Environmental Engineering Reference
In-Depth Information
These evidences showed the usefulness of virtual environments for rehabilitation therapy to
improve movement performance and/or functional ability and add to other research efforts
such as the study of computerized training in a virtual reality environment as an
enhancement to existing methods of retraining the hand in patients in the later phase of
recovery after a stroke (Merians et al., 2002), robot training using a virtual environment to
enhance stroke rehabilitation (Krebs, Hogan, Aisen & Volpe, 1998), and Professor Baram's
work on a virtual reality device that helps Parkinson's and stroke patients walk better
(Garbi, 2002). Curtis (1998) and Merians et al. (2002) observed that the field of virtual reality
was still in its infancy, especially for special needs; however, crossovers with fields such as
computer graphics, Computer-Aided Design (CAD), acoustics, and human-computer
interface, which are much better established, are currently making the creation of virtual
environments more viable. Advances in technology, in terms of computer processing power
and graphics hardware, have made it possible to create virtual environment on cheap
computer platforms (e.g., 486 or Pentium IBM compatible PCs). These were previously only
possible on high-end workstations such as silicon graphics machines. Breakthroughs in LCD
technology are already being delivered in the form of cheaper and higher resolution virtual
reality headsets, which are required for fully-immersive virtual environment. Global
Positioning Satellite (GPS) technologies, such as compact gyroscopes, promise mass
production of three-dimensional (3D) input devices, similar to those already found in the
Phillips 3D mouse, to facilitate interactions at a very low cost, and fields such as Human
Computer Interaction (HCI) have long been focused on the use of virtual reality as an
alternative means of interaction (Snowdon, West & Howard, 1993). Telecommunication
networks currently can deliver via the Internet high bandwidth graphical information
required by virtual reality, and technology solutions are now being implemented using
virtual reality for special needs (Boian et al. 2002; Smythe, Furner & Mercinelli, 1995). Web
page designs can now utilize 3D capabilities using the Virtual Reality Mark-up Language
(VRML), and the ability to extend healthcare's reach has been advocated (Plant, 1996).
3. Forms of virtual environments
Virtual environments are generally classified by the degree of immersion it provides
through level of user interactivity, image complexity, stereoscopic view, field of regard and
the update rate of display. A careful and complex combination of all these factors determine
the level of immersion achieved as no one parameter is effective in itself.
3.1 Fully immersive environments
Virtual Environment can be fully immersive, where, in this sense, the user feels they are part
of the simulated world. All the senses of the user are engaged, sight, sound, touch, smell,
taste, with technology such as panoramic 3D displays for full sense of vision, surround
sounds for auditory immersion, haptic and force feedback for tactile feelings, and smell and
taste replications for olfactory and gustation experiences. This form of environment. Fully
immersive environments provide the most direct experience of virtual environments and
have been reported to be probably the most widely known VR implementation where the
user either wears a Head Mounted Display (HMD) or uses some form of head-coupled
display such as a Binocular Omni-Orientation Monitor or BOOM (Bolas, 1994).
