While the three terms are often used interchangeably, there is a difference in virtual reality, augmented reality and mixed reality, which this article attempts to address.
Virtual Reality (VR)
Virtual Reality can be described as a digitally-generated simulation of an imaginary world to give an 'all-immersive' experience for the user. It could be an interactive experience as well.
Often available in the form of head-mounted displays, VR is typically used in computer games and entertainment like 3D movies, or for 360-degree videos which allow the users to view the video in any direction. VR is developed using the Virtual Reality Modelling Language, which is an open standard to create multi-participant interactive simulations like 3-dimensional vector graphics and web-based models.
Besides its use in games and entertainment media, VR can be also used for the purpose of training in a real life-like environment, such as simulators for drivers, pilots and astronauts. Virtual reality is also known to be used in 'exposure therapy' to treat patients with psychological conditions like post-traumatic stress disorders (PTSDs), by exposing them to imaginary anxiety triggers.
Augmented Reality (AR)
Augmented Reality is a live view of the real world, super-imposed by computer-generated (CG) content such as sound, visual graphics or GPS. The super-imposed CG data does not recognize or interact with the real world content.
AR is made available in the form of digital components in mobile devices like smart phones, laptops and tablets. You will notice AR being used while displaying score overlays in telecasted sports games.
The heads-up display used in military forces is another example of augmented reality, where fighter pilots at higher altitudes, use a transparent device, which when positioned appropriately displays critical data such as altitude, airspeed and the horizon line, without the need to look at the aircraft's instrumentation.
Mixed Reality (MR)
Mixed Reality, like Augmented Reality, is also a computer-generated experience, however, the virtual content is not only overlaid in a real world atmosphere but also merges with it to make it a hybrid reality. In the world of mixed reality, the digitally-generated content react and interact with the real world environment.
Microsoft's HoloLens and Google Glass are two such mixed reality inventions that use holographic computing technology. Pokémon Go, which had recently become a phenomenon in mobile gaming is a location-based mixed reality game. MR also makes it possible for surgeons to overlay virtual ultrasound images on their patients while performing operations.
So to summarize, while Virtual Reality (VR) recreates an imaginary environment for its user, Augmented Reality (AR) and Mixed Reality (MR) simply augment the real-world view by super-imposing digital content like interactive graphics and sound sensations. They are together considered one of the most evolving and sought-after technologies.