People experience the world around them, what we call “reality,” by receiving sensory input and processing these messages. Sources of sensory stimulus are greatly varied and include anything from sound waves picked up by your ears to the feeling of wearing socks. Because the basis of perception is founded on stimulation, manipulation of these inputs can effectively enable people to experience false sensations. A virtual world indistinguishable from reality—perfectly stimulating all senses—is the end-goal of researchers developing virtual reality interfaces.
Virtual reality (VR) refers to computer-generated simulation of a realistic or imaginary world that uses visual, tactile, and auditory cues to manipulate the user's sensations and perceptions. While VR interfaces usually include head-mounted displays that provide visual input, more sophisticated devices for simulating senses of touch, taste, smell, and sound are being researched. An important goal of VR research is attaining the ability to provide a highly realistic environment in which individuals can interact with their surroundings and receive sensory feedback. Unfortunately, due to the limitations of computing power and research in the field of VR, a program inducing complete immersion into the virtual worlds is not yet possible.
Although VR seems to be a technology borrowed from science fiction novels, it has actually existed in some fashion for eight decades. In 1929, Edward Link invented the first flying simulator, which used pneumatics to mimic aerial maneuvers and provided haptic feedback to the user. The Link Trainer, which initially gained popularity as an amusement park ride, later became a standard training module for U.S. pilots during World War II.1 The Link Trainer is a very primitive example of VR, as it leaves much to imagination; pilots would be hard pressed to believe they were actually within the cockpit of an aircraft during a dogfight and not in a cramped box, rocking back and forth. However, since its creation, the Link Trainer has promoted the idea that simulators could be utilized to recreate situations that would otherwise be difficult to experience.
The advent of computers initiated an explosion of advanced VR interfaces such as head mounted displays (HMDs) that allow the user to interact with the virtual world and receive enhanced sensory information. In 1991, Virtuality Group developed the 1000CS gaming system, which was a pioneer in the field of head tracking and enabled players to turn their heads to view their surroundings within the games they were playing.2 The 1000CS was an important first step for commercially available VR technology. Modern HMDs are much less bulky than their predecessors, less prone to causing neck cramps due to their lighter weight, and more responsive to rotation. Recent advances in virtual reality focus on providing as realistic an environment as possible. Higher resolution screens and faster computers are becoming cheaper to produce and more widely available, spurring the growth of VR.
While most interfaces prioritize visual and audio simulation, technologies are being developed that will be able to stimulate touch, taste, and smell to provide a highly life-like world. Researchers at the Universities of York and Warwick have presented a prototype of the Virtual Cocoon, a helmet that uses tubes, fans, and a high definition (HD) screen to fully immerse the user in what the team calls “Real Virtuality.”3 Another recent advance from the University of Singapore used “non-invasive electrical and thermal stimulation … [to] recreate the taste of virtual food and drinks.”4 Such technologies could lead to a perfect virtual environment that stimulates all of the senses. Additionally, this research introduces exciting possibilities such as virtually sampling a dish before ordering it at a restaurant or experiencing the feeling of snow on a hot summer day.
The last decade has seen both great advances in VR technologies and expansion into a wide range of practical fields such as military training.5 Although simulators have been used by the military since the simple Link Trainer in 1929, new methods of virtual simulation have greatly increased the diversity and immersion of training available. Soldiers can be placed in various virtual scenarios and learn the tactics and skills necessary in real combat, including developing assault plans on military targets, managing disaster and field casualties, and adapting to new environments.5,6 While it cannot replace field experience, VR serves as a useful tool to augment their training.
There are many projected uses for VR in the field of medicine as well. An experiment led by Dr. Patrice Crochet of La Conception Hospital in Marseille tested whether surgeons using a VR surgical training simulator could improve the quality of their surgical skills. Their findings indicated that VR training improved surgeons’ dexterity, supporting the claim that VR could potentially serve as a medical training tool.7 With the high number of annual medical malpractice deaths, using VR to provide doctors with practical experience is most definitely a useful tool.
Perhaps the most anticipated application of VR is its extension into video games and other multimedia. The Oculus Rift, an HMD currently in development, is a highly anticipated game system that incorporates HD graphics with high-fidelity head tracking to create a unique gaming experience.8,9 Combined with omnidirectional treadmills and directional audio, players may soon be able to engage in a highly realistic environment. Virtual controllers such as the Leap Motion—which uses sensors to process hand and finger motions as input data—are also being incorporated for further immersion and interactive capabilities. These VR technologies are not only limited to video games; virtual tourism or impossible real-world experiences such as flying could be simulated.
With ever-increasing computer processing speeds and extremely high resolution 8K displays in development, the future of VR holds great promise. Currently, VR is proving invaluable to military and medical training. A major limitation of VR is its inability to create perfect, interference-free environments due to inadequate hardware and software capabilities. However, these obstacles will be overcome as VR technology advances. Perhaps one day it will be impossible to distinguish between simulated reality and reality itself.
- Van Embden, E. Rare flight trainer can be found at Millville Army Airfield Museum / Link Trainer one of 5 working models in world. The Press of Atlantic City, Feb. 23, 2008, p. C1.
- Davies, H. Dr. Waldern’s dream machines: arcade thrills for spotty youths today, but revolutionary tools for surgeons and architects tomorrow, says the pioneer of virtual reality. http://www.independent.co.uk/life-style/ the-hunter-davies-interview-dr-waldernsdream-machines-arcade-thrills-for-spottyyouths-today-but-revolutionary-tools-forsurgeons-and-architects-tomorrow-says-thepioneer-of-virtual-reality-1506176.html (accessed Jan. 17, 2015.)
- First virtual reality technology to let you see, hear, smell, taste, and touch. www.sciencedaily. com/releases/2009/03/090304091227.htm (accessed Jan. 17, 2015).
- National University of Singapore. Simulator recreates virtual taste online.http://www.sciencedaily.com/ releases/2014/01/140102114807.htm (accessed Oct. 31, 2014).
- Bymer, L. Virtual reality used to train soldiers in new training simulator. http://www.army.mil/ article/84453/ (accessed Jan. 17, 2015).
- Virtual reality army training. http://www.vrs. org.uk/virtual-reality-military/army-training. html# (accessed Oct. 31, 2014).
- Crochet, P. et al. Ann. Surg. 2011, 253, 1216-1222.
- Corriea, A. Oculus Rift HD drops you into a world so real it hurts. http://www.polygon. com/2013/6/14/4429086/oculus-rift-hd-e3 (accessed Nov. 9, 2014).
- Oculus Rift. https://www.oculus.com/ (accessed Jan. 17, 2015).