How does AR work?

There are several ways to augment reality that utilize two main approaches to gather data to augment reality.The first approach is based on the postioning of visual cues or "markers" including gestures or movements that are seen by a camera on a computer or a mobile device. The cue or maker is interpreted by software on the computer or device and brings up information in reponse to the position of the markers. The second approach is to interpret the location of a mobile device and the character of the objects in the field of view of the mobile device.
The ability to recongnize a variety of objects and movements is continuing to evolve and become more sophisticated, increasing the power and scope of this technology.2011 Horizon Report

To experience AR there are only three main requirements you need for AR to function: first a smartphone with a camera to capture reality; second, a connection to the Internet for receiving the layer of information and; third software on your phone to bring it all together. It also helps to have a phone with GPS and a compass so it knows which direction you are facing.

The following Describes some of the major AR trends.

Augmented Reality in Education

Gesture Based Computing
The 2010 Horizon Report refers to Gesture based technology as technology that enables humans to interact with mechanical devices using simple natural gestures. An example of this technology is Sixthsense. Sixthsense is a wearable gestural interface device by Pranvan Mistry, a PhD student in the Fluid Interfaces Group at the MIT Media Lab. Sixthsense Another early example of gesture based computing is the Nindento Wii. The systmem accepts input in the form of taps, swipes, and other ways of touching, hand and arm motions, or body movement. external image WiiBy_doou.jpg

Geotagging and Geolocation
Geotagging and Geolocation are fast emerging trends in digital photography and community sharing. Geotagging or georeferencing is a process of adding geographical information to various media such as images, videos or text in websites, blogs or photosharing, to help us find a wide variety of location specific information. A Geo tag is like embedding the time and date a photo is taken, execpt the GPS location or compass direction can be embedded thereby tagging the image. Lou et al. An example of an AR application is when we access Google Earth to view a location, we are now able to find pictures and information added by users through these types of tags.
image of pictures tagged to google earth map
image of pictures tagged to google earth map

AR markers
Many people associate Augmented Reality with black and white squares such as QR Quick Response codes or Semacodes that trigger Augmented Reality elements. These black and white squares are called markers. A QR code is a two dimentional bar code that allows its content to be decoded at high speed
.What is a QR code

Augmented Reality Browsers
Browsers utilize GPS, mobile phones, cameras and computers to identify a person's location and then the user can retrieve information based on geographic co-ordinates. Layar was one of the first AR browsers initially released for Android phones in the Netherlands. In 2009, it was launched globally for Android, and it is now also available for the iPhone. In Layar, augmented data is stacked in layers. The user can click to view different layers of information. For example, if the user points a smartphone camera at a building, there may be a layer for architectural history or a layer to find a restaurant and an another layer may even give the user access to the restaurant menu inside the building.Layer

Another example of browser is Wikitude.
Wikitude browser on iOS
Wikitude browser on iOS

Wikitude is a free downloadable browser application for iPhones and Android phones that was developed in 2008. The browser allows users to access data about their surroundings, nearby landmarks, and other points of interest by overlaying information on the camera-view of their Smartphone. When the user first downloads the Wikitude browser, it asks if it can use the user's current location to find information relevant to that location. With the geolocation data and internal compass, the browser then presents a list of Worlds and Points of Interest (POI) The user next enables their smartphone camera and points it to buildings or areas of interest. Wikitude Wikipedia