1 Introduction

With the rapid development of computer software and hardware technology, virtual reality technology came into being and developed rapidly on the basis of the maturity of computer graphics theory and digital image processing technology [1, 2]. With the help of computers, a virtual environment which is very realistic with the real environment is constructed, and it supports users to experience personally with natural skills. Currently, it has been widely used in the fields of military, scientific computing visualization, education and training, design and planning, virtual testing, virtual tours, shopping, interactive entertainment, engineering technology, scientific and technological exploration and so on.

Under the background of the Internet of Things, the most remarkable feature of virtual reality technology in practical application is immersion. It is to upgrade the landscape communication consisting of existing words, images, videos and so on to a spectacular and immersive experiential transmission of “feeling of experience” [3, 4]. This is undoubtedly a highly disruptive technological change, and it may even directly lead to changes in the existing state of many industries [5, 6]. Companies and entrepreneurial teams in information technology, health care, education, tourism, entertainment, e-commerce and other industries are involved in the field of virtual reality, including large-scale technology companies such as Microsoft, Sony, Google, and research institutions such as Goldman Sachs and Deutsche Bank; they are optimistic about the development of the global virtual reality industry [7, 8]. However, virtual reality is not a real world, but an alternate environment that people can enter and interact with through various media of the computer. Essentially, virtual reality is an advanced computer–user interface that maximizes the user’s operation by providing users with intuitive and natural real-time perception interactive means such as visual, auditory, touch and so on, thereby reducing the user’s burden and improving the efficiency of the whole system. As an emerging science and technology, virtual reality technology is also the product of comprehensive cross-integration of many related subject areas [9]. Its research involves artificial intelligence, computer science, electronics, sensors, computer graphics, intelligent control, psychology and so on. The new human–computer interaction technology represented by virtual reality technology aims to explore natural and harmonious human–computer relationship and develop the human–computer interface from visual perception to multisensory perception including vision, hearing, touch and olfaction, and also from manual input to a variety of effects channel inputs including voice, gesture, posture and line of sight. However, the current development of virtual reality technology is far from what people expected.

It can be seen that in the environment of the Internet of Things, the development of the virtual reality industry cannot be rushed for success. Only with a solid technical foundation, the long-term vitality of the industry can be guaranteed.

2 Literature review

Park et al. [10] have found that people have begun to make efforts to achieve mixed reality, interweaving the real world and virtual world. Recently, in the past few years, we have witnessed the first wave of “affordable” mixed reality platforms, such as Oculus River and Microsoft HoloLens, entering the market. In particular, 2017 was the year of hybrid reality technology: The first Oscar was awarded for virtual reality storytelling; AAA VR games began to be affected. In addition, major mobile operating systems, including Android and iOS, have begun to support augmented reality at the platform level (for example, Android ARCore and Apple ARKit). Coogan and He [11] found that with the emergence of virtual reality (VR) systems and the Internet of Things (IoT), these technologies can be combined to provide real-time control of user’s virtual and physical environment. Similarly, BCI applications are usually used singly, and users cannot control them beyond the application’s limitations at the time of creation. Therefore, it is necessary to create a tool that allows users to flexibly create and modularize all aspects of BCI applications to control Internet of Things devices and VR environments. By utilizing the popular video game engine unity and coupling it with BCI2000, we can create a variety of applications that give end users additional autonomy in the tasks at hand. We processed the direct neural interface by BCI2000 and proved the effectiveness of controlling the unity-based VR environment and several commercial Internet of Things devices. Research by Zhang et al. [12] shows that virtual geographic environment cognition is an attempt to understand human cognition of surface features, geographic processes and human behavior, as well as their relationship in the real world. From the perspective of human cognitive behavior analysis and simulation, the previous work of virtual geographic environment (VGE) mainly focuses on the performance and simulation of the real world to create an “interpretative” virtual world and improve the individual’s active cognition. In terms of reactive cognition, it is a necessary but challenging task to construct user’s “evaluation” environment in complex virtual experiments. Cecil et al. [13] showed that virtual reality-based simulation environments include tactile-based interfaces that support collaborative training and interaction between expert surgeons from distributed locations and residents from plastic surgery. They also studied the impact of using this medical education framework based on medical Internet of Things, and the findings highlighted the potential of adopting this Internet medical education approach based on medical items. Research by Cheng et al. [14] shows that one of the key issues in the development trend of CPMS is the Industrial Internet of Things (IIoT), which has the characteristics of automation, intelligent connection, real-time monitoring and collaborative control. With the penetration and application of advanced technologies in manufacturing industry, a large number of data have been generated in the manufacturing process. Ai et al. [15] have shown that with the rapid development of mobile Internet and Internet of Things applications, traditional centralized cloud computing has encountered severe challenges, such as high latency, low spectral efficiency (SE) and non-adaptive machine-type communication. To solve these challenges, a new technology is driving the trend of transforming centralized cloud computing capabilities into network edge devices. Several edge computing techniques have emerged which originate from different backgrounds to reduce latency, improve SE and support large-scale machine-type communications. Mendes et al. [16] showed that in order to understand the potential of big data and Internet of Things in manufacturing companies, we investigated the production process of auto parts companies. Currently, data is collected manually and automatically. Other types of data are automatically recorded by the information system. Different systems are used to record and process data according to the location of data collected in the production process.

3 Application of virtual reality technology in the background of Internet of Things

3.1 The conception of virtual reality technology under the background of research

The Internet of Things (IOT) is a kind of network connected with things. It includes two meanings: One is that IOT is a network extended on the basis of the Internet, and its core is the Internet; the other is that its user end has been extended, not only to communication between people, but also to the exchange of information between people and things, things and things [17]. The advantage of the Internet of Things is that it is not limited by region. Its nodes are small in size and can be distributed in any harsh environment, enabling information to transfer between objects.

Under this background, virtual reality technology is an emerging technology based on a number of core technologies, including three-dimensional graphics generation and dynamic environment modeling, system application development and integration, stereo display and real-time sensor production and so on. Through the integration of various core technologies, it can solve various problems faced by users, such as the real-time transmission of the environment, three-dimensional dynamic graphics generation and intelligent equipment wearing. The purpose is to create a realistic “presence” for users, so that users can feel the virtual environment as if they do in real life, and guide users to understand and explore the “new world.” In order to achieve this goal, researchers and designers must further improve the authenticity of virtual environment simulation reality, the accuracy of user-perceived information synthesis and the fluency of human–virtual environment and human–human interaction [18]. At present, the main features of virtual reality are 3i features (i.e., conceptual Imagination, Immersion and Interactivity).

The so-called conception means that the environment in virtual reality is not real, but based on the designer’s imagination or different perceptions of objective things. Therefore, the virtual environment can also reflect the designer’s value orientation and achieve certain goals. From this point, virtual reality technology has been separated from the category of pure media or entertainment tools, it can also be used to solve problems in medical, engineering, military and other fields [19]. The appearance of virtual reality technology provides us with an unprecedented perspective of understanding and transforming the world. It enables humans to cross the physiological barrier and enter the inaccessible macro- or micro-world to carry out research. It also enables us to break through the limitations of time and space, to “real” touch and feel what has already happened in the world or is difficult to accomplish because of conditional constraints.

$$x^{\prime} = h_{1} \left( {x,y} \right)$$
(1)
$$y^{\prime} = h_{2} \left( {x,y} \right)$$
(2)

Formulas (1) and (2) describe the relationship between the coordinates of things in the Internet of Things.

Different interaction modes directly affect the efficiency of information transmission and user’s experience comfort in interactive behavior. Early in the 1960s, the interaction between people and computers was mainly based on the command line interface. The only way for users to operate a computer was to input commands through the user’s keyboard. Users needed to remember a large number of operation commands, so there was hardly any natural interaction. Mutual efficiency was also very low, which was not essentially different from the switches and keys on the earlier operation control panel.

With the rapid development of three-dimensional technology, virtual reality technology and the Internet of Things, Fig. 1 shows data research in the field of virtual technology under the Internet of Things.

Fig. 1
figure 1

Data research in the field of virtual technology under the Internet of Things

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Traditional two-dimensional maps are constantly updated and developed. Three-dimensional maps gradually appear in the public’s vision. The three-dimensional effect brings people more reality and friendly interface, which is more vivid and more powerful than two-dimensional maps. Compared with the two-dimensional maps, the three-dimensional maps are more abstract to the real geographical information, and the three-dimensional maps show the intuitive real world, and the simulation effect is more realistic [20]. The functions and features of three-dimensional maps displayed by the system are as follows: (1) Stereoscopic: Three-dimensional maps provide users with a sense of three dimensions, and various geographical elements need to give a sense of depth when displayed on the map. (2) Directivity: The three-dimensional maps support rotating operation, which makes it easy for users to observe the real geographical panorama dynamically and comprehensively. (3) Intuitive: The essence of three-dimensional maps is to simulate human vision and display actual maps and clearly obtain geographic information. (4) Authenticity: The three-dimensional maps made by space utilize satellite image data as basic data and provide the most direct and real scene through virtual reality technology.

3.2 The immersion of virtual reality technology

The so-called immersion refers to the “sense of reality” perceived by the users in the virtual reality environment. Users will be completely in the virtual world when they use the devices. All sensory perception, in addition to the common visual perception, as well as auditory perception, tactile perception, taste perception, olfactory perception and so on, will be immersed in the virtual world, because “olfaction, taste, touch and so on still have some auxiliary effects in people’s aesthetic activities.” Making users a part of the virtual world is the most important technical feature of this technology, even if the world is only the data stream created by computer systems. Figure 2 shows real-time interactive data between virtual networks and the real world under the Internet of Things; this immersion makes users immerse in the virtual world and enjoy activities in it and ultimately transforms users from peripheral observers into active participants [21]. In theory, virtual reality system should be able to realize all the perceptual functions of human beings in reality, that is, all the sensory perceptions mentioned above. However, the technology development is not mature at present. Visual immersion, auditory immersion and tactile immersion have been realized in the current research and application of virtual reality system, but the technology of taste perception, olfactory perception and mechanical perception still need further efforts of researchers.

Fig. 2
figure 2

Real-time interactive data between virtual networks and the real world under the Internet of Things

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According to the IoT technology, the control structure of the combination of upper and lower computers is adopted. The bottom sensor devices are connected with lower computers. The upper and lower computers interact through serial communication. Modbus protocol is used as communication protocol, and Ethernet is used as transmission network between upper computers and remote computers. Formulas (3) and (4) describe the calculation of virtual reality location in the Internet of Things.

$$C\left( {s,t} \right) = \sum\limits_{x} {\sum\limits_{y} {f\left( {x,y} \right)} } w\left( {x - s,y - t} \right)$$
(3)
$$I_{2} \left( {x,y} \right) = I_{1} \left( {x - t_{x} ,y - t_{y} } \right)$$
(4)

Transferring on the basis of TCP/IP protocol, the system structure diagram of virtual reality technology research in the Internet of Things is shown in Fig. 3.

Fig. 3
figure 3

System structure diagram

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3.3 Real-time interactivity of virtual reality technology

In the environment of Internet of Things, the real-time interaction of virtual reality technology means that users can operate objects in virtual reality and get feedback from the natural environment, and even communicate directly with people in the process of using it. Virtual reality underlines the natural interaction between human and virtual world, human and human, because it will strengthen the immersion of virtual reality. This interaction should be real time. At present, this kind of real-time interaction is mainly generated by means of special hardware devices, such as data gloves, so that users can naturally emerge the same feelings as they are in the real world. Figure 4 shows the human–computer interaction in virtual reality technology.

Fig. 4
figure 4

Human–computer interaction in virtual reality technology

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3.4 Research on database design

The three-dimensional interactive control system divides the database into spatial and non-spatial. Spatial database is stored with the system-requested spatial data, which mainly describes features of spatial objects, such as the location and size. It reflects the nature of location and spatial relationship. In the non-spatial database, it is the attribute data of the system, which is used to store user information, collected data and so on. Separate storage aims at making it easy for the system data management.

There are two formats when stored in the PostgreSQL database, one is geometry format and the other is shape file format. Relevant data of the experimental station system can also be stored in CSV files. With the application of QGIS, the CSV format and shape format files can be converted to each other. Normally, two databases will be built in the PostgreSQL database, one is spatial database and the other is common database. The spatial database is used to store spatial data. If some data in the system is not regarded as spatial data, a common database can be built to store common data. Separating into two databases like this is the requirement of spatial data and is helpful for management. The plug-in related to the open-source PostgreSQL database is PostGIS. PostGIS is a spatial data engine. It is simple and time-saving to update data with this plug-in. For example, when updating data, first, prepare the data file with shape format, and then use PostGIS to import the data step by step into the corresponding data table. The field name of the shape file data should be consistent with the field name of the corresponding data table, in order to ensure the final import success.

$$G_{L} \left( {i,j} \right) = \sum\nolimits_{m} {\sum\nolimits_{n = 1}^{5} {w\left( {m,n} \right)G_{l - 1} } } \left( {2i + m,2j + n} \right)$$
(5)
$$L_{k} = G_{k} - {\text{EXPAND}}\left( {G_{k + 1} } \right)$$
(6)

As it shows in formulas (5) and (6), bandpass-filtered image layer and high-resolution image layer are obtained by calculating the difference between the images, this makes the virtual reality world to be more real.

Hybrid structure: It utilizes two subsystems to store spatial data and attribute data, respectively. Attribute data is stored in the general relational database management system (RDBMS), and geometric spatial data is stored in the spatial data management system. The two systems are connected by a unique identifier. The fundamental frame diagram is shown in Fig. 5. This hybrid structure of data storage and retrieval is an efficient and reliable graph. However, because it utilizes two storage subsystems, which have their own rules, thus it is difficult to optimize the query process.

Fig. 5
figure 5

Hybrid structure diagram

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Extended structure; when the spatial data management layer is added to the standard relational database, the same database management system (DBMS) is used to store spatial data and attribute data. The advantage of this structure is that the complex connection between spatial data and attribute data is omitted, and the efficiency of accessing spatial data is very fast. Because this structure is indirect access, it is generally less efficient than the operation process used in DBMS, and the query process is complex. The extended structure diagram is shown in Fig. 6.

Fig. 6
figure 6

Extended structure diagram

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Document and relational database hybrid structure: Data files are generally in shape format, spatial data files are stored in the document management system, while attribute data files are stored in the relational database management system; two data files are associated according to the identification code, and the general identification code is D.

The advantage of this structure is that spatial data and attribute data can be completely independently managed and retrieved. Since the data is stored separately, good security and integrity cannot be guaranteed. Figure 7 shows document and relational database hybrid structure.

Fig. 7
figure 7

Document and relational database hybrid structure diagram

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The association between spatial data and attribute data is carried out by specific coding. Generally, this specific coding chooses the main item of a table, which has the characteristics of uniqueness and non-emptiness. If a geographic element exists in a table, a main item which is non-duplicated will be added to the corresponding association table.

4 Research on the data processing of virtual reality interaction technology in system

4.1 Data preprocessing of virtual reality interaction technology in Internet of Things

The purpose of data processing is to disassemble the gathered information into normal minimized fragments. Many analytics platforms can be preprocessed to form an integrated tabular file such as .CSV (Comma-Separated Values) or .XLS (Microsoft Excel Worksheet) files. These documents are usually tabular to the original information, except for the differences in the presentation of information layout, and the content itself has not been processed. The analysis platform will process on the basis of this basic information more finely to meet the demands of its main analysis services; however, the processed data will not be directly provided to users. If you need to analyze on the basis of these data, you need to rely on utilizing the analysis platform. However, the problem is that its analysis method is universal and established and it cannot be applied to customized analysis. It is unfavorable to targeted analysis or exploration of new analysis methods.

$$R_{x} = \left| {f\left( {x + 1,y + 1} \right) - f\left( {x,y} \right)} \right|$$
(7)
$$R_{y} = \left| {f\left( {x + 1,y} \right) - f\left( {x,y + 1} \right)} \right|$$
(8)

Data can be processed by themselves through formulas (7) and (8). Different analysis methods and tools can be used flexibly to produce more effective analysis reports. This research uses technology to collect data, providing data support for the realization of interactive control of the Internet of Things. Figures 8 and 9 show the collected data and data fitting, data1–data4.

Fig. 8
figure 8

Data statistics

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Fig. 9
figure 9

Data forecasting model

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Data1–data4 represents data collected by different methods and tools in the Internet of Things.

Data fitting represents a fitting of data collected in the Internet of Things.

The output is based on the preprocessed data level as shown in the graph above. In the process of data processing in the prediction model, the facticity of virtual interaction in the environment of Internet of Things can be achieved.

Its gradient in the environment of Internet of Things can be expressed by formula (9).

$$g\left( {x,y} \right) = \left| {R_{x} } \right| + \left| {R_{y} } \right|$$
(9)

Different information is recorded in a specialized record term. Figure 10 shows preprocessing data data1–data4 and fitting data. The results of data preprocessing indicate that this structured organization facilitates the search, collection and analysis of information. However, according to the data exported from the retrieval platform, there are many problems that need to be solved in the well-arranged table files. These problems include: (1) different representations of the same object, (2) several data which cannot be consolidated processed in a single cell, (3) information loss and (4) customized information needs to be added in addition.

Fig. 10
figure 10

Data preprocessing results

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4.2 Virtual reality technology Human–Computer interactive data transmission in environment of Internet of Things

After completing data collection, the sensor should transfer these data to the server. Data transmission is very important in the whole system so that efficient, high-speed and timely transmission of data information should be taken into account.

Modbus protocol is an application layer protocol, and data transmission is to form a unified system with different physical connection networks through this protocol. Modbus protocol is responsible for communication between devices, and this certainly requires devices to support Modbus communication protocol. The client sends a Modbus request to the server, and after receiving the request, the Modbus server begins the analysis of the incoming data model. Figures 11, 12 and 13 show the data sets of Modbus protocol data transmission.

Fig. 11
figure 11

Data sets (1)

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Fig. 12
figure 12

Data sets (2)

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Fig. 13
figure 13

Data sets (3)

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The result of the operation indicates that the cluster takes more time than the single machine, and with the increase in the nodes, the time will not change too much. Moreover, the cluster time has decreased with the number of nodes increasing, and the cluster time and the single-machine time have both increased. However, the cluster takes less time than the single machine, and with the increase in the number of nodes, the time decreases fairly quickly.

As can be seen from Fig. 14, as time goes by, the transmission efficiency of data transmission system with middleware is obviously better than that of traditional transmission mode.

Fig. 14
figure 14

Comparison chart of transmission efficiency

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After Modbus accesses the incoming data, the data fusion process stores the data1–data2 and data fitting in device application memory, as shown in Figs. 15, 16 and 17.

Fig. 15
figure 15

Comparison chart before and after data fusion

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Fig. 16
figure 16

Comparison chart when there is no data fusion

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Fig. 17
figure 17

Comparison chart when there is data fusion

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In the environment of Internet of Things, for individual audiences, virtual reality creates a relatively closed interactive virtual environment, the information it received is huge and complex and difficult to supervise. Therefore, we should not only consider the security of production and market, but also protect the information security of citizens and strengthen the management of information and data together with the supervision of information dissemination channels. Therefore, the formulation of product standards should not only focus on production processes, but also on data collection, data flow, application range and so on.

Only by providing detailed instructions on data collection and data usage of virtual reality products and establishing data management system, we can ensure data security and efficient utilization, protect citizens’ and industrial applications and secrets from being leaked and, at the same time, enhance the efficiency of information transmission to a new height.

5 Conclusion

In the environment of Internet of Things, the research on virtual reality technology and its unique immersion has created a fantastic way of communication, that is, immersive transmission. With the promotion of virtual reality technology, a new opportunity has come into being, that is, changing the traditional status to re-engage the audience through VR. In this sense, virtual reality technology is revolutionary. The transmission content and effect of virtual reality in the Internet of Things is undoubtedly historic. Just like the emergence and development of network media, it will continue to subvert the inherent patterns of many industries and further integrate them.

Limited in time and energy, this paper does not discuss all the technical fields of virtual reality technology, but selects the technologies related to human–computer interaction for analysis. Therefore, it may lead to the deviation of the follow-up analysis results. In addition, there are omissions in data cleaning. A variety of analytical tools has been utilized to visualize the analysis as far as possible, in order to reveal the complex relationships in the data. However, due to the limited accumulation of information and knowledge, many analyses are in the situation of incomplete analysis or omission of important points. In the future, we will improve our work by big data technology [22, 23].