**3. Materials and Methods**

#### *3.1. Mobile Augmented Reality (MAR) Setup*

The AR application presented in this paper was developed with the aim of bringing to life specific moments from Ovid's life. It was designed for the Lenovo Phab 2 Pro phablet (which incorporates the Google Tango technology). At the time of the research, this was the only Tango-enabled device available on the market. Phab 2 Pro used a Qualcomm Snapdragon 652 processor, 4 GB of RAM, and 64 GB storage. It used specialized Tango-related sensors—a fisheye camera that can handle the motion tracking, and an infrared depth sensor that used the "time-of-flight" principle to corroborate data with the video stream outputted by the camera [66]. Google Tango incorporates three core components:


The AR application that was developed by our team was called OvidAR and used motion tracking and area learning. It required a map in order to start the 3D scene. The workflow for using a Google Tango-enabled device is presented in Figure 2. The area learning application was a demo provided by Tango Project and can only be used to create new area descriptions. The OvidAR application started the 3D scene if there was a previously saved map and if it detected the key visual features that were saved in the area's description file.

**Figure 2.** Proposed augmented reality workflow using Project Tango.

Real-time tracking and localization ensures that the user is immersed in the scene. Various animations of the 3D versions of Ovid created a feeling of interaction. Another key element that enhances the experience is the sound, specifically the reverberation zones that distort the audio depending on the location of the audio listener in the reverb zone.

The developed application can run only on Tango-compatible devices. There were some devices that supported Google Tango, like Asus Zenfone AR, but now the project is closed. Google introduced a new AR platform, known as ARCore. Users can still develop AR application using Tango technology, but there are no other releases or provided support.
