Virtual Reality

The Ultimate Guide to Virtual Reality Technology

Introduction to Virtual Reality (VR)

Virtual reality literally makes it possible to experience anything, anywhere, anytime. It is the most immersive type of reality technology and can convince the human brain that it is somewhere it is really not. Head mounted displays are used with headphones and hand controllers to provide a fully immersive experience. With the largest technology companies on planet earth (Facebook, Google, and Microsoft) currently investing billions of dollars into virtual reality companies and startups, the future of virtual reality is set to be a pillar of our everyday lives.

Virtual Reality Explained

Virtual Reality Definition What is Virtual Reality (VR)?

noun

A realistic three-dimensional image or artificial environment that is created with a mixture of interactive hardware and software, and presented to the user in such a way that the any doubts are suspended and it is accepted as a real environment in which it is interacted with in a seemingly real or physical way.


Virtual Reality Explained Simple Explanation of Virtual Reality (VR)

Virtual reality (also called Virtual Realities or VR) is best understood by first defining what it aims to achieve - total immersion. Total immersion means that the sensory experience feels so real, that we forget it is a virtual-artificial environment and begin to interact with it as we would naturally in the real world. In a virtual reality environment, a completely synthetic world may or may not mimic the properties of a real-world environment. This means that the virtual reality environment may simulate an everyday setting (e.g. walking around the streets of London), or may exceed the bounds of physical reality by creating a world in which the physical laws governing gravity, time and material properties no longer hold (e.g. shooting space aliens on a foreign gravityless planet).

Key Elements of a Virtual Reality Experience

  1. Virtual World
  2. A virtual world is a three-dimensional environment that is often, but not necessarily, realized through a medium (i.e. rendering, display, etc.) where one can interact with others and create objects as part of that interaction. In a virtual world, visual perspectives are responsive to changes in movement and interactions mimic those experienced in the real world.

  3. Immersion
  4. Virtual reality immersion is the perception of being physically present in a non-physical world. It encompasses the sense of presence, which is the point where the human brain believes that is somewhere it is really not, and is accomplished through purely mental and/or physical means. The state of total immersion exists when enough senses are activated to create the perception of being present in a non-physical world. Two common types of immersion include:
    • Mental Immersion - A deep mental state of engagement, with suspension of disbelief that one is in a virtual environment.
    • Physical Immersion - Exhibited physical engagement in a virtual environment, with suspension of disbelief that one is in a virtual environment.

  5. Sensory Feedback
  6. Virtual reality requires as many of our senses as possible to be simulated. These senses include vision (visual), hearing (aural), touch (haptic), and more. Properly stimulating these sense requires sensory feedback, which is achieved through integrated hardware and software (also known as inputs). Examples of this hardware and inputs are discussed below as key components to a virtual reality system , which include head mounted displays (HMD), special gloves or hand accessories, and hand controls.

  7. Interactivity
  8. The element of interaction is crucial for virtual reality experiences to provide users with enough comfort to naturally engage with the virtual environment. If the virtual environment responds to a user’s action in a natural manner, excitement and senses of immersion will remain. If the virtual environment cannot respond quick enough, the human brain will quickly notice and the sense of immersion will diminish. Virtual environment responses to interaction can include the way a participant moves around or changes in their viewpoint; generally through movements of their head.

Types of Virtual Reality Virtual Reality (VR) Categories

Several categories of virtual reality technologies exist, with more likely to emerge as this technology progresses. The various types of virtual reality differ in their levels of immersion and applicational use cases. Below, we explore a few of the virtual reality categories:

Non-Immersive


Non Immersive Virtual Reality

Non-immersive simulations are the least immersive implementation of virtual reality technology. In a non-immersive simulation, only a subset of the user's senses are stimulated, allowing for peripheral awareness of the reality outside the virtual reality simulation. Users enter into these three-dimensional virtual environments through a portal or window by utilising standard high resolution monitors powered by processing power typically found on conventional desktop workstations.

Semi-Immersive


Semi Immersive Virtual Reality

Semi-immersive simulations provide a more immersive experience, in which the user is partly but not fully immersed in a virtual environment. Semi-immersive simulations closely resemble and utilize many of the same technologies found in flight simulation. Semi-immersive simulations are powered by high performance graphical computing systems, which are often then coupled with large screen projector systems or multiple television projection systems to properly stimulate the user's visuals.

Fully-Immersive


Fully Immersive Virtual Reality

Fully-immersive simulations provide the most immersive implementation of virtual reality technology. In a fully-immersive simulation, hardware such as head-mounted displays and motion detecting devices are used to stimulate all of a user's senses. Fully immersive simulations are able to provide very realistic user experiences by delivering a wide field of view, high resolutions, increased update rates (also called refresh rate), and high levels of contrast into a user's head-mounted display (HMD).


How Does Virtual Reality Work? How Does VR work?

In order for the human brain to accept an artificial, virtual environment as real, it has to not only look real, but also feel real. Looking real can be achieved by wearing a head-mounted display (HMD) that displays a recreated life size, 3D virtual environment without the boundaries usually seen on TV or a computer screen. Feeling real can be achieved through handheld input devices such as motion trackers that base interactivity on the user’s movements. By stimulating many of the same senses one would use to navigate in the real world, virtual reality environments are feeling increasingly more like the natural world. Below, we explore some of the key components to behind this system.

Key Components in a Virtual Reality System

  1. PC (Personal Computer)/Console/Smartphone
  2. Virtual reality content, which is the what users view inside of a virtual reality headset, is equally important as the headset itself. In order to power these interactive three-dimensional environments, significant computing power is required. This is where PC (Personal Computer), consoles, and smartphones come in. They act as the engine to power the content being produced.
  3. Head-Mounted Display
  4. A head-mounted display (also called HMD, Headset, or Goggles) is a type of device that contains a display mounted in front of a user’s eyes. This display usually covers the user's full field of view and displays virtual reality content. Some virtual reality head mounted displays utilize smartphone displays, including the Google Cardboard or Samsung Gear VR. Head-mounted displays are often also accompanied with a headset to provide for audio stimulation.
  5. Input Devices
  6. Input devices are one of the two categories of components that provide users with a sense of immersion (i.e. convincing the human brain to accept an artificial environment as real). They provide users with a more natural way to navigate and interact within a virtual reality environment. Some of the more common forms of virtual reality input devices include:
    • Joysticks
    • Force Balls/Tracking Balls
    • Controller Wands
    • Data Gloves
    • Trackpads
    • On-Device Control Buttons
    • Motion Trackers/Bodysuits
    • Treadmills
    • Motion Platforms (Virtuix Omni)

How Virtual Reality Headsets Work (Inside)

Inside of each virtual reality head-mounted display (HMD) is a series of sensors, individual eye displays, lenses, and display screen(s), among other various components. The Ifixit Oculus Rift teardown offers an excellent step-by-step teardown and look inside of one of the most popular virtual reality headsets. Below we explore some of the key components inside of a virtual reality headset.

Key Components Inside of a Virtual Reality Headset

Sensors

The three most common sensors in a virtual reality headset are magnetometers, accelerometers and gyroscopes. These sensors work together by measuring the user’s motions and direction in space. Their ultimate goal is to achieve true six-degrees-of-freedom (6DoF), which covers all the degrees of motion for an object in space.

  1. Magnetometer - The magnetometer tells your device which direction it is facing on the surface of the earth. The magnetometer acts as a sort of compass for the device. As such, it is able to do this by measuring magnetic fields.
  2. Accelerometers - The accelerometer tells your device which way up it is. To do this, your device will have several accelerometers to work together measuring things like gravitational pull in relation the accelerometer measuring the device’s orientation.
  3. Gyroscopes - A gyroscope calculates the orientation of your device. It does this to either help your device maintain a particular orientation or make sure it properly changes orientation when it should.

Lenses

Lenses lie between your eyes and pixels on the display screen(s). They focus and reshape the picture for each eye by angling two 2D images to mimic how each of our eyes take in views of the world (also called stereoscopic). This creates an impression of depth and solidity, which we perceive to be a three-dimensional image. Lenses on each virtual reality device are not one-size-fits all and have to be adjusted for initial use as all devices have different lens properties.

Display Screens

Display screens show the images that user view through the lenses. They are typically LCD and receive video feed from the computer or smartphone. Depending on the headset, the video feed is either sent to one display or two displays (one per eye). This happens via wireless connection, smartphone connection, or HDMI. The most common types of virtual reality display technology is a Liquid Crystal Display (LCD) screen, similar to the kinds used in smartphones and computer monitors. An alternative display technology is an Organic Light-Emitting Diode (OLED) screen.

Processing

Virtual reality systems demand a substantial amount of power, even in comparison to notoriously power hungry gaming systems. The processing power required by virtual reality systems can be broken down into several categories:

  1. Input Processor – Controls the devices used to input information to the computer. They retrieve and distribute data to the rest of the system with minimal lag time. Examples include keyboards, mouses, 3D position trackers, and voice recognition systems.
  2. Simulation Processor – Takes the user inputs along with any other tasks that are programmed from the natural world and determines the actions that will take place in the virtual world. This is a core component of the VR system.
  3. Rendering Processor – Creates the sensations that are output to the user. These include visual, auditory, haptic and other sensory systems. Separate rendering processes are used for each sensory system.

Other Concepts to Understand How Virtual Reality Headsets Work

Field of View

Field of view (also called Field of Vision or FOV) is an important component used in virtual reality to provide users with a realistic perception of their environmental landscape. Simply put, field of view refers to how wide the picture is. Field of view is measured based on the degree of display (e.g. 360°). Most high-end headsets make do with 100° or 110° field of view which is sufficient for most virtual reality content.

Frame Rate

Frame rate refers to the frequency (rate) at which the display screen shows consecutive images, which are also called frames. Television shows run at 30 frames per second (fps) and some game consoles run at 60 frames per second (fps). In virtual reality, a minimum frame rate of approximately 60 frames per second is needed to avoid content stuttering or cause of simulation sickness. The Oculus Rift runs at 90 fps, providing Oculus Rift users with a very lifelike experience. Future Frame rates for virtual reality headsets are set to inevitably continue getting faster, providing for a more realistic experience.

Latency

Latency refers to the amount of time it takes for an image displayed in a user’s headset to catch up to their changing head position. Latency can also the thought of as a delay, and is measured in milliseconds (ms). In order for an experience to feel real, latency usually needs to be in the range of 20 milliseconds (ms) or less. Low latency, or very little delay, is needed to make the human brain accept the virtual environment as real. The lower the latency, the better. The higher the latency, a noticeable and unnatural lag may set in, consequently causing simulation sickness for the user.

Audio

Virtual reality audio may not be as technically-complex as the visual components, however, it is an equally important component to stimulate a user’s senses and achieve immersion. Most virtual reality headsets provide users with the option to use their own headphones in conjunction with a headset. Other headsets may include their own integrated headphones. Virtual reality audio works via positional, multi-speaker audio (often called Positional Audio) that gives the illusion of a 3-dimensional world. Positional audio is a way of seeing with your ears and is used in virtual reality because it can provide cues to gain a user’s attention, or give them information that may not be presented visually. This technology is already quite common and often found in home theater surround sound systems.

Tracking

Tracking handles the vital task of understanding a user’s movements and then acting upon them accordingly to maintain full immersion in virtual reality. Below, we explore the three of the main types of virtual reality tracking:


Head Tracking

Virtual Reality Head Tracking
Head tracking refers to the way in which the view in front of you will shift as you look up, down and side-to-side. A system called six degrees of freedom (6DoF) plots your head in terms of your x, y and z axis to measure head movements forward and backwards, side-to-side and shoulder to shoulder, otherwise known as pitch, yaw and roll. Head tracking utilizes a series of sensors, vital to any virtual reality headset, which includes a gyroscope, accelerometer, and magnetometer. Head-tracking technology must be low latency in order to be effective. Anything above 50ms will cause a lag between the headset movement and virtual reality environment changes.

Motion Tracking

Virtual Reality Motion Tracking
Motion tracking is the way in which you view and interact with your own body (e.g. hands, movements, etc). One of the most natural motion-related acts is to want to be able to see your own hands (virtually) in front of you. To do this, virtual reality input accessories such as gloves can be used. Other motion tracking devices such as wireless controllers, joysticks, treadmills, and motion platforms are now being used to supplement the headset and provide an even more immersive experience. Many of these input accessories utilize sensors to detect gestures such as pointing and waving. Virtual reality systems such as HTC’s Vive headset, utilize base stations to track the sensors from the headset and controllers.

Eye Tracking

Virtual Reality Eye Tracking
Eye tracking technology is still maturing, however, it may be one of the most important missing pieces to complete the virtual reality full immersion puzzle. Eye tracking involves tracking the human eyes via an infrared sensor that monitors your eye movement inside the headset. The main advantage to this type of tracking is that depth of field (i.e. distance) becomes much more realistic. In a virtual reality headset, the objects that our eyes focus on, need to look as life-like as possible. Without eye tracking, everything remains in focus as you move your eyes - but not your head - around a scene, thus causing a greater likeliness of simulation sickness.

Virtual Reality Use Case Example: Aviation Training

A well established example of virtual reality already in use is in the field of aviation training. From flying a commercial airplane out of a crowded international airport, to training for a dangerous night-flight using only night vision, virtual reality can provide significant benefits to aspiring pilots.

Commercial

Piloting commercial flights require taking on tremendous responsibility, as there are often several hundred passengers on any given flight. Training for this responsibility requires both conceptual and hands on training. The initial hands on training can often be supplemented by use of a simulator. These simulators, which employ sophisticated computer models, use virtual reality to recreate what a pilot should expect when they actually flying. Simulators even use hydraulics to recreate the feeling of takeoff and landing. The benefit to using a virtual reality flight simulator is that this all takes place in a controlled environment, which is forgiving to mistakes and pose virtually no risk.

Military

Almost every flight by an active military pilot can be a life threatening mission. Training to become a military pilot requires unique skillsets and knowledge of how to react in uncertain situations. Almost all branches of them military, including the Air Force, Army, and Navy, now use virtual reality technologies to train pilots. By using virtual reality, soldiers are taught how to fly in battle, how to handle emergencies and recover fast, and how to coordinate air support with ground operations. Since simulators often have visual acuity over the entire 360-degree field of view, these simulators provide trainees with very deep levels of immersion. As mentioned above, the benefit to using a virtual reality flight simulator is that this all takes place in a controlled environment, which is forgiving to mistakes and poses virtually no risk.