Traditionally, interaction with a computer has involved the use of a keyboard, mouse or joystick/trackball device to input information and the use of a visual display unit (VDU) to receive output from the system. With the development of Virtual Reality (VR) systems, new interaction methods have been developed that allow the user to step into computer generated ,or virtual, environments (VEs) which is achieved by immersing the user in the synthetic environment. This can be achieved by various means including the wearing of enclosed Head-Mounted Displays (HMDs) which may provide stereoscopic images of the VE and by tracking the motion of the head, hands, fingers, and other limbs of the body using magnetic or optical tracking systems. Ideally, it is desirable that tracked movements of the body are updated in real time, but limitations to the currently available technologies dictate that this is not always the case.
One of the greatest strengths of this new technology is that developers of VEs are not constrained by traditional limits. Kalawsky (1996) identifies a number of key advantages provided by VR techniques:
The potential applications of VR technology are vast and a great deal of research is currently underway in many commercial and academic institutions to develop these technologies into effective useable systems. However, a number of recent reports have raised concern that there may be a downside to the exploitation of this new technology, suggesting that users may experience physical, physiological and psychological side-effects after using this type of equipment. Many of the early reports received extensive media coverage, which in many cases was misleading, sensationalist and inaccurate. The purpose of this report is to highlight the potential side-effects that have been discussed in literature to date and to attempt to place them in the correct perspective. In this way, users and potential users of VR systems will have some indication of the side-effects that they may experience and the generally accepted reasons for their genesis.
Although VR is touted as a revolutionary new technology, the idea of inclusion within an artificial environment is not new. In fact VR can be considered an extension of ideas which have been around for some considerable time such as flight simulation, Sensorama (Heilig, 1962) and wide screen cinema (such as Cinerama and IMAX). Using such systems, the viewer is presented with a screen which takes up a large portion of the visual field giving a powerful sense of presence or being there.
Two major breakthroughs occurred in the 1960s with the arrival of the minicomputer and the work of Ivan Sutherland in 1965 entitled "The Ultimate Display ". In this paper Sutherland prophesied the development of the first HMD, which he was later to achieve with an HMD called "The Sword of Damocles". Sutherland also realised the potential of computers to generate images for flight simulation, where, previously images were generated using video camera.
These ideas were combined by two NASA Ames scientists, Fisher and McGreevy, working on a project called the virtual workstation in 1984. From these ideas NASA Ames developed the first commercially viable HMD, called the visual environment display (VIVED), which was based on a scuba divers face mask with the optical screen displays supplied from two Sony Watchman hand-held televisions. This development was unprecedented, as NASA had an HMD that could be produced at an affordable price and the VR industry was born.
VR research and development projects are currently underway world-wide in large organisations such as NASA, IBM, Intel, Boeing and Rolls Royce. To give some indication of the incredible flexibility of VR techniques, a number of current and diverse VR applications are listed below.
Amoco, in conjunction with Bravo Multimedia, have developed a simulator to evaluate the skills of their tanker drivers. The simulator is known as truck driVR, and uses an Intergraph PC and a Virtual Research FS5 HMD. When using the simulator, the driver is placed in charge of a Kenworth truck hauling 40,000 gallons of fuel. The simulation is made up of 21 events such as a deer crossing the road, a car backing out of a drive and an ambulance on an emergency call driving past and these events can occur on an urban or rural route. The driver is assessed on their ability to cope with the various events and all sessions are video-taped and reviewed with an instructor.
The systems are built into vans and taken around the country. The purpose is to develop a better system of driver evaluation than the one individual evaluation a year that Amoco currently employ. Truck driVR remains under development and is currently being offered to other fleet operators as a driver evaluation tool.
The Wilson Group, based at the University of California, San Diego are developing the Virtual Explorer learning tool. They are currently developing a Fantastic Voyage virtual environment that allows the user to shrink down to cellular scale and travel through the human vascular system, observing the interplay of the fundamental components of the immune system and the bodies response to foreign invaders. The purpose is "to interface real textbook biology and critical thinking with action, visceral response and fun."
The system uses three rear projection screens, placed at 60 degree angles to the front of the ship pod. Using stereoscopic display techniques, the screens are used to provide the users view of the virtual world. The experience is further enhanced by a combination of spatialized and ambient sound and motion input from the user is provided by a flybox.
An example of a VR application with a foot in many camps is the Virtual Stonehenge model developed by Intelä; and English Heritage. The application can be regarded as an educational, historical and architectural tool as well as an application that encourages virtual tourism.
The internet model of Stonehenge, which is scientifically accurate, can be explored by connecting a PC to Intels corporate site. Users can navigate the environment in ten different eras, stretching from as far back as 8500BC to 2000AD. They can also move forwards and backwards in time, approach the site from any angle or fly over the scene and can observe the site in daylight, moonlight and view a Solstice sunrise. The model also includes educational content pertaining to the prehistoric people who built it, the inspiration for the building of the monument and the techniques used in the construction of the site. The internet model was developed on a PC using Superscapes VRT authoring software. In addition to the internet model, English Heritage, in association with VR Solutions Limited of Salford, have developed a photorealistic VR model of Stonehenge using photographs of the stones and geographic information system (GIS) data of the surrounding landscape.
Further VR applications in more diverse areas include military applications such as Simulation Networking (SIMNET), the Virtual Solar System educational VE developed by Simon Nee at Loughborough University and VEs for entertainment such as the head-tracked PC version of Hereticä; by ID Software and public-space VR entertainment systems such as Total Recoilä; by Virtuality PLC.
The purpose of this report is to outline to members of the AGOCG user commumity the potential health and safety problems that have been associated with VR use in current research. It is envisaged that this information will be of particular interest to those considering purchasing VR equipment, particularly immersive systems. However, it is also intended that the report will be of use to those who already have VR systems of all types as many of the health and safety issues discussed can be related to a number of different VR implementations. The report will categorise VR system implementations into three main types: non-immersive, semi-immersive and fully immersive. The hardware required to deliver each type of implementation will also be discussed.
The potential side-effects that have been suggested in the literature will then be discussed. These will be grouped into three main categories : physical, physiological and psychological symptoms respectively. The relationship between these symptoms and the type of hardware being used will then be evaluated. The intention is to give some indication of the reasons for the genesis of particular problems (if those reasons are currently known) and the VR platforms one which one would expect particular symptoms to occur. Often solutions can be relatively simple as long as the system owner is aware of the genesis of a particular problem.
It must be stressed that this report is not intended to be an in-depth discussion of currently available VR hardware or an analysis of the complex causative factors involved in many of the side-effects that will be discussed. References to research will be provided in each section to allow the reader to investigate particular areas further if they wish. Further, the indication of a potential side-effect in this report does not validate it as an proven occurrence or indicate the authors agreement that such effects occur. The intention is to provide an overview of the literature that will allow the reader to attach the importance to proposed effects that they deem appropriate.
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