The terms "virtual reality" and "augmented reality" get thrown around a lot. VR headsets, such as the Oculus Quest or Valve Index, and AR apps and games, such as Pokemon Go, are still popular. They sound similar, and as the technologies develop, they bleed into each other a bit. But they're two very different concepts, with characteristics that readily distinguish one from the other.
What Is Virtual Reality?
VR headsets completely take over your vision to give you the impression that you're somewhere else. The HTC Vive Cosmos, the PlayStation VR, the Oculus Quest, the Valve Index, and other headsets are opaque, blocking out your surroundings when you wear them. If you put them on when they're turned off, you might think you're blindfolded.
However, when the headsets turn on, the LCD or OLED panels inside are refracted by the lenses to fill your field of vision with whatever is being displayed. It can be a game, a 360-degree video, or just the virtual space of the platforms' interfaces. Visually, you're taken to wherever the headset wants you to go—the outside world is replaced with a virtual one.
Tethered VR headsets, such as the Index and PS VR, and standalone VR headsets, such as the Quest 2, use six-degrees-of-freedom (6DOF) motion tracking. That tech comes courtesy of external sensors or cameras (for the Index and PS VR) or outward-facing cameras (for the Quest 2). This means the headsets don't just detect the direction in which you're facing, but any movement you make in those directions. This, combined with 6DOF motion controllers, lets you move around in a virtual space, with virtual hands. This space is usually limited to a few square meters across, but it's much more immersive than just standing still and looking in different directions. The drawback is that you need to be careful not to trip over any cable that connects the headset to your computer or game system.
For both games and apps, virtual reality supersedes your surroundings, taking you to other places. Where you are physically doesn't matter. In games, you might sit in the cockpit of a starfighter. In apps, you might virtually tour distant locations as if you were there. There are tons of possibilities in VR, and they all involve replacing everything around you with something else.
What Is Augmented Reality?
Whereas virtual reality replaces your vision, augmented reality adds to it. AR devices, such as the Microsoft HoloLens and various enterprise-level "smart glasses," are transparent, letting you see everything in front of you as if you are wearing a weak pair of sunglasses.
The technology is designed for free movement while projecting images over whatever you look at. The concept extends to smartphones with AR apps and games, such as Pokemon Go, which use your phone's camera to track your surroundings and overlay additional information on top of it, on the screen.
AR displays can offer something as simple as a data overlay that shows the time, to something as complicated as holograms floating in the middle of a room. Pokemon Go projects a Pokemon on your screen, on top of whatever the camera is looking at. The HoloLens and other smart glasses, meanwhile, let you virtually place floating app windows and 3D decorations around you.
This technology has a distinct disadvantage compared with virtual reality: visual immersion. While VR completely covers and replaces your field of vision, AR apps only show up on your smartphone or tablet screen, and even the HoloLens can only project images in a limited area in front of your eyes. It isn't very immersive when a hologram disappears once it moves out of a rectangle in the middle of your vision, or when you must stare at a small screen while pretending that the object on that screen is in front of you.
Basic AR that overlays simple information over what you're looking at can function perfectly fine with 3DOF. However, most AR applications require 6DOF in some form, tracking your physical position so the software can maintain consistent positions for the images it projects in 3D space. This is why the HoloLens uses a stereoscopic camera and advanced pattern recognition to determine where it is at all times, and why more advanced, AR-centric smartphones use multiple rear-facing cameras to track depth.
Augmented reality has nearly limitless possibilities. Phone-based AR software has been recognizing surroundings and providing additional information about what it sees for years now, offering a live translation of text or pop-up reviews of restaurants as you look at them. Dedicated AR headsets, such as the HoloLens, can do, even more, letting you virtually place different apps as floating windows around you. They effectively give you a modular, multi-monitor, computing setup.
Currently, AR is only widely available on smartphones and doesn't have the vision-augmenting aspect of enterprise-level AR displays. This means AR is still very limited until a consumer AR headset is released.
Summary
Virtual reality and augmented reality accomplish two very different things in two very different ways, despite their devices' similar designs. VR replaces reality, taking you somewhere else. AR adds to reality, projecting information on top of what you're already seeing. They're both powerful technologies that have yet to make their mark with consumers but show a lot of promise. They can completely change how we use computers in the future, but whether one or both will succeed is anyone's guess right now.
Article first appeared on PC Mag