**3. Augmented reality**

Current virtual reality technologies are based on ideas constructed and reported from the 1960s and possibly earlier, such as the iconic Ivan Sutherland who in 1968 created the first head-mounted display that rendered simple wireframe models for pose change of the viewer [12]. It was through the foundations of this invention and with technological innovations and other evolutions that we now call Virtual Reality (VR), Augmented Reality (AR) and Mixed Reality (MR) (**Figure 3**) [13].

With the concept of VR conceived more than fifty years ago, when the first immersive human-computer interaction (HCI) mock-up called "Human-Machine Graphic Communication System" was invented [12] the formal term of VR was placed in 1989 on the RV continuum based on Milgram's taxonomy where VR represents the creation of a virtual reality or. environment in which the user can enter this scene with the feeling of being in the "real" world, with limited level of "realism" such as visual and sound effects [14].

According to this definition, AR is an environment where additional data generated by the computer is fed into the user's view of a real scene [15]. With AR, users can access, visualize and interact with complex information in the context of the real environment, or in other words, computer-generated elements are added to the seen reality. Since the entry requirements for a AR capable device are relatively low, many of today's smart devices (phones, tablets) are suitable for AR use.

With the growth and maturation of technologies in AR, applications end up becoming more viable and popular for both the education, design, manufacturing, construction and entertainment sectors, becoming potential in helping to improve existing technologies and, with that, can promote a better quality of life mainly for people with physical and/or mobility limitations.

**Figure 3.** *Reality-Virtuality continuum [13].*
