© Mark Platten 2006
Chapter One: The Mechanics Of Virtual Reality
To provide a truly convincing virtual reality, the five senses must ideally be confronted with detailed information about this environment. Similarly information about the participant must be effectively obtained.
Figure 2. (overleaf) illustrates the essential VR principle.
FIG.2 THE CYBERNETIC FEEDBACK LOOP(2)
The 'puppet' monitors the physical, 'real' world through an assortment of sensors, and acts on the physical world through various effectors; or output devices. Sensors might include tracking devices to monitor a persons spatial position and orientation, keyboards, joysticks, steering wheels, pressure gauges, voice recognisers, etc. - in fact any device capable of picking up information from/about its user. Conversely, the effectors transmit information back to the user - they include various forms of graphic and video display, sound generators, resistance controllers, motion platforms, force feedback devices, etc. The puppet gives the patron a virtual body in so-called cyberspace; and the patron gives the puppet a personality. The more sophisticated the arrangements of sensors and effectors, so the more sophisticated the interaction between the user and the virtual world.
My first hands-on experience of so-called Virtual Reality came during Summer of this year, when I tried the 'Virtuality' system installed in the Trocadero Centre, Piccadilly, vaunted as a national first. 'Virtuality' comes courtesy of a Loughborough based firm, W Industries, who have commercially developed what they claim is the world's first video arcade game based on VR....
I have to ask myself what I actually wanted. Perhaps I have been seduced by all the hype, and the £2 fee into thinking I am about to have a mind-blowing experience.
- It is good, but not overwhelmingly so.
I am very conscious of sitting with a foolish-looking helmet on rather than sitting in a speeding vehicle on a racetrack. Nevertheless, it is doubtless sublime within machine arcade criteria. I remove the rather clammy headset, and step out of the machine. I keep reminding myself that the shortcomings I have noted with this Virtuality system are those of sheer sophistication of hardware; it just needs faster processing, greater memory, better interfacing and improved graphic resolution, all of which will unquestionably improve with time as computer manufacturers begin to vie with each other over product performance. The concept is sound. Within its limitations it does actually work; I was able to function as though I was actually there, wherever 'there' might have been. The supervisor who helps players in and out of the machines told me the game was attracting considerable attention; certainly a lot of money looked to be made......
Despite the sublime electronics running the VR process, it is the physical interface hardware on which the success of VR will stand. How faithfully will the hardware be able to reproduce the experiences purporting to be reality?
From Victorian zoetropes, the animated image has evolved through various mediums: the moving series of celluloid images at 24 frames per second known as cinema; cathode ray-tube TV, next, thanks to the intriguing shapes and exotic behaviour of liquid crystals, and demand for portable 'lap-top' computers, has become a flat gas plasma/LCD screen small enough to be worn in front of the eyes to give a stereoptic effect, and still the R&D continues. I was not greatly enamoured of my experiences in commercially available head-mounted displays. Howard Rheingold discusses the latest research...
Even from description, the idea of an entire room becoming screen becoming environment is appealling, especially when combined with the 3D effect. (Fig. 5b). I had wondered why there seemed to have been little interest in holographics; in fact I did not recall coming across any mention of the hologram during the course of my research, despite the obvious striving for realism in three dimensions VR is concerned with, until I saw product at CG91, the annual computer graphics trade show. Here, was evidence of such lenticular lenses, which offered a peculiar but superior effect to a conventional flat screen. Again, technology is doing its leapfrog act :
The Virtuality system's sound effects were disappointing. A shame; 'perfect' sound reproduction is a goal that audio researchers and manufacturers have been striving toward for many years, and are now capable of achieving impressive results. Quadraphonic hi-fi failed through practical rather than technical reasons - it was not successfully turned into a market - viable alternative to stereo, with insufficient recorded product available to play. Similarly, binaural, or dummy head recording, which as the name implies, utilises two microphones placed appropriately within the ear cavities of a facsimile human head to record sound within a studio, whilst more effective than normal stereo, stumbled over its being only effective when played back through headphones.
'Humans hear spatially....the separation and shape of the ears enables us to determine the location of a sound event from all directions... computer-generated spatial sound is feasible with current technology with some minor compromises.The computational expense of generating echo distance cues remains a limiting factor in 3D sound realism, however, this problem goes away as speeds increase and hardware becomes more accessible' (5)
The music hardware company Roland this year launched the RSS 3D Sound Processor (Fig.6). The technical details demand a dissertation in their own right, suffice to say that by exploiting effects that occur in nature - doppler distortion; the relative incidence of sound arriving at ears a calculable distance apart, and frequency fall-off, a sound system has been developed that operates feasibly with just two loudspeakers, though it currently commands a price of £25 000. Demonstrated on 'Tomorrow's World' with a simultaneous FM broadcast, despite less than ideal circumstances the 3D effect was clearly discernible, although listening to the recording now, 'phasing' is evident.
- Chris Currell, LA musician with special interest in 3D sound (7)
So it seems that Virtual Reality, limited to the sense of sound and vision, has been effectively realised, and will steadily improve as time goes by. Current major limitations reside with physical; tactile, sensation, and smell and taste...
(1) Kreuger, Myron, 'Artificial Reality : Past & Future', in 'Virtual Reality', Meckler Publ., 1991, p.19