Augmented Reality (AR) and Virtual Reality (VR) are sometimes confused in conversations, but in fact they have only one thing in common: the word “reality”. Otherwise, they are completely different.
- They are used for different purposes.
- They use different technologies.
- And, not least of all, augmented reality is much, much harder to do.
In this post we will look primarily at differences in the way the two technologies/services are used. In a subsequent post we we look more closely at differences in technologies and the added complexities in implementing augmented reality.
Ok. Saying augmented reality and virtual reality are “completely different” may be a bit of an exaggeration. Both use computers and both can be used for entertainment. Both commonly use graphics and animations. And both can be interactive.
The best example of augmented reality is the yellow first down line in TV broadcasts of American football games. That line doesn’t actually exist on the field and if you’re sitting in the stadium there’s no yellow first down line to see. The line is added digitally in the few seconds between the time a TV camera at the stadium takes in an image of the game and the time the image is reproduced in your living room or sports bar. The heads up displays used by pilots are also forms of AR. Augmented reality adds digitally supplied images or information to real world images.
Virtual reality, on the other hand, completely removes all traces of or 
connections to the real world and replaces the real world with a digitally produced artificial world. Second Life, Cloud Party, and games such as World of Warcraft are virtual worlds that can be accessed using an ordinary computer, but if you’ve ever been exhilarated by a ride on Disney’s Star Tours, you’ve experienced immersive virtual reality, which stimulates all your senses.
Not so long ago, the term “virtual reality” encompassed both VR and AR. Before distinctions in technology and application separated them, science fiction authors such as William Gibson, used the terms interchangeably. The popular press continues the practice, but, as the two services have become more commonplace in both professional and entertainment applications, the distinction is apparent to more people. Even the definitions of VR and AR provided by Wikipedia differentiate between them appropriately.
Today, VR is primarily a means of entertainment. MMOG (massively multiplayer online games), for example, take place in virtual worlds in which thousands of players (massively multiplayer) are participating in the same online game at the same time. The worlds of World of Warcraft, Final Fantasy, and Starcraft are very complete universes that replicate many features of reality, including complex histories, large geographies, and constantly shifting socio-political rivalries. These virtual worlds include mountains, prairies, plants, animals, buildings, and “intelligent” beings (non-player characters or NPCs), many of which respond to interaction. Players visit these worlds to entertain themselves both through interaction with the virtual worlds and through interaction with other players.
Increasingly, large government organizations such as NASA and global corporations such as IBM, BP, and SAP use virtual world technologies to facilitate communications between employees and or with service partners who are separated by either geographic or time zone differences. These programs reduce costs, increase cooperation and innovation, and improve time-to-market.
Augmented reality, on the other hand, is far more likely to be used to provide basic information. The yellow first down line in TV broadcasts of football games also provides information that facilitates the enjoyment of the game, but it’s still providing information: the line itself is not a form of entertainment. Star Walk is a smartphone app that allows you to point your camera to any part of the sky, day or night, and see what constellations, satellites, or planets are in that part of the sky. As you move your camera, the information adjusts in real time. Many people might find this “fun,” but they are more likely to consider it informative.
In augmented reality, virtual objects may be interactive and respond to clicks or gestures, but interaction with the objects is a means to an end.
Clearly, even the shared word “reality” refers to something very different in virtual and augmented realities. The reality of AR is the same reality that everyone experiences through their senses from the moment they have consciousness. We can modify and manipulate it, but it exists independent of human creative efforts. A virtual reality, on the other hand, exists solely because someone or a group of people conceived of it, designed it, and created the computer programs that bring it to life. Humans may use their senses to interact with a virtual reality, but in addition to their senses they need some sort of interface (a mouse, a keyboard, a gesture interpreter, a display) that allows them to experience and interact with the virtual world.