Virtual Reality (VR)
Virtual reality technologies have appeared recently, and the terminology has not yet settled down (this is discussed in detail in the article “Augmented, virtual and other realities”). Wikipedia gives the following definitions.
Virtual reality (VR, virtual reality, VR, artificial reality) is a world created by technical means, transmitted to a person through his sensations: vision, hearing, touch and others. Virtual reality simulates both exposure and responses to exposure. To create a convincing complex of sensations of reality, computer synthesis of properties and reactions of virtual reality is performed in real time.
Virtual reality should not be confused with augmented reality. Their fundamental difference is that the virtual constructs a new artificial world, while augmented reality only introduces individual artificial elements into the perception of the real world.
Virtual reality systems are devices that more fully, in comparison with conventional computer systems, simulate interaction with a virtual environment by influencing all five human senses.
Such systems do not yet exist in full, but when creating virtual reality, developers are trying to achieve that it was:
• believable – kept the user feeling the reality of what was happening
• interactive – provided interaction with the environment
• accessible for study – provided the opportunity to explore a large, detailed world
• creating the effect of presence – involved in the process both the brain and the body of the user, affecting the maximum possible number of sensory organs
Obviously, achieving these goals is only possible with the use of high-performance hardware and software.
Types of virtual reality
At this stage in the development of VR technologies, the following types can be distinguished among them.
Fully immersive VR technology for lifelike virtual reality simulations with high levels of detail. To implement them, you need a high-performance computer that can recognize and respond to user actions in real time, and special equipment that provides an immersive effect.
VR technology without immersion. These include simulations with images, sound and controllers that are broadcast on a screen, preferably a widescreen one. Such systems are referred to as virtual reality, since in terms of the degree of impact on the viewer, they are much superior to other multimedia means, although they do not fully implement the requirements for VR.
VR technologies with shared infrastructure. These include Second Life – a three-dimensional virtual world with elements of a social network, which has over a million active users, the game Minecraft and others. Such worlds do not provide full immersion (however, Minecraft already has a version for virtual reality, which supports the Oculus Rift and Gear VR helmets). But on the other hand, in virtual worlds, interaction with other users is well organized, which is often lacking in “real” virtual reality products.
Virtual worlds are used not only in the gaming industry: with platforms such as 3D Immersive Collaboration, it is possible to organize 3D work and learning spaces – this is called “immersive collaboration”. Providing full immersion and, at the same time, user interaction in virtuality is one of the important directions of VR development.
VR based on internet technologies. These include, first of all, the Virtual Reality Markup Language, similar to HTML. Now this technology is considered outdated, but it is possible that in the future virtual reality will also be created using Internet technologies.1,2
How VR technology works
The most common means of immersion in virtual reality are specialized helmets / glasses. The display in front of the user’s eyes displays video in 3D. Attached to the body, a gyroscope and accelerometer track head movements and transmit data to a computing system, which changes the image on the display depending on the readings of the sensors. As a result, the user has the opportunity to “look around” inside virtual reality and feel like in the real world.
For a more realistic immersion in the world of virtual reality, in addition to sensors that track the position of the head, VR devices can use tracking systems that track the movements of the pupils of the eyes and allow you to determine where a person is looking at each moment, as well as track human body movements in order to repeat them in virtual the world. Such tracking can be carried out using special sensors or a video camera.
Traditional 2D controllers (mouse, joystick, etc.) are no longer enough to interact with virtual reality, so they are replaced with 3D controllers (manipulators that allow you to work in three-dimensional space).
Feedback devices are designed so that the user can even more fully experience everything that happens in the virtual world. Vibrating joysticks, swivel chairs, etc. can be used as such devices.3
VR devices and components
It is believed that 80% of information a person receives through sight. Therefore, the developers of VR systems pay great attention to the devices that provide imaging. As a rule, they are supplemented with stereo sound devices; work is underway on tactile influences and even imitation of smells. No effect on taste buds has been reported yet.
Virtual reality helmet
Modern virtual reality helmets (HMD-display, head-mounted display, video helmet) contain one or more displays that display images for the left and right eyes, a lens system for adjusting the image geometry, and a tracking system that tracks the orientation of the device in space. In appearance, they now look like glasses, so they are increasingly called VR headsets (VR headsets) or simply virtual reality glasses. They can be divided into three groups:
Glasses in which the image processing and output is provided by a smartphone (Android, iPhone, Windows Phone). A modern smartphone is a high-performance device capable of independently processing 3D images. Smartphone displays have a fairly high resolution. Almost every smartphone is equipped with sensors that allow you to determine the position of the device in space.
Glasses in which the image processing is provided by an external device (PC, Xbox, PlayStation, etc.). The external device must be high-performance, and the glasses must be equipped with position sensors.
Autonomous virtual reality glasses (Lenovo Mirage Solo, in collaboration with Google, Oculus Quest from Facebook, Samsung Gear VR, etc.) 4
Helmets are the main component of fully immersive VR, as they not only provide 3D imaging and stereo sound, but also partially isolate the user from the surrounding reality.
Such displays use the human mechanism of volume perception – motion parallax. For this, at each moment of time for the viewer, based on his position relative to the screen, a corresponding projection of a three-dimensional object is generated. Moving around the scene, the user can inspect it from all sides, while all objects in the scene will move relative to each other.
The phenomenon of parallax greatly enhances the perception of volume. Unlike 3D cinematography and 3D TV, which only use binocular vision, MotionParallax3D technology allows the user to view a 3D scene from all angles, as if all its objects were real. The displacement of the viewer relative to the screen, which violates the effect of volume in 3D cinema, in the MotionParallax3D system only enhances the effect.
A system using a parallax mechanism must capture the smallest movements of the user’s head and track them with high speed and accuracy so that the brain does not capture the distortion of the geometry of objects caused by the delay in image changes.5 The delay should be no more than 20 ms, for interactive games – no more than 11 ms 6
These devices usually provide incomplete immersion, as they are reproduced on displays and do not isolate the user from the environment. An exception is virtual reality rooms (CAVE, cave automatic virtual environment). In such rooms, a stereoscopic image is projected onto each wall, calculated for a specific point where the user is located. As a result, such an image surrounds a person from all sides, immerses him in himself. Some experts believe 7 that VR rooms are much better than VR helmets: they provide higher resolution, there is no need to wear a bulky device over the head, in which some even get seasick, and self-identification is easier due to the fact that the user can see himself at all times.
The multichannel speaker system allows localization of the sound source, so that the user can navigate the virtual world using hearing.