What is vr and what is its use?

The English full name of VR is Virtual Reality, and the Chinese name is Virtual Reality.

Virtual reality technology is a computer simulation system that can create and experience virtual worlds. It uses computer to generate a simulation environment, which is a multi-source information fusion, interactive three-dimensional dynamic scene and entity behavior system simulation, so that users are immersed in this environment.

1. Introduction

Virtual reality technology is an important direction of simulation technology, which integrates simulation technology, computer graphics, man-machine interface technology, multimedia technology, sensing technology, network technology and other technologies, and is a challenging cross-cutting technology frontier discipline and research field. Virtual reality technology mainly includes simulated environment, perception, natural skills and sensing equipment. The simulation environment is a computer-generated real-time dynamic three-dimensional realistic image. Perception means that the ideal VR should have the perception that everyone has. In addition to the visual perception produced by computer graphics technology, there are hearing, touch, force and movement, and even smell and taste, also known as multi-perception. Natural skills refer to people's head rotation, eyes, gestures or other human actions. The computer processes the data adapted to the actions of the participants, responds to the user's input in real time, and feeds it back to the user's five senses respectively. Sensing equipment refers to three-dimensional interactive equipment.

2. Development history

The development history of virtual reality technology can be roughly divided into four stages: the simulation of sound and shape dynamics is the first stage (before 1963); Virtual reality budded into the second stage (1963-1972); The emergence of the concept of virtual reality and the initial formation of its theory are the third stage (1973-1989); The further improvement and application of virtual reality theory is the fourth stage (1990 -2004).

3. Characteristics

Multi-sensory perception

In addition to the general computer visual perception, there are auditory perception, tactile perception, motion perception, and even taste, smell and perception. The ideal virtual reality should have the perceptual function that everyone has.

attend

Refers to the real degree of being the protagonist that users feel in the simulation environment. The ideal simulation environment should reach the point where it is difficult for users to distinguish between true and false.

interactivity

Refers to the user's operability of objects in the simulated environment and the naturalness of getting feedback from the environment.

independence

Refers to the degree to which objects in the virtual environment act according to the laws of physical motion in the real world.

4. Key technologies

show

When people look at the world around them, they get slightly different images because of different eye positions. These images are fused in their minds, forming a whole picture of the world around them, including the information of distance. Of course, distance information can also be obtained by other methods, such as the distance of eye focal length, the comparison of object size and so on.

Binocular stereo vision plays a very important role in virtual reality system. Different images seen by users' eyes are generated separately and displayed on different monitors. Some systems use a single monitor, but after the user wears special glasses, one eye can only see odd-numbered images, and the other eye can only see even-numbered images. The difference between odd-numbered frames and even-numbered frames, that is, parallax, produces a three-dimensional sense.

sound

People can judge the direction of sound source well. In the horizontal direction, we determine the direction of sound through the phase difference and intensity difference of sound, because the time or distance for sound to reach two ears is different. The common stereo effect is achieved by hearing different sounds recorded in different positions in the left and right ears, so there will be a sense of direction. In real life, when your head turns, the direction of the sound you hear will change. But at present, in VR system, the direction of sound has nothing to do with the movement of the user's head.

Sensory feedback

In the virtual reality system, users can see a virtual cup. You can try to grab it, but your hand doesn't really touch the cup, and it may pass through the "surface" of the virtual cup, which is impossible in real life. The common device to solve this problem is to install some vibration contacts on the inner layer of gloves to simulate touch.

speech sound

In VR system, voice input and output are also very important. This requires that the virtual environment can understand human language and interact with people in real time. It is quite difficult to recognize human voice by computer, because both voice signals and natural language signals have their "multilaterality" and complexity. For example, there is no obvious pause between words in continuous pronunciation, and the pronunciation of the same word and the same word is influenced by the words before and after. Not only do different people say the same word differently, but also the pronunciation of the same person is influenced by psychology, physiology and environment.

5 technology application

Medicine. The application of virtual reality in medicine has very important practical significance. In a virtual environment, a virtual human model can be established. With the help of trackball, HMD and sensory gloves, students can easily understand the internal organs of human body, which is much more effective than the existing way of using textbooks.

Entertainment. Rich sensory ability and 3D display environment make VR an ideal video game tool. In recent years, VR has developed most rapidly in the entertainment field because of its low requirement for realism.

Military space. Simulation training has always been an important topic in the military and aerospace industries, which provides a broad application prospect for VR. DARPA has been working on a virtual battlefield system named SIMNET since 1980s, aiming at providing coordinated tank training, which can connect more than 200 simulators. In addition, VR technology can also be used to simulate zero-gravity environment, instead of astronauts' irregular underwater training methods.

Interior design. Virtual reality is not only a demonstration medium, but also a design tool.

Real estate development. With the intensification of competition in the real estate industry, the traditional display means such as floor plan, performance chart, sand table and model house are far from meeting the needs of consumers.

Industrial simulation. Great changes have taken place in today's world industry, and large-scale sea tactics have long been unsuitable for the development of industry. The application of advanced science and technology shows great power, especially the application of virtual reality technology, which is carrying out an unprecedented revolution in industry. Virtual reality has been widely used in all aspects of industry by some large enterprises in the world, which has played an important role in improving development efficiency, strengthening data collection, analysis and processing capabilities, reducing decision-making mistakes and reducing enterprise risks.

Emergency deduction. Nip in the bud is the focus of all walks of life, especially some dangerous industries (fire protection, electric power, petroleum, minerals, etc.). How to ensure the minimum loss when an accident comes is a traditional and effective preventive method, but its disadvantages are also quite obvious and the input cost is high. Every deduction requires a lot of manpower and material resources, and a lot of investment makes it impossible to carry out it often. The emergence of virtual reality provides a brand-new development model for emergency drills, which simulates the accident scene into a virtual scene, artificially creates various accidents and organizes participants to make correct responses.

Games. Three-dimensional game is not only one of the important application directions of virtual reality technology, but also plays a huge demand traction role for the rapid development of virtual reality technology. Although there are many technical problems, in the highly competitive game market, virtual reality technology has been paid more and more attention and applied.

Web3D

Oculus Rift opens a new era of virtual reality games [3]

Web3D has four main application directions: business, education, entertainment and virtual community.

Roads and bridges. Urban planning has always been one of the most urgent fields of brand-new visualization technology. Virtual reality technology can be widely used in all aspects of urban planning and bring tangible and considerable benefits.

Geography. Using virtual reality technology, the three-dimensional ground model, orthophoto and three-dimensional model of urban streets, buildings and municipal facilities are fused together to reproduce the landscape of urban buildings and blocks. Users can intuitively see the vivid urban street landscape on the display screen, and can conduct a series of operations such as inquiry, measurement, roaming and flight browsing. So as to meet the needs of visualization development of digital city technology from two-dimensional GIS to three-dimensional virtual reality, and provide reference for urban planning, community service, property management, fire safety and so on.

Education. The application of virtual reality in education is a leap in the development of educational technology. It creates an "autonomous learning" environment, which replaces the traditional learning mode of "promoting learning through teaching" and becomes a new learning mode for learners to acquire knowledge and skills through their interaction with the information environment.

There are also studios, hydrogeology, technical training, shipbuilding, automobile simulation, rail transit, biomechanics, digital earth, virtual reality and other aspects will have great application value.

But from now on, there is still a long way to go before virtual reality technology really enters the consumer market, including Oculus. Oculus is also discussing the problems faced by virtual reality technology and constantly seeking solutions. Although all the questions will be answered in the end, it is unlikely that they will all be solved overnight.

At present, there are still great technical limitations in how developers can provide users with a truly immersive game or application experience, and some problems have not been well solved.