Abstract: Virtual Reality technology, English Virtual Reality, referred to as VR. It is an ideal man-machine communication technology. The three essential characteristics of this technology are immersion, interactivity and imagination. Since the invention of photorealistic panoramic simulator in 1962, this technology has attracted more and more attention from the public, and the products made by combining with other related technologies have more and more beneficial effects on human beings. This paper introduces the concept, status quo and practical application of virtual reality technology.

Keywords: virtual reality technology, man-machine communication, technical characteristics

1 the concept of virtual reality technology

The most essential characteristics of virtual reality technology can be summarized by three I, namely, Immersion, Interaction and Imagination. Immersion is the degree to which the user feels real in the virtual world. Interactivity refers to the degree to which users can manipulate objects in the virtual world and the real degree to which users can get feedback from the virtual world. Virtual reality technology as a new man-machine communication technology, different from the traditional mode of keyboard and mouse, using digital helmet, digital gloves and other complex sensor equipment, three-dimensional interaction technology, voice recognition, voice input technology has become an important means of human-machine interaction.

1.1 Research status at home and abroad

As the birthplace of VR technology, the research level of The United States basically represents the development level of VR technology in the world. At present, the basic research in this field in the United States mainly focuses on perception, user interface, background software and hardware. Its technical research into VR mainly includes aerospace, medical, education, design, entertainment and manufacturing. As a leading VR technology country in Europe, The UK has made important contributions to THE development of VR, especially in distributed parallel processing, auxiliary device design and application research. Japan is mainly committed to the establishment of large-scale VR knowledge base research, virtual reality in the game research is also leading. China's VR technology research started late, and there is still a certain gap with foreign developed countries, but now it has aroused the attention of relevant departments and scientists, and according to China's national conditions, the development of VR technology research plan. The ninth Five-Year Plan, the National Natural Science Foundation of China, and the National High Technology Research and Development Plan have all included VR in the research projects. Some key universities in China have been actively involved in this field.

The system composition of virtual reality technology

Virtual reality system consists of software and hardware. By integrating other technologies, a THREE-DIMENSIONAL virtual environment can be built, which is the basis of virtual reality technology to improve user immersion and sense of interaction.

2.1 Hardware composition of virtual reality technology

A complete virtual reality system consists of a virtual environment, with high performance computer as the core processor, virtual environment with head-mounted displays as the core of the visual system, in speech recognition, voice synthesis and positioning as the core of auditory system, Israel a tracker, data gloves and clothing as the main body position attitude tracking equipment, as well as taste, smell, touch and force feedback System and other functional units. Simply put, virtual reality technology is to create a virtual environment by means of computer simulation. The user is "placed" in the generated virtual environment through various sensing devices as input devices, and then the image is output through the output device. The technology of direct natural interaction between human and virtual environment, in this case the virtual environment is a three-dimensional image generated by computer. Natural interaction means that people operate objects in the environment in a daily way and can get real-time stereoscopic feedback.

2.2 Software composition of virtual reality technology

2.2.1 database

The core of virtual reality technology is to build a THREE-DIMENSIONAL virtual environment, and the premise of building it is to use modeling technology to build a virtual object model, the object geometry, surface attributes, and dynamic attributes of data into the database. The role of the database is mainly to store all kinds of data needed in the virtual reality system. For all objects in the virtual reality system, the database needs to have corresponding models.

2.2.2 Application software

In order to realize virtual reality system, it needs a lot of auxiliary software support. These auxiliary software are generally used to prepare the materials needed to build virtual worlds. For example, 2d software like AutoCAD and Photoshop and architectural drawing software need to be used in early data collection and image arrangement. When modeling texture, mainstream 3D software such as 3DMax and MAYA should be used. In preparing audio and video materials, need to use Audition, Premiere and other software. In order to organize all kinds of media materials together and form a complete virtual world with interactive functions, professional virtual reality engine software is needed, which is mainly responsible for model assembly, hot spot control, motion mode setting, sound generation and other work in the virtual reality system. In addition, it establishes the necessary interfaces between the virtual world and the backend database, and between the virtual world and the interactive hardware.

3. Important technology of virtual reality technology

The realization of virtual reality requires the synthesis of a variety of technologies to construct a real and credible virtual environment. With the help of necessary external devices, users can interact with things in the virtual environment naturally, just as they are on the scene. Key technologies are as follows:

3.1 Dynamic environment modeling technology

The purpose of this technique is to obtain the 3d data of the actual environment, and establish the corresponding 3D environment model by using the obtained 3D data according to the needs of application. The core of virtual reality technology is to construct virtual THREE-DIMENSIONAL environment, which not only requires approaching reality but also emphasizes interactivity. This will improve the user's sense of immersion and interaction.

3.2 Stereoscopic display and sensor technology

The interactive capability of virtual reality depends on the development of stereoscopic display and sensor technology. The existing virtual reality is far from meeting the needs of the system. For example, in terms of hardware, data gloves have disadvantages such as large delay, low resolution, small scope of action and inconvenient use. The tracking accuracy and tracking range of virtual reality equipment also need to be improved, so it is necessary to develop a new 3D display technology.

3.3 Real-time 3D image generation technology

At present, the technology has been mature, the key is how to realize "real time" generation. For real-time purposes, ensure that the graphics refresh rate is at least 15 frames per second, and preferably higher than 30 frames per second. How to improve the refresh frequency without reducing the quality and complexity of graphics will be the research content of this technology.

3.4 System integration technology

Integration technology includes information synchronization technology, model calibration technology, data conversion technology, data management model, recognition and synthesis technology and so on. Because virtual reality includes a lot of perceptual information and models, system integration technology plays an important role.

3.5 Interaction Technology

In the virtual reality system, to realize the natural interaction between the user and the virtual world, special input and output devices must be used to identify the user's various information inputs and generate realistic feedback information in real time. Commonly used interactive technologies include: motion capture, tactile feedback, eye tracking, emG simulation, gesture tracking, direction tracking, voice interaction, etc.

4. Application of virtual reality technology

With the rapid and vigorous development of VR industry, the innovation ability of enterprises is also constantly improving, and the application range of relevant equipment is very wide. In recent years, VR virtual reality technology has been widely used in education, medicine, film and television entertainment, driving training and many other industries.

4.1 Education

VR technology has become a new educational way to promote the development of education. The traditional education is blindly to students with "knowledge", and now using the VR technology can be implemented to help students build vivid, real learning environment, let the student through the true feelings to enhance memory, compared with the passive knowledge, using the VR technology for autonomous learning can make students more easy to accept, but also can make the students to stimulate interest in learning.

4.2 Medical Field

Medical scientists use computers to simulate human tissues and organs in the virtual space, so that students can operate in the simulation, but also can let students feel the scalpel cut into human muscle tissue and touch bone feeling, can improve students' self-operation ability can also quickly master the key points of surgery. Surgeons can not only build a virtual model of the patient's body before surgery, but also perform a surgical rehearsal in the virtual space, which can greatly improve the success rate of surgery and allow more patients to recover.

4.3 Film and Television Entertainment

In recent years, due to the wide application of VR technology in the film and television industry, the first on-site 9DVR experience museum based on VR technology has been realized. 9DVR Experience Hall has exerted a great influence on the film and television entertainment market since it was built. 9DVR Experience Hall allows viewers to experience themselves in real scenes and immerse themselves in the virtual environment created by films.

4.4 Driving Training

On October 9, 2016, a new application of VR technology -- VR virtual driving technology appeared in the World Simulation Technology Application Exhibition. The technology is currently used in the field of driver training. On the application of VR in cutting-edge technologies in driving simulator, not only to implement the standardization of driving training, to ensure the driving training level, and developed a simulation road driving, by simulating the actual road conditions, allow students to apply the theoretical knowledge immediately in real scenarios to roads, avoid took a driver's license also dare not on the road, the road can't drive the embarrassing situation.

5 conclusion

Just like other emerging science and technology, virtual reality technology is the product of many related disciplines. We must clearly recognize that although the technical potential of this field is huge and the application prospect is very broad, there are still many unsolved theoretical problems and technical guarantees that have not been overcome. Nevertheless, its unique advantages provide a new breakthrough for the development of various fields. At the same time, I believe that with the rapid development of network technology, virtual reality technology will get more rapid development, will be widely used in human daily life, to bring a new look to people's life.

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