full Paper - Nguyen Dang Binh

Figure 5: A 3D city-map in the GRAB system.
• General features inside of a haptic session: zoom, panning,
get inventory of a street and/or a block, get information
about the User position,..
• Multiple User interfaces: keys, audio, buttons and haptic
effects (tapping and pausing).
•
4. Validating the GRAB system and applications
The GRAB system was tested with a total of 52 participants
across the three user organisations of the project (RNIB,
NCBI and ONCE). A deep analysis of the features of the
GRAB system when applied to visually impaired people was
conducted in the project. This analysis enabled to identify
a few key features and bene£ts that the GRAB system can
bring to blind and visually impaired people with respect to
other current haptic systems. The main advantage is related
to the use of two contact points. Observation and user responses
indicated that a second £nger - on a separate hand -
can be vital as a ’anchor’ or reference point that allows the
user to orientate themselves in space, more readily understand
objects’ relationships (distribution and distances) and
makes re-£nding objects easier. Other issues that the users
most appreciated are:
• Larger workspace than other haptic devices
• Smooth re£ned movement
• Robustness of the device
• Position accuracy
• High peak forces
• Fidelity, especially in terms of judging sizes and comparative
distances
• Interaction and exploration of objects, including features
like: weight, stiffness, stickiness, curvatures, attraction
forces, following a trajectory, utilities to £nd, recognise
and explore small objects, ³E
• Audio input and output
• Interaction with a changing environment (buttons, moving
objects, organising objects, detecting collisions ³E)
c○ The Eurographics Association 2005.
Massimo Bergamasco / Future trends and Applications, Medicine
56
On average, twelve people tested each one of the above
applications. Before starting the validation phase, the application
was introduced to each partner through a tutorial
speci£cally designed to familiarise the user with the main
features of the application. The results of the validation of
these applications, in particular based on users’ comments
and evaluators’ observations, con£rm the validity and potential
of the GRAB system for these kinds of applications,
although some features require some adjustments to create
future usable tools.
5. Conclusions
In this papers a new Haptic & Audio System (GRAB) interacting
within ¤exible Virtual Environment has been presented.
The system is provided with a set of applications that
allow visual impaired to access to the 3D graphic computer
world through the sense of touch and with audio help. The
GRAB system features context aware audio synthesis as well
as speech recognition. Haptic interaction can feature object
exploration, simple manipulation and control (buttons and
haptic recognition). Both modes can be made interacting enhancing
in such a way the interaction design. The system has
been proved on the £eld with a wide set of users and in cooperation
with different European institutions for blind users.
In order to demostrate the validity of the approach, three applications
for visual impaired people were implemented: a
searching and adventure game, a city map explorer and a
chart explorer. Nonetheless, the GRAB system has been conceived
openly in order to easily provide a support in the design
and development of audio-haptic applications for other
£elds: architecture, art, aeronautics, medicine, ³E Both the
new environment and the new applications were tested by visually
impaired people with different pro£les (congenitally
blind people, advantageously blind people, partially sighted
people,..) to evaluate the usefulness and potential of these
developments. The results of this validation con£rm the validity
and potential of the GRAB system for these kinds of
applications, although some features require some adjustments
to create future usable tools. An important achievement
was the improvement in the understanding of the interaction
process of visual impaired people with haptic environments.
This will be very useful for the development of
future applications in this £eld. In particular, having evaluated
three working applications of very different types has
enabled us to build a body of knowledge concerning the
£ner points of interaction in the virtual haptic environment.
This knowledge covers general interaction guidelines, the
differences between the virtual haptic environment and the
physical world and guidelines for taking into account speci£c
circumstances of the interaction, including the nature
of the happtic objects and the requirements of the tasks. Access
to computer-generated graphics applications via GRAB
system could potentially increase employment opportunities
and open up access to jobs which have hitherto been closed
to blind users and improve their education, teaching and