the English full name of VR is Virtual Reality, and the Chinese translation is virtual reality.
Virtual reality technology is a computer simulation system that can create and experience a virtual world. It uses computers to generate a simulation environment, which is a multi-source information fusion, interactive three-dimensional dynamic scene and entity behavior system simulation to immerse users in this environment.
1. Introduction
Virtual reality technology is an important direction of simulation technology, a collection of simulation technology, computer graphics, man-machine interface technology, multimedia technology, sensing technology, network technology and other technologies, and it is a challenging cross-cutting technology frontier discipline and research field. Virtual reality technology (VR) mainly includes simulated environment, perception, natural skills and sensing equipment. The simulation environment is a computer generated, real-time and dynamic three-dimensional realistic image. Perception means that the ideal VR should have the perception that all people have. In addition to the visual perception generated by computer graphics technology, there are also senses of hearing, touch, force and movement, and even sense of smell and taste, which is also called multi-perception. Natural skills refer to people's head rotation, eyes, gestures, or other human actions. The computer processes the data adapted to the participants' actions, responds to the users' input in real time, and feeds it back to the users' 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) containing virtual reality thought; Virtual reality sprouted 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 (199 -24).
3. Features
Multi-perception
refers to hearing perception, tactile perception, motion perception, and even taste, smell, perception, etc. The ideal virtual reality should have the perceptual function that all people have.
presence
refers to the real degree to which users feel that they exist as protagonists in the simulation environment. The ideal simulation environment should reach a level that makes it 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.
autonomy
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
Display
When people look at the world around them, the images they get are slightly different because of the different positions of their eyes. These images are fused in their minds to form an overall picture of the world around them, which includes information about the 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.
in VR system, binocular stereo vision plays a great role. 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 and even frames, that is, parallax, creates a stereoscopic impression.
sound
people can judge the direction of the sound source well. In the horizontal direction, we determine the direction of sound by 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 the left and right ears hearing different sounds recorded in different positions, so there will be a sense of direction. In real life, when the 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 a VR system, users can see a virtual cup. You can try to catch 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 vibrating contacts on the inner layer of gloves to simulate touch.
voice
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 for a computer to recognize human speech, because speech 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 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 VR in medicine has very important practical significance. In the 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 the 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. Because the requirements for the realism of VR in entertainment are not too high, VR has developed most rapidly in this field in recent years.
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, the Advanced Research Projects Agency (DARPA) of the US Department of Defense, has been working on a virtual battlefield system called SIMNET since 198s, in order to provide coordinated tank training, which can connect more than 2 simulators. In addition, VR technology can be used to simulate the zero-gravity environment and replace the non-standard underwater training method for astronauts.
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, traditional display means such as floor plan, performance chart, sand table and model house have been far from meeting the needs of consumers.
industrial simulation. Nowadays, great changes have taken place in the world industry, and the large-scale sea of people tactics have long since failed to adapt to the development of industry. The application of advanced science and technology has shown great power, especially the application of virtual reality technology, which is carrying out an unprecedented revolution on industry. Virtual reality has been widely used in all aspects of industry by some large enterprises in the world, which plays 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 attention in all walks of life, especially in certain dangerous industries (fire fighting, electric power, petroleum, minerals, etc.). How to ensure the minimum loss when an accident comes is a traditional and effective way to nip in the bud, 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 frequently. The emergence of virtual reality provides a brand-new development mode for emergency drills, which simulates the accident scene into a virtual scene, where various accidents are artificially created and the participants are organized 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, virtual reality technology has been paid more and more attention and applied in the highly competitive game market.
Web3D
Oculus Rift opens up 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 for brand-new visualization technology. Virtual reality technology can be widely used in all aspects of urban planning and bring tangible and considerable benefits.
geography. By using virtual reality technology, the three-dimensional ground model, orthophoto and three-dimensional models of urban streets, buildings and municipal facilities are fused together to reproduce the landscape of urban buildings and blocks. Users can visually see the vivid and realistic urban street landscape on the display screen, and can perform a series of operations such as inquiry, measurement, roaming, flight browsing, etc., so as to meet the visual development needs 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 environment of "autonomous learning", which is replaced by the traditional learning mode of "teaching to promote learning" as a new learning mode in which learners acquire knowledge and skills through the interaction between themselves and the information environment.
There are also studios, hydrogeology, technical training, shipbuilding, automobile simulation, rail transit, biomechanics, digital earth, virtual reality and other aspects that will have great application value.
But from now on, there is still a long way to go for virtual reality technology to really enter the consumer market, including Oculus. Inside Oculus, the problems faced by virtual reality technology are also discussed, and solutions are constantly being sought. Although all the questions will eventually be answered, it is unlikely that they will all be solved overnight.
At present, there are still some technical limitations in how developers can provide users with a truly immersive game or application experience, and some problems are still not well solved.