Augmented reality (AR) refers to technologies that dynamically blend real-world environments and context-based digital information.
More formally, AR has been defined as a system that fulfills three characteristics (Azuma, 1997): First, it combines the real and virtual world.
Second, it allows real-time interaction. Third, it aligns real objects or places and digital information in 3D. In some professional contexts (e.g.,
military), AR technologies have been around for more than 50 years, but only the recent proliferation and consumerization of mobile
technologies (e.g., smartphones, tablets) made affordable AR systems available for the broad public. Today's mobile AR applications leverage
the built-in cameras, GPS sensors, and Internet access of mobile devices to overlay real-world environments with dynamic, context-based,
and interactive digital content.