04-07-2012, 12:51 PM
INTERACTING WITH EYE MOVEMENTS IN VIRTUAL ENVIRONMENTS
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ABSTRACT
Eye movement-based interaction offers the potential of
easy, natural, and fast ways of interacting in virtual
environments. However, there is little empirical evidence
about the advantages or disadvantages of this approach. We
developed a new interaction technique for eye movement
interaction in a virtual environment and compared it to
more conventional 3-D pointing. We conducted an
experiment to compare performance of the two interaction
types and to assess their impacts on spatial memory of
subjects and to explore subjects' satisfaction with the two
types of interactions.
INTRODUCTION
Virtual environments can now display realistic, immersive
graphical worlds. However, interacting with such a world
can still be difficult. They usually lack haptic feedback to
guide the hand and to support it in space. We thus require
new interaction techniques to provide users with easy and
natural ways of interacting in virtual environments. This is
particularly important for dealing with displayed objects
beyond the reach of the user’s arm or the range of a short
walk. Some recent studies have focused on developing
interaction techniques using arm, hand.
EYE MOVEMENT-BASED INTERACTION IN VIRTUAL
REALITY
Eye movement-based interaction is an example of the
emerging non-command based interaction style [14]. In this
type of interaction, the computer observes and interprets
user actions instead of waiting for explicit commands.
Interactions become more natural and easier to use. One
system that suggests such advantages is a screen-based
system developed by Starker and Bolt [18]. It monitors eye
movements of the user, interprets which objects attract the
user’s interest, and responds with narration about the
selected objects. It minimizes the physical effort required to
interact with the system and increases interactivity. High
interactivity is even more important in VR applications
where users often deal with more dynamic and complex
environments.
A NEW INTERACTION TECHNIQUE
Using natural eye movements in virtual environments
requires development of appropriate interaction techniques.
In this study, we developed an interaction technique that
combines features of eye movements and non-command
based interactions in a virtual environment. Our objective is
to enable users to interact with eye movements, without
explicit commands where possible. However, we should
also avoid the Midas Touch problem, i.e., unwanted
activation of commands every time user looks at something
[9]. Our approach here was for the computer to respond to
the user’s glances about the virtual environment with
continuous, gradual changes.
DISCUSSION AND CONCLUSIONS
By developing an interaction technique that allows the use
of natural eye movements in virtual environments, we were
able to compare the performance of eye movement and
pointing based interactions in close and distant virtual
environments. The results show that interaction with eye
movements was faster than interaction with pointing. They
further indicate that the speed advantage of eye movements
was more significant in distant virtual environments. Our
findings suggest that eye movement-based interactions
could become a viable interaction type in virtual
environments provided that proper interaction techniques
are developed.