential portal of informa-
tion to the brain (Sampaio et al., 2001). Electrotactile stimuli are delivered above the
tongue when it comes in contact with a flexible configuration of electrodes placed in
the mouth. A tongue display unit, connected to the electrode matrix by a cable passing
outside the mouth, stimulates various electrodes on this matrix following a spatial
signal coded using an input source.
Optacon (OPtical-TActile CONversion), from TeleSensory Corp Mountain View
CA, is made up of a hand-held camera with an arrangement of photocells (6 columns -
24 lines), and a corresponding tactile actuator, also composed of 6-by-24 pins measur-
2.7 cm (Tan & Pentland, 1997). Optacon II, also a product of TeleSensory
Corporation, provides the visually impaired with more access to the display systems
by windowing (Xwindows type).
The German company Abtimdeveloped an interface consisting of two independent
parts communicating through a wireless transmission system. The first part, which can
be very easily held in the hand, helps to scan images. The second part presents a tactile
screen of 256 sticks on a 4
4cm 2 grid that transforms images into black and white,
then simplifies them and then converts them into a tactile representation. The interface
weighs approx. (800 g) and the overall dimensions are (14
3cm 3 ).
10.4.2.4 Tactile interfaces for the generation of a 3D surface
In order to provide more transparency of the interface vis-à-vis the operator, researchers
have suggested concepts and projects that do not restrain any part of the body (for
example, the hand may not be linked to or placed on the interface) to remain connected