In a Nutshell:
AR makes use of mobile technologies to enhance physical locations and objects with digital information in various formats, including text, audio, video, web content, social media links, 3d modeling and animation using markers and more recently geolocation and geotagged entries, or products using interactive print ("DIY," 2013).
AR has primarily been used in the consumer sector for marketing, social engagement, amusement, or location-based information. The New Media Consortium Horizon Project notes that “new uses seem to emerge almost daily, as tools for creating new applications become even easier to use” (Augmented Reality, 2013).
In Augmented Reality, A Practical Guide, Cawood and Fiala provide a helpful overview of Marker vs Markerless AR and the difference between the Magic Lens and the Magic Mirror viewpoints.
Marker vs. Markerless AR
Marker AR has been around for a long time and uses printed markers at a location and software to recognize programmed objects when the markers are viewed through a camera. When the marker (or image) is viewed through the camera lens, the software overlays the virtual object on top of the camera image and the user can see the augmented image (Cawood and Fiala, 2008, p. 15). QR-codes are one common form of marker AR, linking the physical and digital. If viewed through a mobile device connected to the Internet, users can also interact with content using interactive print functionality.
Markerless AR is created without using markers, and instead uses distinctive features (edges, corners, textures) in real objects within the environment (Cawood and Fiala, p. 16). Markerless AR technology is becoming more common as "simultaneous localization and mapping" (commonly referred to as SLAM) advances (Carson, 2014), but it still pretty far away for the average user to create.
Magic Lens vs. Magic Mirror
There are two perspectives for viewing AR. The magic mirror technique is often used to display augmentations via real-time video, and are displayed behind the area being captured using a projection screen. Viewers can stand in front of the display and watch as the augmentation is happening. The Live Augmented Reality for the National Geographic Channel video in this guide is an example of the magic mirror technique (Cawood and Fiala, p. 13).
The magic lens view allows users to "see through to an image of the real world with added AR elements" (Cawood and Fiala, p. 14). The Cimagine Augmented e-Commerce Solution video in this guide is an example of the magic lens viewpoint.