# Projected Augmented Reality Intelligent Model of a City Area with Path Optimization
## 1 Introduction  
Augmented Reality (AR) and Virtual Reality (VR) technologies are increasingly popular, as the hardware and software evolve and make them accessible for a wide range of applications. They have been applied to different areas because of their potential to enhance user experiences while learning, training, simulating, playing games or other tasks. They are the two most popular sub-areas of the wider concept of Extended Reality (ER), which has been proposed as an umbrella term, encompassing both AR and VR, as comprehensively reviewed by [PERSON] in Reference [1]. In 1994, a taxonomy was proposed by [PERSON] and [PERSON] [2] for mixed reality. [PERSON] and [PERSON] hypothesize that no real boundaries exist between the virtual and real worlds. Rather, they argue that it is possible to move from one world to another across a continuum, called mixed reality. The continuum goes from the real world to Augmented Reality, passing by Augmented Virtuality and ending at a Virtual Environment. In the Virtual Environment, the user will be fully immersed in a digitally calculated world. Augmented reality is also described by [PERSON] in 1997 as a technology in which \"3D virtual objects are integrated into a 3D real environment in real time\" [3]. [PERSON], in 2011, follows a similar approach, in a context where augmented reality is described as \"the addition of a computer-assisted contextual layer of information over the real world,\" while being recognised as one key technology to become popular for museums in the mid term. [PERSON], in a book entitled \"Augmented Reality--Where We All Will Live\" [4], makes a thorough review of the current AR technology,applications and trends. The author projects that AR will be a market of $90 billion in 2020, becoming increasingly more important in human life in the coming years. VR for education and training has been studied since the 1980s and 1990s [5]. In this context, it provides a safe environment in which the learners and trainees can interact with virtual objects and scenarios, possibly making mistakes without being hurt or causing damage. [PERSON] et al. reviewed applications of AR and VR in manufacturing [6]. [PERSON] reviewed applications of VR in the industry of tourism [7]. For tourism, VR can provide experiences where the user is immersed in a virtual environment which mimics places and experiences, at a fraction of the cost and time required to visit the actual place. Several new applications have emerged in recent years. [PERSON] and [PERSON] propose a framework for successfully deploying AR in marketing campaigns, capturing consumers' attention and engagement [8]. [PERSON] et al. present an analysis of the impact of AR mobile applications developed for marketing purposes. The applications analysed are Ikea Planner--which allows the users to place virtual furniture in a physical room--and Tunnel--which projects song-related information to a user's environment. Based on surveys, they conclude the use of the applications has a positive impact on users' attitude towards the brands [9]. [PERSON] describes the use of VR for therapy, where patients benefit from VR experiences for pain control and phobia control [10]. Most of the technologies used for AR and VR rely on specific individual devices. Microsoft's HoloLens (More information about Hololens available at [[https://www.microsoft.com/en-us/hololens](https://www.microsoft.com/en-us/hololens)]([https://www.microsoft.com/en-us/hololens](https://www.microsoft.com/en-us/hololens)) (last checked 2019-07-06).) is a device which places virtual objects and information in the user's field of view, therefore creating an experience of augmented reality.Oculus Rift (More information about Oculus Rift available at [[https://www.oculus.com/](https://www.oculus.com/)]([https://www.oculus.com/](https://www.oculus.com/)) (last checked 2019-07-06)) is a VR headset that occupies all the user's field of view, so that the user will only see and interact with virtual objects shown in the headset.