AR, VR, Mixed Reality -- What's the diff?

Maybe you're confused. I certainly have been and I work in this industry. There are a bunch of different acronyms floating around to describe how computers can be used to create images to represent a simulated reality.  So what do they all mean and why is it important?  

"VR" or virtual reality is just what it sounds like: a reality that is completely virtual.  in this application, the computer creates the entire environment: the walls, floors, ceiling, objects, people... everything that the viewer experiences. Typically the user will don virtual reality goggles that block all vision and display the virtual environment on small computer screens placed right in front of the eyes.  Various sensors track the user's position and head movements so that the virtual environment responds accurately. The key here is that everything the user sees is virtual.  Recently I demoed a VR system that dropped me in the middle of an emergency department, while I was standing in the exhibit hall.  

"AR" or augmented reality is "computer assisted reality". What I mean by that is the user sees the actual world, either directly with their own eyes or though a video feed on the goggles they are wearing.  The computer then provides information, data and other display information or graphics that augment the reality, but are not part of it.  For instance, a worker in a warehouse might see a highlight around a box they are supposed to pull for delivery.

So, what is "mixed reality"?  This is similar to AR.  Again, the user sees the actual environment they are standing in, but while AR projects information and graphics that are not supposed to be part of the environment, mixed reality projects objects that are supposed to be part of the environment, but are not. PerSim™ is a perfect example of mixed reality.  For instance, a user wearing our system can be sitting in the back of the ambulance they work in on every shift, but we can place a simulated patient with severe respiratory distress on the stretcher.  

Each of these approaches has its benefits. The next entry in our blog will explore why we chose to use mixed reality for patient simulation.