Augmented reality (AR) is a very old technology dating back to the 13th century when the eyeglasses were invented. But, today's augmented reality is a whole new thing. Augmented reality is about technology that perceives the environment, the user's interactions with the environment and displaying to the user a modified (augmented) view of the environment. This technology has shown a tremendous progress over the last few years and a great deal of research and resources go into moving it forward even faster. Google's cyborg lens and Microsoft HoloLens are examples of heavy hitters investing seriously in AR. Facebook, with its acquisition of Occulus Rift, is in the running as well and has plans for AR glasses. Apple is also working on augmented reality and don't forget Sony with its SmartEyeglasses.
Augmented Reality vs. Virtual Reality
Virtual reality (VR) has a lot of overlap with augmented reality (AR). It is probably best to see them as part of a single spectrum between real-life and total virtual reality. In the future, VR will mesh with AR and you'll be able to "fade-in" some real-life reality into your virtual reality. Probably the main difference is that with virtual reality you have to stay put (walk, run, jump and rotate in place) because what you see doesn't represents the real world, so you'll quickly get painful, and potentially dangerous, feedback if you try to move around.
The Technology Behind Augmented Reality
AR is a combination of hardware and software. As far as hardware goes the set of technologies involve sensors of different types, innovative displays and massive processing power. The sensors are needed to locate the user in space, head position and often hand position. The displays typically come either as a head mounted display, glasses, contact lenses or even retinal virtual displays. There isn't yet a lot of work on full haptic interfaces.
Many sophisticated algorithms are used by AR systems including gaze tracking, image registration, object recognition, SLAM (simultaneous localization and mapping) and various mathematical methods for scene reconstruction.
Augmented Reality Applications
The applications of augmented reality are endless. Of course the real killer applications could be something nobody imagines right now. Some the obvious ones are designs in which designers can mix real objects with virtual designs and changes, education where the subjects of learning can be augmented, gaming where you can play in real locations, military when battlefield information can be displayed in real time for soldiers, information technology where augmented reality can take visualization to another level, tourism where information on the places you visit can be embedded in the environment as well as automatic translation of signs and menus.
Concerns About Augmented Reality
Some people look at AR as rose colored glasses, which it can definitely be. But, some serious concerns about privacy and safety have been raised. The Google glass project released in 2013 caused a lot of controversy and many organizations banned its usage due to privacy and/or security concerns. The ability of a Google glass user to unobtrusively record people and events was very concerning in some contexts. It was even considered illegal in some countries. Another big concern was safety, in particular when operating motor vehicles.
Developing Augmented Reality Applications Today
OK. You're intrigued. You want to get started today. Good news. There are several avenues open to you today. Microsoft HoloLens, arguably the most innovative product, has a whole site for developers. If you're fine with developing in the Windows environment, check it out here.
If you want to develop AR applications for today's smart phones, there are many toolkits and SDKs out there including the open source http://artoolkit.org/.
Augmented reality is a reality! The technology is there and improving. Big companies are pouring a lot of money into research and shipping products. The applications are mind-blowing. If you're looking into a cool and promising domain to dive into, you can't go wrong with augmented reality.