Characteristic features of VR technology

VR is the computing field that aims at creating a virtual world, immersing and giving someone the capability to interact with this world, using special devices to simulate an environment and to stimulate the experience as genuine as possible through feedback. (Kalawsky, 1996). The basic characteristics of VR technology are discussed below

Immersion

When a person reviews a publication in the process of getting captivated by it, the person feels entirely soaked up by the publication details. Immersion is a sense of reality that can be offered by a media, in VR, there are three major types of VR (Kalawsky, 1996). Non-Immersive Solutions, such as Desktops, which is not an advanced tool for VR program, because they are affordable without the need for high performance, Fully Immersive Solutions, which provide

the customer with a close experience to reality with good quality visuals as well as efficiency along with a full or significant absence of unassociated stimulations, lastly, Semi-Immersive Systems which can be found in between full and non-immersive solutions (Moshell, 2003).

Flight simulators are Semi-Immersive Systems. The high-efficiency software program is being incorporated with stereoscopic vision, boosted field of view, haptic comments, to name a few virtual truth inducing innovations, to provide a much more immersive experience (Kalawsky, 1996).

Perception

Perception can be defined as the ability to be aware of the environment through the physical senses. Therefore, to give someone the feeling of something, visual sensations must be used.

The data-oriented method, which aims at immersion by data quality, is generally seen as two approaches, implying the closer a data looks like reality, the experience would feel more immersive. Which has been shown in higher resolution media interactions where more users had more immersion (Moshell, 2003). An approach called the constructivist approach engages the human ability to construct a reality, thereby being able to immerse one in technology without the engagement of high-quality technologies equipment.

Telepresence

The idea of Telepresence has always been used in VR technology; it is indicative of being able to sense a distant existence somewhere different from your actual environment. Marvin Minsky developed it in 1980 and is a term commonly in use by the VR world because it is closely related to the idea of immersion (Rheingold, 1991).

Interactions

The natural contact between the virtual scene and the user is referred to as interaction. It uses inputs to give users the same sensations as in the physical world.

2.2.2 Tools and technologies for creating virtual contents

VR technology is constantly evolving and developing within a very effective research environment (Vrais, 1998). All the most essential components of this technology for modern operating conditions are addressed in the following sections. the head-mounted display (HMD) which is a key feature that enables the realization of virtual reality, is advancing especially

quickly, with widespread predictions that weight HMDs and eyeglass size would be ready by the end of the century (Chien et al., 2003).

VR Training Core Technologies

This part summarizes the tools and technologies, which are the core foundations of VR-based simulation training studies:

(1) Adaptive technologies.

(2) Haptic devices.

(3) HMDs.

(4) Autonomous agents.

All of these four key components will be addressed in more detailed subsections in this section.

Training Content in adaptive technologies

Adaptation has become a key technology for VR-based learning, it interacts with a variety of user model including data stores and performance history, in other to give a critical connection that links all the systems. For instance, if a user communicates with a haptic system or autonomous agent, the stereo monitor output can be adapted in response. The motion tracking, eye tracking, and the system data of the adaptation of the haptic device can change the training level of difficulty to fit the skill level which will be taken into account by the trainee score assessment (Vaughan et al., 2016).

This segment summarizes the engagement of adaptive technologies to produce user-centric VR-based training content. Figure 1 shows the timeframe for technological improvement of adaptive solutions used in VR-centered training programs. The timeline shines a light on current trends and highlights important adaptation. Every timeline for this analysis reflects important changes between 1838 and 2010. The figure below is a timeline summarizing the history of technology, considering commercial, research and patent developments.

Figure 1. An Adaptive Technology within VR-based training Timeline of the development (Nguyen et al., 2020).

Haptic devices

Haptic systems are located across different areas, different techniques occur in vests form, like vibrato tactile components, while some are explicitly hybrid when they are incorporated as controls. These two approaches are often worn or form their subgroup (Ahlberg, 2003).

Contrarily, advances in the field of ubiquitous displays delivering haptic input have been undertaken, Virwind is an example of this.

Haptic feedback has been used throughout the VR process in other to enhance tactile skills, rendering VR particularly useful for gaining skills in a situation where touch and sensation are relevant. haptic forces can be manufactured in a wide range including torque, vibration, and resistance. These forces are applied in different degrees of freedom, typically three, six or more.

The consumer experiences haptic stimuli which are been determined by the frequency of the vibrotactile feedback and can be modified within different bandwidths; the typical frequency varies between 100Hz to 500Hz (Kang et al., 2015).

High precision technological haptic devices have become much more readily available.

Sensible gives access to a general-purpose instrument, known as Novintd, Geomatic, or Force Dimension which is a high precision technological haptic device. Haptic instruments have also been specially designed for specific educational purposes using gear motors, electromagnetic or electrostatic vibration effects (Kang et al., 2015) also by changing haptic devices like Novint Falcon (Coles et al., 2011). In the future libraries like immersion Haptic SDKF with a range of tactile effects will be supported in smartphones and tablets (Coles et al., 2011).

Figure 2. A fibre-optics wired glove Figure 3. The PlayStation Eye and two PlayStation Move controllers (Singh, 2003).

Even with the use of HMDs, eye, stereo graphics, and head monitoring, for traditional flat displays, a major drawback of VR realism is the absence of a vivid perception (Dargar, 2014).

Different types of methodologies have been used to produce stereo images, like head-mounted displays, holographic displays, shutter glasses and OLED screens (Dargar, 2014).

Head Mounted Display (HMD) devices also operate with eye-tracking or head motion tracking in parallel for increased realism. Both input and output machines are also HMDs. eye motion tracking, gyroscopes, accelerometers, and head motion tracking sensors are common example of inputs machine. Outputs consist of two graphic screens, with each eye having one. The inputs include data that are contextually rich that could be evaluated using computational intelligence algorithms in identifying activity patterns in the data. This knowledge is adapted to the development of adaptive content to personalize a unique experience for the different participant, calibration of the display is possible by using neural networks or optimization algorithms (Chen et al., 2014).

Figure 4 shows the trend for the technological advancement of HMDs or stereo graphics used in VR-based training systems.

Figure 4. Developed HMDs Timeline for VR-based training (Nguyen et al., 2020).

Mobile HMDs, in a lot of cases, hold a typical smartphone as a unit for data processing and display. They offer a clear scenario, where the phone is kept at a defined distance from the lens, the first devices of that type was created by google (Dondlinger et al., 2007). The Google Cardboard follows the ideology of serving like a very simple viewer, which doesn’t encourage the user to wear on the device. To have simple contact, the left side of the cardboard is fitted with a magnet, and the cell phone sensors sense the rotation of the magnet.

There is a significant number of carton copies that are in circulation and are inexpensive and perfect for delivering the technology. It also varies, for example, some lenses have a large FOV or mounting. More innovative alternatives are now being offered, equipped with a simple plastic case, back straps, or caps for mounting the cell phones. Samsung has produced high-grade smartphone holders in partnership with Oculus like GearVR7. The side case of the GearVR7 has an extra touchpad. Both Innovator Editions available and the version that was first released are exclusive to Samsung mobile. A new ergonomic smartphone holder is the Zeiss VR One8, which mostly supports both Samsung Phones and Apple Phones. Phone related slide-ins are used to place mobile devices within the case. Zeiss recently produced a variant adopting the path preferred by the VR One GX by google which is entirely compliant with Cardboard, which has no back strap features a magnet.

Figure 5. Mobile HMDs with three approaches. The Game face Mark IV (right), the Google Cardboard (left) and The Samsung Gear VR Innovator Edition (centre)

Figure 5 displays three cases of mobile HMDs. From the right side of the diagram shows the current version of the Game face systems a standalone smartphone VR device on the left side, the original Google Cardboard represents basic cases, the middle shows the Gear VR depicting ergonomic cases.