In 2016, aiming at the next generation of intelligent computing platform, an unprecedented wave of virtual reality technology emerged at home and abroad. Virtual reality is likely to become the next generation of personal computing and communications platform after the smartphone. Virtual reality is a new computer technology evolved from computer vision, simulation technology, human-computer interaction and other information technologies. By separating the visual from the real world, with the help of display devices, people can pass through and immerse in a completely virtual world. As a link between the digital world and the real scene, virtual reality and augmented reality have become one of the core technologies of immersive digital applications. With the support of related devices, immersive digital applications are bound to show explosive growth.

Classification of virtual reality technology

At present, VR technologies are mainly divided into four types: desktop, distributed, immersive and enhanced, as shown in Table 1 [1] :

Table 1: Technical classification of VR

Recently, consumer-grade VR devices include input and output, which can be divided into the following three types according to the output [2]:

1) Lightweight VR (e.g., mobile phone box). In other words, head-mounted VR, which relies on mobile devices, has no independent computing, storage accessories or display devices, so its immersion effect is poor, but its cost is low and it is easy to carry. The representative product is Gear VR with Controller launched by Samsung in cooperation with Oculus.

Figure 1: Gear VR launched by Samsung and Oculus in partnership

2) PC-based VR (or VR headset). It USES PC as the computing and storage platform. VR headset is wired to PC platform. It has a complex structure, but it has an independent display screen, so it has a good sense of immersion. The three most representative products are Oculus Rift S headset (Figure 2) [4], HTC Vive headset (Figure 3) [5] and PlayStation VR headset (Figure 4) [6].

Figure 2: Oculus Rift S headset

Figure 4: PlayStation VR

3) Stand-alone VR (or all-in-one machine). Built-in CPU/GPU, display screen and other components, can run independently. So far has not matured, but is expected to become the future of the mainstream device form. At present, the input devices mainly include motion capture device, position tracker, eye tracker, etc. In addition to the foreign Oculus, HTC and SONY, some of its representative products also have a commendable performance, such as Pico neo 2 (Figure 5) [7], iQIYI's adventures 2 Pro, NOLO X1 VR and other 6-dof VR all-in-one machines.

Figure 5: Pico Neo 2, Head-hand 6DoF VR All-in-one machine

Typical applications of VR

Typical VR application scenarios can be divided into consumer-oriented VR applications and producer-oriented VR applications according to their different groups.

VR applications for consumers

The game is VR

Games are an important breakthrough in VR technology, as well as a good way to know and learn new things in the easiest way. At present, the immersive game mode based on head-mounted device (HMD) has set off an upsurge in the industry. A number of companies have released virtual reality games and related devices that fundamentally change the traditional keyboard/gamepad mode. Among them, THE achievements of HTC VIVE in music playing games are highly attractive [8], as shown in Figure 6:

Figure 6: If You Want to Escape with Me LIV demo

HMD's real-time tracking can make up for the lack of 3D game immersion by adjusting the user's game perspective and improving the game experience mode. Although most games are still in the exploratory stage, VR/AR games are bound to be favored and pursued by a large number of young people as time goes by.

The film and television class VR

In terms of film and television entertainment, the application scene of VR technology has gone through multiple processes such as local video transformation, VR animation display, and production of UGC film and television through splicing algorithm with the help of 360° panoramic camera, binocular camera and other devices. In the film field, more films shot with VR technology enter the public's vision.

Digital Technology Museum/museum

In terms of digital science and technology museum/museum, it initially changed from participants browsing prefabricated virtual scene exhibits through keyboard and mouse operation to human-computer interaction with wearable devices such as 3D glasses, so as to better experience the "immersive" feeling. Some scholars believe that, based on 3D VR, the simple mode of displaying and describing objects is less conducive to the learning and understanding of cultural content than the narrative mode of traditional websites. In the end, however, the establishment of a cloud 3D virtual exhibition hall and the creation of a cultural heritage learning environment by means of virtual characters and games have won the affirmation of experts. While enhancing the interactivity, it also achieves the purpose of spreading knowledge.

At present, a series of large virtual museums have been established at home and abroad, such as Agamemnon Museum, The British Museum, Olympic Museum and so on. The appearance of these venues has successfully solved the limitations of time, space and interaction in physical museums, effectively shortened the renewal cycle of exhibits, and become an important popular science way to test new technologies and promote international exchanges and academic research.

VR applications for producers

Scientific calculation: Visualization of engineering simulation results

Siemens' STAR-CCM+ is a complete multi-physical field solution utilizing the Computational Continuum Mechanics Algorithms which not only performs fluid analysis but also analyzes structural stress/electromagnetic fields. Its goal is to have the ability to analyze any continuous physical field. Starting from the V13.02 version, its built-in Simcenter Star-CCM + Virtual Reality function enables users to observe the simulation results based on mechanics and thermodynamics in an immersive way, so as to better understand the physical meaning, deepen scientific insight and accelerate the product development process. For example, for turbine blades with internal cooling channels, we can check the mesh generation from the first perspective to predict whether the mesh quality is sufficient to produce correct numerical simulation results (see Figure 7).

Figure 7: Simcenter star-CCM + Virtual Reality, viewing the internal situation of the grid and structure from the first perspective

We can 3D print parts, but we can't look at mechanical parts. With VR, engineering software can perform "shuttle browsing," which allows us to quickly understand the complexity of these internal channels, all in about a minute or two. While using traditional mouse can also breaking the old cow pull to deal with the work, but the virtual reality technology to plug in the wings, scientific computing visualization results allows us to "percussion horseshoe disease, a day to see changan flower" - which is more help to capture the fleeting inspiration of science, found that the underlying problems in the design of - a belief that every scientific research workers have this experience.

Military psychological training

VR technology has the characteristics of immersion, Presence and interaction. Immersion, also known as Sensorimotor Immersion, refers to the degree of physical stimulation acting on the sensory system, and motor system's sensitivity to input stimuli. The sense of immersion is related to the neural pathway of sensorimotor in the virtual environment, the true degree of sensory stimulation and the reactivity of motor stimulus input (such as the movement of the head and body) [9]. The immersive feeling of VR technology can intervene in human psychology through human psychological behavior mechanism [10], psychophysiological mechanism [11, 12], cognitive neural mechanism [13, 14], etc. These are also the scientific basis of military psychological training in VIRTUAL reality.

Therefore, IN the field of military psychology, VR technology is widely used in psychological selection, psychological training and psychological therapy [15]. With its unique advantages, this technology will play an increasingly important role in future wars. "The Annual Development Report of World Defense Science and Technology (2017) points out that," Virtual training has become an important means of military technology training, which will accelerate its march to the battlefield and become the main driving force for the realization of national strategy.

For VR technology by constructing a virtual environment to trigger people's physiological and psychological reaction [9], can simulate the military situation in the high risk, high pressure and irreversible battlefield situation, largely at the same time to ensure the safety of military personnel, military mental training can make the implementation step by step higher, conditions, and controllable, repeatable operation, so the VR technology has been widely used in military training. The US military has extensively carried out psychological training systems based on VR technology, such as the "VRCPAT" training system [16], stress inoculation/management training [17 -- 19], mental resilience "Strain" training system [20 -- 22], and post-traumatic growth "BRAVEMIND" training system [23].

The application of OUR ARMY VR technology in the field of psychological training is still in the stage of theoretical construction [24]. In the acquisition of the chairman of military training and requirements of the combat, based on VR technology platform, needs to be set up in our army military requirements and operational style of VR stimulus library, establish a multi-dimensional evaluation system, explore the military psychological training mechanism, establishing the VR platform military training demonstration and promotion, through psychological training a strong army soldiers psychological quality, thus to enhance the combat effectiveness under the condition of our army generation has become an important issue to be solved.

conclusion

In the past few years, VR has made breakthrough achievements in theoretical research, key technology innovation, application expansion and other aspects. In the future, with the continuous progress of VR technology, space and time constraints are expected to be broken in fields such as e-commerce, live TV and social networking. "Digital avatars" can be used to improve the user's personality and even "go global shopping", giving the user a greater sense of presence. In order to achieve the above goals and expectations, the follow-up research still faces great challenges in terms of some key technologies and theoretical support.

reference

[1] Xu Shuo, MENG Kun, LI Shuqin, DING Meng, and Wu Lijun, "Overview of VR/AR Application Scenarios and Key Technologies," Intelligent Computers and Applications, Vol. 7, No. 06, PP. 28-31, 2017.

[2] EDNChina, VR boom: What are the three forms and the three key indicators? - EDN electronic technology design. [Online]. The Available: https://www.ednchina.com/article/10572.html (accessed: Sep. 28, 2020).

[3] Oculus, Gear VR Powered by Oculus: A Portable VR Device | Oculus. [Online]. Available: https://www.oculus.com/gear-vr/? locale=zh_CN (accessed: Sep. 28 2020).

[4] Oculus, Oculus Rift S: VR Headset for VR Ready PCs | Oculus. [Online]. Available: https://www.oculus.com/rift-s/ (accessed: Sep. 28 2020).

[5] HTC, find your high-end virtual reality equipment | VIVE ™. [Online]. The Available: https://www.vive.com/cn/product/#vive%20series (accessed: Sep. 28, 2020).

[6] PlayStation, PlayStation VR | PlayStation. [Online]. Available: https://asia.playstation.com.cn/chs-cn/psvr/ (accessed: Sep. 28 2020).

[7] Pico, Pico, A New Reality | | explore virtual Reality world. Pico VR machine [Online]. The Available: https://www.pico-interactive.com/neo2.html (accessed: Sep. 28, 2020).

[8] LIV, 【 Beat the Saber 】 If You Want to ESCAPE with Me LIV real machine demo _ bi li bi li (゜ ゜ つ ロ cheers ~ - bilibili. [Online]. The Available: https://www.bilibili.com/video/BV1dW41137ZM? from=search&seid=4177068583089805813 (accessed: Sep. 28 2020).

[9] C. J. Bohil, B. Alicea, and F. A. Biocca, "Virtual reality in Neuroscience Research and Therapy," Nat Rev Neurosci, Vol. 12, No. 12, PP. 752 -- 762, 2011.

[10] d. p. Wood, et al., "Virtual reality graded exposure therapy with arousal control for the treatment of combat related posttraumatic stress disorder: A Follow up Case Series, "Studies in Health Technology and Informa