Human beings have tried to realize things in devices or in reality. As a result, they have drawn things in paper, taken pictures, made videos, and finally printed things in 3D. In addition to these attempts, human beings have tried to move reality itself or more than reality to devices. Developments in devices and technology related to computer science are bringing reality into devices. The main technologies of the realization of the reality are Virtual Reality (VR) and Augmented Reality (AR).
VR is defined as technology that realizes imagined space and things through computer space and provides indirect experiences  for human sensory through a head tracker, eye tracker, tracker, speech recognition system (sound), pressure detector (feeler), etc. This up-to-date technology is based on computer graphics, computer vision, artificial intelligence, etc. As the purpose of VR is to make users immersed in VR to the extent that they have a sense of being there, VR is used for people to experience things that cannot be achieved in reality. For that reason, training programs in the military and in other dangerous occupations use VR with head-mounted display, data suits, data glove, or VR weapon. In actual life, mainly, VR is known with Oculus that creates 3D surroundings via an eyepatch-like device.
“Augmented” embraces what AR means. AR is a subsector of VR, but AR provides a somewhat different interface. If user is in a room, VR devices create other worlds (like Everest, Arctic, Hawaii, etc.). On the other hand, AR devices show the room itself, but in an augmented form. For example, if some furniture exists in that room, by the AR devices, information of that furniture is provided as a hologram. Current popular AR technology is Pseudo-AR, which draws 2D information onto real space using hardware sensor information of mobile device. For the development of AR, Context-Aware Mobile Augmented Reality has been researched. The technology focuses on the recognition of things and application of AR on those things.
Through AR and VR, visualization of data to population, 3D simulation of game especially virtual match, direct participation in education, simulation system in astronomy, etc. will be achieved in every single field. That is to say, all imaginable things, including complex systems, could be seen through those technologies. Recently, Apple released a VR head phone for Apple users, which means major companies consider VR and AR have potential. In the other words, they will be infinitely developed in the near future.