What enables a virtual reality headset to create a three-dimensional perspective for the user

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Making Reality Virtual: How VR “Tricks” Your Brain · Frontiers for Young Minds

Virtual reality (VR) can seem like being magically transported to a different world. It is an exciting technology but, after we put the headset on, we rarely stop to ask: how and why does it all seem so realistic? In this article, we are going to explore some of the concepts and techniques that make VR so convincing. We will discover that VR is effective because it mimics the experiences we encounter and the qualities of the real world around us. Our eyes and ears work the same whether we are in a real world or a virtual one. When we simulate the way we experience the real world—for instance, by simulating three- dimensional scenes using stereoscopic vision—VR can make us feel like as if we are in a different world altogether, but a very realistic-feeling one. After reading this article, you will have a basic understanding of what happens in VR. In short, you will have a sense of how VR technology is designed to tap into the way our brains work each day. You will see how VR tricks our brains to believe that we are somewhere else entirely, in interesting and sometimes unexpected ways.

Abstract

Virtual reality (VR) can seem like being magically transported to a different world. It is an exciting technology but, after we put the headset on, we rarely stop to ask: how and why does it all seem so realistic? In this article, we are going to explore some of the concepts and techniques that make VR so convincing. We will discover that VR is effective because it mimics the experiences we encounter and the qualities of the real world around us. Our eyes and ears work the same whether we are in a real world or a virtual one. When we simulate the way we experience the real world—for instance, by simulating three- dimensional scenes using stereoscopic vision—VR can make us feel like as if we are in a different world altogether, but a very realistic-feeling one. After reading this article, you will have a basic understanding of what happens in VR. In short, you will have a sense of how VR technology is designed to tap into the way our brains work each day. You will see how VR tricks our brains to believe that we are somewhere else entirely, in interesting and sometimes unexpected ways.

Making VR Feel Real

Virtual reality (VR) environments can be as small as the cockpit of an airplane or as large as an entire virtual world. These environments are designed to be as realistic as possible. ImmersionHow well virtual reality is able to mimic or simulate the real world as we know it. refers to how well technology can simulate the ways we sense and perceive the world in our everyday life. VR is considered when our experience in a virtual world is similar to our experience in the real world. In the real world, for example, you can walk or run at different speeds. If you were in a virtual world and you could only move at one speed, then the virtual world would not be immersive because your experience in VR would not match up with your experience of the real world, where you can walk or run at varying speeds. The technology behind VR is designed to make us feel like as if we have left the place we are standing and have been transported somewhere completely different. The more convincing (or immersive) the virtual world is, the more we start believing—or at least feeling as if—we are in the virtual environment. So how does this happen? Let us imagine that we are going to build an alternate universe for a friend to experience; it needs to be very convincing for us to succeed. If we get it right, then our friend’s brain will be “tricked” into sensing that this universe we have designed feels real, even though she knows, of course, that it is an illusion. If we get it wrong, our friend’s experiences in the alternate universe will fall short of how her brain would perceive (or interpret) things in the real world. She might think the experience is enjoyable, but her brain will not be “tricked” effectively. A third possibility is that we get it really wrong. This last scenario could mean that our friend experiences cybersicknessA feeling of disorientation and/or nausea that can result from the illusion of moving through virtual environments. These unpleasant sensations can also be caused by lagging (or delays) between what your vision expects and what the virtual world presents., which is when VR tricks your brain into feelings of motion-sickness (that queasy feeling some people get in a car, plane, or on a boat). In other words, VR is ineffective when the virtual world “behaves” differently than the real one.

How VR “Tricks” Our Brain

To understand how effective VR works, we first need to understand a little about how the brain makes sense of the world around us. Let us stop and think about the senses that allow us to experience the world: vision, hearing, and touch, to name a few. To make sense of the world, the brain needs to first bring in information from sensory organs, such as the eyes, ears, and skin. But bringing in the information only describes sensationThe different ways our body has of bringing us information about the world around us (for example, vision, hearing, touch, and taste), and the act of sending that information to our brain to perceive.—the act of transmitting information from the sense organs to the brain. What happens next is that the brain interprets this information, allowing us to understand what is happening in the environment. The brain’s interpretation of the senses which create our understanding is called perception

The process of our brain interpreting our senses into experiences.

How Ingredients in VR Can Cook up a Kind of Reality

There is a lot to keep track of if we are to construct an alternate universe! Because our senses are numerous and complex, we will discuss a simpler example—an alternate universe that we can experience through vision alone. We can still make this place convincing because our brains tend to rely more on vision than on any other sense. Let us imagine that what we create is something like a Martian dune (Figure 1). How do we start with this simple image and get our friend to perceive it as an immersive environment? For starters, our friend needs to be able to experience this two-dimensional image of a Martian dune as though it were as real as the three-dimensional space you are in right now. To make this happen, we will need to begin by building something into our environment called .

A typical photograph is a motionless picture viewed from a single perspective. In the real world, however, when we view a scene we can move around and look at things from different angles. In Figure 2, we have Leika the dog, sitting by a chair. We can sometimes see more of the chair than we can see of Leika, depending on our particular vantage point. How much our view of Leika is blocked by the chair depends on where we are standing. It is also important to note that we get a sense of depth in these pictures. In the photos, we can tell that the chair is (usually) closer to us than Leika, because it partially blocks our view of her. Knowing how close or far away things are partly depends upon our having binocular vision

Our left and right eyes are in slightly different positions on our head, and our brain is able to merge these two perspectives together much like looking through binoculars.. Binocular vision means that our left and right eyes see things from slightly different viewpoints, because they are located on different sides of the face. This means that our brain has to merge together information from these two perspectives. This process is called stereopsis

Seeing in stereo. How our brain combines visual information from our left and right eyes into one single image.

How to Create a Virtual World

So how do we create stereoscopic vision for our friend’s virtual experience? First, we need to get her a VR headset. VR headsets simulate binocular vision by presenting slightly different images to each eye, giving the illusion that a two-dimensional picture is a three-dimensional environment. Advanced VR headsets can be expensive, but you can make an inexpensive one at home with and then use a mobile phone as the presentation screen (using apps that split the image into separate views for each eye).

Seeing in stereo is not the only thing we will need, because our friend will want to look around at her surroundings the way we do when we are exploring a new place. So, we need to introduce the idea of -. Imagine walking into a beautiful cathedral. Chances are you will look up and down, left and right, and even behind you. In the real world, this happens so naturally that we do not even notice. However, in discovering how to create a VR environment, we often need to stop and question things that we usually take for granted.

What would happen if our VR headset always showed the same piece of the picture no matter how far up or down we looked? It would not be terribly convincing! An unconvincing virtual environment is just what we would get if we forgot about the head-tracking component of VR. When our friend looks up or down, the angle of the Martian dune should match the angle her head is pointed. When she turns around, the immersive environment needs to show her the visual information that was previously “behind” her. Head-tracking simply monitors the direction that your head is pointing by using something called an accelerometerA device that can tell whether (and in what direction) something is moving., which can sense whether (and in what direction) something is moving. Smartphones have accelerometers built into them by which you are able to enjoy certain types of games that involve tilting your phone. The phone’s accelerometer detects how you are tilting it and then adjusts your movement in the game accordingly.

Virtual Reality Gone Really Wrong

Accelerometers in VR imitate the “accelerometers” we carry around with us in our heads. Any time we move our heads, sense organs in our inner ears—the —provide the brain with information about how our head is oriented in space. The vestibular system is crucial for helping us maintain balance, making sure we do not fall down, and letting us know if we are lying down or standing up. Building head-tracking into our friend’s VR headset will make the virtual environment convincing if we get it right. But if it goes wrong, then our friend could get something called . Cybersickness happens in VR when a person feels disoriented and nauseous. It is like the kind of motion sickness you might get while trying to read a book in the backseat of a car. Interestingly, however, motion sickness and cybersickness are not quite the same thing. A closer look at the difference will help us understand how VR can be so successful at “tricking” the brain, sometimes in the wrong kinds of ways.

What happens when we get motion sickness? It is the result of the brain receiving two conflicting signals. One signal comes from the eyes and the other from the inner ears (specifically, the parts that sense how your head is tilted in space, not the parts that detect sounds!). If you are trying to read a book in a moving car, your eyes convey to the brain that you are not moving, but your vestibular system registers the movement of the car as it leans into the turns, brakes, and accelerates. Your vestibular system sends your brain information that you are moving. Your brain cannot always quite reconcile these two contrary messages, and sometimes the result is motion sickness. This is partly why staring out the window can help relieving motion sickness. By having your eyes send “we are moving” signals to the brain, there is no longer disconnect between the messages from your eyes and ears, and you start to feel better.

So, how is it possible to feel motion sick in VR when you are not moving at all? Your vestibular system generally is not highly activated in VR, because you are often either standing still or sitting. But, stereoscopic vision and head-tracking give you the illusion of moving. Cybersickness is thought to result from this illusion, also known as . You might have experienced a vection illusion if you were ever on a train or bus and thought you were moving forward or backward when it was in fact the vehicle that was moving. This illusion can arise in VR, because when moving through virtual space (using a game controller, for instance), your eyes say, “I am moving,” whereas your vestibular system says, “I am staying still.” Cybersickness can also occur when there is a time delay between when your head moves and when the screen adjusts the perspective of the environment. Some people are particularly prone to motion- and cybersickness, though the exact reason for this difference between individuals is not yet known [1].

Just How Real Does VR Feel?

Let us assume we have got the components of our VR headset correct and that our friend is not prone to cybersickness; we have pulled off a successful virtual environment, but how do we know how real it feels? PresenceHow convincing we perceive a virtual environment to be. is an important concept in VR. Presence is used to measure how much a person feels like they are now in the virtual environment, instead of in the physical one. One way to measure presence is by recording a person’s heart rate and other signs of stress. If you get too close to a cliff edge in real life, you will likely experience certain sensations: a faster heartbeat, sweaty palms, and more rapid breathing. Measuring these same symptoms of stress can be also done with people on a virtual cliff edge in a simulated environment. One of the many ways VR is used outside of gaming is actually for the treatment of specific phobias, such as (fear of heights). With the careful use of VR by mental health professionals, people who have an intense fear of heights (or other types of phobias) can be treated by a process called , in which they are able to slowly master their fear in a safe environment [2].

Virtual reality has the potential to allow us to experience things we would likely never encounter in real life. The virtual environment we created for our friend only included the sense of vision. Advanced VR technology, however, incorporates other senses as well. The more of our senses that are correctly incorporated into a VR environment, the more immersive, or true-to-life, it is. The more immersive the VR world is, the more present we feel and the more we lose track of the place where we actually reside.

Conclusion

There is a big difference between learning about something through reading or watching documentaries and actually getting to experience it. Often, we learn about subjects, such as astronomy through textbooks and videos. In the future, however, science class might just include field trips to VR environments, where we get to explore and feel what it might be like to walk around on a Martian dune. Ultimately, this technology “tricks” our brain, making us feel like we are somewhere else by mimicking the perceptual experiences we have in the real world, and convincing us that we are our games, or on the surface of a different planet. How will use this exciting technology?

Glossary

Immersion: ↑ How well virtual reality is able to mimic or simulate the real world as we know it.

Cybersickness: ↑ A feeling of disorientation and/or nausea that can result from the illusion of moving through virtual environments. These unpleasant sensations can also be caused by lagging (or delays) between what your vision expects and what the virtual world presents.

Sensation: ↑ The different ways our body has of bringing us information about the world around us (for example, vision, hearing, touch, and taste), and the act of sending that information to our brain to perceive.

Perception: ↑ The process of our brain interpreting our senses into experiences.

Binocular Vision: ↑ Our left and right eyes are in slightly different positions on our head, and our brain is able to merge these two perspectives together much like looking through binoculars.

Stereopsis: ↑ Seeing in stereo. How our brain combines visual information from our left and right eyes into one single image.

Accelerometer: ↑ A device that can tell whether (and in what direction) something is moving.

Presence: ↑ How convincing we perceive a virtual environment to be.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

स्रोत : kids.frontiersin.org

virtual reality (VR), the use of computer modeling and simulation that enables a person to interact with an artificial three-dimensional (3-D) visual or other sensory environment. VR applications immerse the user in a computer-generated environment that simulates reality through the use of

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virtual reality (VR), the use of computer modeling and simulation that enables a person to interact with an artificial three-dimensional (3-D) visual or other sensory environment. VR applications immerse the user in a computer-generated environment that simulates reality through the use of interactive devices, which send and receive information and are worn as goggles, headsets, gloves, or body suits. In a typical VR format, a user wearing a helmet with a stereoscopic screen views animated images of a simulated environment. The illusion of “being there” (telepresence) is effected by motion sensors that pick up the user’s movements and adjust the view on the screen accordingly, usually in real time (the instant the user’s movement takes place). Thus, a user can tour a simulated suite of rooms, experiencing changing viewpoints and perspectives that are convincingly related to his own head turnings and steps. Wearing data gloves equipped with force-feedback devices that provide the sensation of touch, the user can even pick up and manipulate objects that he sees in the virtual environment.

The term virtual reality was coined in 1987 by Jaron Lanier, whose research and engineering contributed a number of products to the nascent VR industry. A common thread linking early VR research and technology development in the United States was the role of the federal government, particularly the Department of Defense, the National Science Foundation, and the National Aeronautics and Space Administration (NASA). Projects funded by these agencies and pursued at university-based research laboratories yielded an extensive pool of talented personnel in fields such as computer graphics, simulation, and networked environments and established links between academic, military, and commercial work. The history of this technological development, and the social context in which it took place, is the subject of this article.

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Early work

Artists, performers, and entertainers have always been interested in techniques for creating imaginative worlds, setting narratives in fictional spaces, and deceiving the senses. Numerous precedents for the suspension of disbelief in an artificial world in artistic and entertainment media preceded virtual reality. Illusionary spaces created by paintings or views have been constructed for residences and public spaces since antiquity, culminating in the monumental panoramas of the 18th and 19th centuries. Panoramas blurred the visual boundaries between the two-dimensional images displaying the main scenes and the three-dimensional spaces from which these were viewed, creating an illusion of immersion in the events depicted. This image tradition stimulated the creation of a series of media—from futuristic theatre designs, stereopticons, and 3-D movies to IMAX movie theatres—over the course of the 20th century to achieve similar effects. For example, the Cinerama widescreen film format, originally called Vitarama when invented for the 1939 New York World’s Fair by Fred Waller and Ralph Walker, originated in Waller’s studies of vision and depth perception. Waller’s work led him to focus on the importance of peripheral vision for immersion in an artificial environment, and his goal was to devise a projection technology that could duplicate the entire human field of vision. The Vitarama process used multiple cameras and projectors and an arc-shaped screen to create the illusion of immersion in the space perceived by a viewer. Though Vitarama was not a commercial hit until the mid-1950s (as Cinerama), the Army Air Corps successfully used the system during World War II for anti-aircraft training under the name Waller Flexible Gunnery Trainer—an example of the link between entertainment technology and military simulation that would later advance the development of virtual reality.

Panorama of the Battle of Gettysburg, painting by Paul Philippoteaux, 1883; at Gettysburg National Military Park, Pennsylvania

James P. Rowan

Sensory stimulation was a promising method for creating virtual environments before the use of computers. After the release of a promotional film called This Is Cinerama (1952), the cinematographer Morton Heilig became fascinated with Cinerama and 3-D movies. Like Waller, he studied human sensory signals and illusions, hoping to realize a “cinema of the future.” By late 1960, Heilig had built an individual console with a variety of inputs—stereoscopic images, motion chair, audio, temperature changes, odours, and blown air—that he patented in 1962 as the Sensorama Simulator, designed to “stimulate the senses of an individual to simulate an actual experience realistically.” During the work on Sensorama, he also designed the Telesphere Mask, a head-mounted “stereoscopic 3-D TV display” that he patented in 1960. Although Heilig was unsuccessful in his efforts to market Sensorama, in the mid-1960s he extended the idea to a multiviewer theatre concept patented as the Experience Theater and a similar system called Thrillerama for the Walt Disney Company.

The seeds for virtual reality were planted in several computing fields during the 1950s and ’60s, especially in 3-D interactive computer graphics and vehicle/flight simulation. Beginning in the late 1940s, Project Whirlwind, funded by the U.S. Navy, and its successor project, the SAGE (Semi-Automated Ground Environment) early-warning radar system, funded by the U.S. Air Force, first utilized cathode-ray tube (CRT) displays and input devices such as light pens (originally called “light guns”). By the time the SAGE system became operational in 1957, air force operators were routinely using these devices to display aircraft positions and manipulate related data.

During the 1950s, the popular cultural image of the computer was that of a calculating machine, an automated electronic brain capable of manipulating data at previously unimaginable speeds. The advent of more affordable second-generation (transistor) and third-generation (integrated circuit) computers emancipated the machines from this narrow view, and in doing so it shifted attention to ways in which computing could augment human potential rather than simply substituting for it in specialized domains conducive to number crunching. In 1960 Joseph Licklider, a professor at the Massachusetts Institute of Technology (MIT) specializing in psychoacoustics, posited a “man-computer symbiosis” and applied psychological principles to human-computer interactions and interfaces. He argued that a partnership between computers and the human brain would surpass the capabilities of either alone. As founding director of the new Information Processing Techniques Office (IPTO) of the Defense Advanced Research Projects Agency (DARPA), Licklider was able to fund and encourage projects that aligned with his vision of human-computer interaction while also serving priorities for military systems, such as data visualization and command-and-control systems.

Another pioneer was electrical engineer and computer scientist Ivan Sutherland, who began his work in computer graphics at MIT’s Lincoln Laboratory (where Whirlwind and SAGE had been developed). In 1963 Sutherland completed Sketchpad, a system for drawing interactively on a CRT display with a light pen and control board. Sutherland paid careful attention to the structure of data representation, which made his system useful for the interactive manipulation of images. In 1964 he was put in charge of IPTO, and from 1968 to 1976 he led the computer graphics program at the University of Utah, one of DARPA’s premier research centres. In 1965 Sutherland outlined the characteristics of what he called the “ultimate display” and speculated on how computer imagery could construct plausible and richly articulated virtual worlds. His notion of such a world began with visual representation and sensory input, but it did not end there; he also called for multiple modes of sensory input. DARPA sponsored work during the 1960s on output and input devices aligned with this vision, such as the Sketchpad III system by Timothy Johnson, which presented 3-D views of objects; Larry Roberts’s Lincoln Wand, a system for drawing in three dimensions; and Douglas Engelbart’s invention of a new input device, the computer mouse.

Within a few years, Sutherland contributed the technological artifact most often identified with virtual reality, the head-mounted 3-D computer display. In 1967 Bell Helicopter (now part of Textron Inc.) carried out tests in which a helicopter pilot wore a head-mounted display (HMD) that showed video from a servo-controlled infrared camera mounted beneath the helicopter. The camera moved with the pilot’s head, both augmenting his night vision and providing a level of immersion sufficient for the pilot to equate his field of vision with the images from the camera. This kind of system would later be called “augmented reality” because it enhanced a human capacity (vision) in the real world. When Sutherland left DARPA for Harvard University in 1966, he began work on a tethered display for computer images (see photograph). This was an apparatus shaped to fit over the head, with goggles that displayed computer-generated graphical output. Because the display was too heavy to be borne comfortably, it was held in place by a suspension system. Two small CRT displays were mounted in the device, near the wearer’s ears, and mirrors reflected the images to his eyes, creating a stereo 3-D visual environment that could be viewed comfortably at a short distance. The HMD also tracked where the wearer was looking so that correct images would be generated for his field of vision. The viewer’s immersion in the displayed virtual space was intensified by the visual isolation of the HMD, yet other senses were not isolated to the same degree and the wearer could continue to walk around.

Early head-mounted display device developed by Ivan Sutherland at Harvard University, c. 1967.Courtesy of Ivan Sutherland

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