# Extended Reality: Types and Applications
## 3 Applications of Extended Reality
### Extended Reality and Its Usage
#### 3.1.3 Mixed Reality and Its Usage  
Mixed reality is about the same as augmented reality but more interactive with augmented and real environments. Augmented reality usually only shows content and the tracking position of the viewing device. Mixed reality usually involves an HMD headset with a set of color and time of flight (ToF) cameras and hand spatial controllers [57]. Overall, mixed reality systems can make a 3D scan of the environment [58] and recognize real objects, which allows users to interact with them with virtual assistance.  
* Education--MR system can be used for fast teaching of new employees and checking their work for errors [59; 60]. Using the technology of a digital twin of the robot or other machine, it is possible to study in a half-real environment, for example, a simulation of a virtual production line with a real robotic manipulator or a simulation of human safety and ergonomics [61].
* Production Planning and Maintenance--The use of mixed reality technology has found its application in Industry 5.0 concepts, where the emphasis is on the interaction of humans and machines (Figure 6). This concept has become an incentive for the development of collaborative robots (cobots). They are increasingly used in modern production to improve and ensure the necessary safety of workers during work [62].  
Conventional robots used in manufacturing are often dangerous because they may run at high speeds, handle dangerous attachments, work in hostile environments, or lack sensors to detect human actions that could be dangerous to the person. Collaborative robot control systems are about the same as regular robot systems but with extra safety and XR features that add the possibility to work together with people [63]. These systems can use a HMD or projector to show the operator work instructions, what the robot plans to do, and its status, to prevent accidents. [64]. For example, conventional robots in production simply turn on a pre-trained program with possible correction using data from sensors. Adding a system of cameras and sensors, as well as a special controller, allows artificial intelligence to track human actions and facilitates safe interactions between humans and robots [61]. Robots used for such tasks usually have lower speed and power. This allows them to be used for simple tasks that can help a person, such as easing the movement of objects or packaging. One example of MR usage is the digital twin method of communication between robot and user.  
* Military and Rescue Applications--Mixed reality can be used for reconnaissance, automatic creation of a map in real-time, and interactive control of a robot for military purposes or for rescue operations when it is necessary to safely explore a location with rubble and find people, for example, after earthquakes. The article [40] shows a method for interactively visualizing a real-time map and the robot's position, as well as an intuitive way to specify points for the robot to move.  
Research performed on the subject reveals that augmented reality is an excellent method of visualizing virtual objects in the real world and interacting with both worlds using hand gestures or spatial controllers. In addition, there are a lot of applications such as education, production, and military. MR helps in collaborations with cobots by simplifying and accelerating the understanding of robot tasks, learning, experimenting, and conducting simulations interactively.