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| Home >> Index Pages >> Informational Pages >> Discount Computer Systems >> News >> Collection of Essays from Scholarship 2007 >> |
Chris Covington- by Chris Covington Introduction to Virtual Reality What would it be like to explore life under the ocean without getting wet? How about walking through the great pyramids as they are being built? Such feats are difficult to imagine, let alone accomplish. However, with the use of "virtual reality" (VR), such things can be artificially emulated. The idea of commonplace virtual reality is one that has been firmly implanted in fantasy and science fiction for years. Instances of virtual reality applications are varied and numerous. From the ideal "holodeck" presented in the Star Trek series, to the modest apparatus shown in the movie The Lawnmower Man, most occurrences of virtual reality in works of fiction aspire to be perfect solutions. While the holodeck may be many years away, virtual reality itself is already here. In the basic definition, virtual reality provides an immersive artificial environment. Through the use of specialized equipment which will be discussed later, people can have experiences which may not be available to them in real life. From scientific visualization, to entertainment, even physical rehabilitation, virtual reality has nearly limitless applications. Virtual vs. Augmented Reality No discussion of virtual reality would be complete without addressing the similarities with augmented reality. Augmented reality (AR) is often confused and commingled with virtual reality, but the two serve different purposes. In virtual reality, the user is completely immersed in a virtual environment. Interactions within a virtual reality environment typically have little or no impact on the real world. As discussed later, this is accomplished by hiding or replacing the real world with a virtual environment. Augmented reality works by providing the user with more information than would normally be available in the real world, thus "augmenting" reality. The method of augmentation depends on the task being performed. Common AR devices and implementations include transparent heads-up displays (HUD's), handheld computers and other ubiquitous computing hardware. Effectively, VR hides reality, but AR adds to it. Additional information on augmented reality and its applications is outside the scope of this discussion. Hardware Virtual reality is first and foremost an alternate method of providing visual feedback. Standard graphical displays are already commonly used for visualization and entertainment, so what is different with VR? In order to understand how virtual reality functions and how it differs from other display techniques, including augmented reality, it is necessary to examine the underlying hardware. The hardware used for virtual reality simulations can take many different forms depending on the application, but typically this hardware can be categorized into three different types. Head-Mounted Devices The most portable form of VR utilizes head-mounted display devices. While this device category encompasses all forms of head worn device, there are still several different types. These devices can range from simple "goggles" that only obscure the wearer's vision, to completely enclosed helmets. In effect, head-mounted devices can be described, in most cases, as head-mounted monitors. While there are differences between manufacturers and models, most head-mounted devices contain either a single or dual display screens. These screens provide the visual representation of the virtual environment. By using screens which can be treated as regular computer monitors, albeit at lower resolutions, using head-mounted display devices for VR applications becomes much simpler. The earliest head-mounted display devices were hardly small or mobile, which made them prone to nicknames such as Sutherland's "Sword of Damocles" due to its enormous size. However, as technology has improved, head-mounted displays have shrunk to more manageable sizes. Because of their small size and relatively low cost compared to the other VR devices listed below, head-mounted devices are also the most common. There are many manufacturers who make this kind of device readily available to the public. The low cost and ease of use enables these devices to be used in a wide range of applications. A drawback to the use of head-mounted devices is the fact that they are not self-contained. In other words, they must be connected to a display controller or server of some sort, which provides the images displayed to the user. In the past, this was done by directly wiring the device to the controller. By doing so, the user's mobility is severely restricted for both connectivity and safety reasons. With the advent of reliable wireless communication and its continuing improvements, head-mounted devices no longer need to be tied directly to a controller. While this may allow the user more mobility than in the past, it can also present new challenges that must be addressed as well. Some of these challenges, such as increased disorientation, are detailed later. As previously mentioned, safety is a concern with the use of head-mounted displays, particularly more portable forms. When a user's vision is completely obscured, that user can easily lose touch with the surrounding environment. In a virtual environment where the user is expected to "move" around, obstacles in the real world can be hazardous if the user were to run into them. To prevent injury, the user needs to be kept from running into unknown obstacles. Movement may also need to be restricted for application based reasons. There are effectively two methods to restrict movement while using head-mounted devices. The first is to actually prevent the user from leaving a specified, controlled area. Early commercial attempts, such as the Virtuality system, simply kept the user stationary within a confined area. This does prevent the user from getting hurt, but it also prevents the user from moving. Recently, work has been done to combine the movement aspect of interaction with the safety of restricted movement. The VirtuSphere, for example, uses a "hamster ball" style cage to contain the user's movements, but allow the user to move around almost as if the environment was unconstrained. Instead of restricting the user's movement, it is also possible to restrict the movement of the head-mounted display. By fixing the head-mounted display in a stationary or limited position, the user’s movement is automatically restricted. In this case, the user cannot move outside the range of motion allowed by the fixed head-mounted display. The Global VR Vortek machines, discussed in the applications section below, use a boom arm to accommodate this movement restriction. Simulators Considerably larger than a simple set of goggles, simulators are usually self-contained apparatuses designed for a specific purpose. Simulators tend to be completely enclosed in order to seclude the user from being distracted by the surroundings. Within the simulator itself, is any number of display devices (e.g. monitors, gauges, etc.) and controls for input. Some simulators take the virtual environment experience a step further and incorporate full or partial motion of the simulator. Such motion can include up to 6 degrees of freedom (DOF) and can provide a reasonable facsimile of motion in the virtual environment. By including motion in the virtual experience, it becomes more complete and enables the user to feel absorbed in the experience. With head-mounted displays, the same device can be used for many different purposes easily. Simulators, however, are designed for a certain simulation experience and are difficult to repurpose. Additionally, due to their enclosed nature and in order to accommodate any motion capabilities, simulators can be considerably large in size and cost. Because of this, simulators are not commonly found outside of larger arcades and amusement parks. Immersive Environments A common misconception is that using virtual reality requires cumbersome equipment or requires the restriction of the users' movement, as is the case with the preceding hardware. While it is true that the VR devices mentioned previously can severely restrict the user's mobility in some way, there are ways of providing virtual reality experiences in an open environment. Using an open environment allows a higher level of interaction and collaboration than is possible in a more restrictive system. The CAVE system is one such environment. This type of environment can be created by using multiple display devices operating within a closed area. The display devices in an environment like this operate in conjunction with each other to provide a cohesive environment and are typically projection based. Having an open virtual environment allows people to interact with the environment, and each other, unencumbered by awkward or restrictive devices. While there is nothing preventing multiple individual VR systems from being linked together into a single cohesive environment, it can be difficult for users to interact with avatars instead of real people. When humans interact with each other, words, hand gestures, facial expressions and other body information is communicated. By keeping users from being hidden by VR apparatuses, it can help to facilitate interpersonal communication between those participants. Input Devices A point that has been glossed over thus far is that virtual reality applications need some form of input. Minimally, directional input is needed unless the application is completely outside of the user’s control. Depending on the VR application, additional methods of input may be necessary. There are many different styles of input devices, most of which depend on the presentation devices used. A common pairing with head-mounted displays is a simple handheld joystick. A simple device is necessary in this case since the user does not have the ability to look at his or her hands without removing the head-mounted display. In other situations, the input device(s) is typically catered to the virtual environment. For example, in a flight simulator, the input device may be mockups of a functional cockpit instrument panel. For large immersive environments, some input devices may be fixed in scattered locations around the environment, while others may be carried by the participants. A developing field which may have future applications in virtual reality is that of recognizing hand gestures. Hand gestures, such as pointing at an object with your index finger, are a natural method of interaction and communication between humans. Currently, research is being conducted into ways of analyzing hand gestures in real-time and utilizing those gestures as input for various applications. It is not difficult to see that hand gestures could replace other input devices for VR applications. An additional consideration for virtual reality applications is the ability to track the user's body and head movement and correlate them with the user's perspective in the virtual environment. For cases where the user is completely immobilized, such as in a simulator, the user's virtual perspective is typically directly controlled by the input device or the application, not the body or head movement. When the user's movement is not as restricted, with head-mounted displays for example, the user's body or head movement must be tracked. Tracking a user's movements can be done in numerous ways and depends on what is to be tracked. For example, if only the position of the user's feet is important, then specialized footwear can be used. A more common occurrence, however, is tracking head movement. To easily accommodate this functionality, many head-mounted displays incorporate head movement tracking. Applications It is important to understand how the underlying hardware for virtual reality works before examining the actual applications. Different applications may require different forms of VR hardware. Now that the hardware foundation has been covered, discussion can turn towards some of the diverse applications that virtual reality can be used for. Visualization Numerous applications use different visualization techniques to display and detail different types of information. Most of these techniques use simple display devices, such as standard computer monitors, for their ease of use and common availability. However, the simplicity of these devices can limit their functionality when it comes to certain visualization techniques. A common problem with devices like monitors is that they are limited to presenting two dimensional images. Virtual reality can help alleviate this problem and open up new opportunities for visualization. By using virtual reality, a fully interactive three dimensional environment can be presented. Scientific applications can benefit greatly from the enhanced level of detail. In a wind tunnel simulation, for example, it can be difficult or impossible to exactly how air flow passes over an object. A virtual reality simulation can allow a user to walk around an object and see the air flow firsthand. Not only that, but VR also allows the possibility of direct object manipulation, allowing dynamic changes in the simulation to be viewed in real or pseudo real-time. Education In the past, museums and other institutions began implementing forms of augmented reality to either replace guided tours or to add to them. These methods have included such items as audio tours to replace the need for guided tours. Eliminating the necessity for guided tours through these devices gives freedom to museum patrons while still providing more information than normal. Through the use of virtual reality, visits to a museum can be eliminated completely. Additionally, VR allows the exhibits to be interacted with on a level previously unheard of without the risk of damaging priceless artifacts. Extending the museum-like experience, virtual reality has been applied to interactive storytelling for educational purposes. By allowing kids or students to interact with a detailed virtual environment, they are able to pick and choose which areas of the "story" to get more information about. High levels of direct interaction can lead to higher levels of understanding and comprehension. Rehabilitation An emerging trend in virtual reality is its use for physical rehabilitation. Virtual reality has the ability to present diverse and unique situations very rapidly. This ability can be extremely useful for diagnosing, and in some cases curing, various ailments. A novel approach currently being researched is the use of virtual reality to help people with balance disorders. VR allows doctors to rapidly vary conditions and target specific situations to treat or diagnose patients. While these conditions and situations may not be difficult to physically recreate, a patient may require multiple different scenarios. In order to achieve the desired results, rapid switching from one scenario to another may be required. Depending on the scenarios require, the transitions may not be able to be made quickly or easily. Games & Simulations When people think about uses for virtual reality, inevitably entertainment is one of the first to come to mind. From video games to simulated roller coasters, entertainment applications are a perfect showcase for virtual reality. Some of these methods of entertainment are detailed below. Game designers are constantly attempting to make video games more realistic, both visually and interactively. Because of this, one of the forefronts of virtual reality applications has always been its use in video games. Virtual reality based games take many forms and can be regularly found in arcades. The popular Vortek series of arcade games from Global VR is one of the definitive demonstrations of how virtual reality can be effectively used for a video game. The system works by using a head-mounted display and controls integrated into a helmet. The helmet is then attached to an adjustable boom arm, allowing these arcade quality games provide a virtual reality experience with almost no setup time. A player simply has to put his or her head into the helmet, adjust the height for comfort, and play. While the boom mounted helmet restricts a player's movement to a small, circular area, it also allows players to quickly disengage the machine just by taking off the helmet. It would be difficult to argue that roller coasters and other rides at amusement parks are not popular attractions. Unfortunately, the shear size and cost of some of these rides prohibits them from being built except at a relatively small number of locations. A side effect of this is that not everyone can afford the time or money it takes to travel to these parks. Others may have physical difficulty riding a real amusement park ride. A natural consequence of these problems is that such popular rides would be transformed into virtual reality attractions. The considerably smaller size and cost, in comparison to a full amusement park ride, allows virtual reality simulators to be deployed in many more locations. Even within actual amusement parks, virtual reality attractions like Star-Tours are becoming a common sight. Aside from purely entertainment based simulations, such as virtual roller coaster rides, other forms of simulations also regularly use virtual reality to provide a better experience. Particularly in the military, virtual reality can be used for replacing real life situations where real injury or loss of life could occur. The veritable flight simulators, while also used as a form of entertainment in some places, are one of the most widespread simulations of this type. Issues and Concerns While virtual reality has numerous beneficial applications, there are some considerations that need to be made before it can be used. Some of these issues, such as the required space, can be designed around when planning an application. Other issues may not easily be accommodated by design changes, but need to be accounted for nonetheless. Size and Cost Standalone head-mounted displays are necessarily small. If this were not the case, then users would become fatigued simply by wearing the devices. However, the same cannot be said for other forms of VR hardware. As previously stated, some VR hardware can take up quite a bit of room. Immersive environments are, by nature, large encompassing spaces. In order to create a workable area, these environments must be large enough to allow the users to properly move around and interact with the virtual environment. Due to the size needed, these environments are difficult, if not impossible to relocate and requires a large empty space for setup. Simulators, while being smaller than enclosed environments, also have space considerations. If motion capabilities are included in a simulator, not only does space need to be allotted for the machine, space also needs to be allotted for the full range of motion. Otherwise, the device may not be able to achieve its full motion range. The device could also cause property damage or injury if it is not properly placed or given enough room to work in. The specialized nature of virtual reality hardware is also a concern for cost reasons. As hardware is refined and produced in large quantities, the cost of making it decreases. A good example of this is the rapid decline in the price of LCD monitors as they became more popular. Even though virtual reality devices are becoming more and more common, they are still not considered to be mainstream hardware. Because of this, specialized VR hardware maintains a higher cost in comparison to standard "off the shelf" computer components. User Safety A major concern with the implementation of virtual reality hardware and applications has so far only been touched briefly. The problem in question is that of safety. For any application, the safety of the user is something that always needs to be taken into account. With certain virtual reality setups, especially those incorporating head-mounted displays, the user's vision of the real world is obscured. If the user is expected to move around, then obstacles that are in the real environment, but not represented in the virtual environment, can present safety hazards. Even when a user is aware that unseen obstacles are present, there is an increased risk of those obstacles causing an accident. Aside from obscured vision, the user may face a potential hazard from the virtual reality hardware itself. Full-motion simulators typically suffer from this problem. Since users are completely enclosed by such devices, injuries can be caused by excessive jarring movements or the lack of proper restraints. The people using VR devices are not the only ones at risk. Especially with motion enabled simulators, those people in the immediate area also may be at risk. Sudden and unexpected movements of an active participant or a piece of VR hardware can easily cause injury to surrounding people and property. With the potential for constant and varying movement of the user, disorientation is also a potential problem. It is important that the feedback received by the user is updated quickly enough that any discernable differences between the virtual environment and what the user expects are minimized. These differences can cause disorientation and motion sickness if they are not carefully controlled. Interactivity The entire point of using virtual reality is to present an enhanced environment. Disregarding those applications where the user is not supposed to have any control, such as simulated roller coaster rides, it is necessary that the user has some level of control over the state of the virtual environment. The amount of user control varies from application to application, but is something which deserves proper consideration. Control is not necessarily limited to movement within the virtual environment. Aspects of the environment may be interacted with by the user. Such interaction needs to be carefully employed to account for the uniqueness of virtual reality. Similar to one of the concerns with safety, users may not necessarily be able to see where their hands are pointing in the virtual environment. Methods do exist to compensate for this, such as tracking hand movement and gestures. Conclusion Virtual reality presents a valuable opportunity for application designers. It allows a level of immersion and interaction which is unable to be achieved with other forms of presentation. However, while VR can be a valuable tool, concerns over certain aspects need to be considered before it is implemented. References: | Directron.com College Scholarship | Related Items: | Cirrus Foroughi | Jack Salamanchuk | Jennifer Furtado | Jennifer Story-Salacup | Jie Li | Maria Khan | Paul Frederick | Shawna Harpole | Steven Li | Veronica Muo | |
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