# Projected Augmented Reality Intelligent Model of a City Area with Path Optimization
## 1 Introduction
Other devices include simple enclosures for smartphones, where the smartphone provides the images for the user through a system of stereoscopic lenses. Those devices provide an impressive experience, in an immersive environment, where the user easily feels like they are living in the virtual or augmented world and detached from the real world. On the other hand, they have various ergonomic disadvantages such as limiting the user's field of vision and eye accommodation problems resulting from incorrect focusing distances. The fact that the user feels totally detached from the real world may also pose some dangers, especially for prolonged usage [11; 12; 13]. Projected Augmented Reality Models (PARM) work by diffusing the computer images directly onto a three-dimensional physical construction, which has the same shape as the projected model [14]. That is a specific branch of augmented reality that counters most of the ergonomic and health problems of conventional devices. It is also called Projection Augmented Reality, as well as Spatially Augmented Reality [15]. PARM also has disadvantages when compared to traditional Augmented Reality and Virtual Reality models. It requires a physical model which has a cost of production and requires time to produce and update. Notably, the experience of PARM is not as immersing as in VR or AR, but that is possibly why it does not cause sickness as the AR and VR experiences cause. Moreover, in PARM one simple setup can be experienced by many people at the same time. In AR and VR systems requiring headsets and special apparatus, the hardware is often for individual use, used by just one person at a time. The PARM experience, in the context of [PERSON]'s view of the mixed reality continuum, will lie closer to the Real Environment than the more popular AR and VR models. The idea of PARM for city modelling appeared more than twenty years ago. [PERSON] et al. proposed a model where small prototype buildings are augmented with projected imagery, using a number of different projectors [16]. In 2017, [PERSON] and [PERSON] proposed a PARM model to be used in architectural design [17]. The system works by projecting images over a flat surface where small white models of the buildings are manually placed. Users are able to observe the model and even, in some cases, interact with it. The present paper describes an application of Artificial Intelligence (AI) algorithms, namely a Genetic Algorithm (GA) and a search algorithm (A*), in order to solve the Traveling Salesman Problem (TSP) in a PARM. The PARM experience is achieved using a video projector over a 3D model of a portion of the city of Coimbra, Portugal. Geographical information to create the physical model was retrieved from OpenStreetMap (OpenStreetMap is available at [[https://www.openstreetmap.org](https://www.openstreetmap.org)]([https://www.openstreetmap.org](https://www.openstreetmap.org)) (last checked 2019-04-26)) (OSM). OSM data was then imported in Blender (Blender Open 3D Creation Software is available at [[https://www.blender.org/](https://www.blender.org/)]([https://www.blender.org/](https://www.blender.org/)) (last checked 2019-04-26)), where further layers of information were added and the final 3D model was designed. The 3D model of the area was then built using wood pieces cut in a precision laser cutter, before being finished and painted white. It was also imported for Unity (Unity 3D development platform is available at [[https://unity.com/](https://unity.com/)]([https://unity.com/](https://unity.com/)) (last checked 2019-04-26)) game engine, where the AI algorithms were implemented, as well as the user interface for control using a smart phone, tablet or computer. The application was named Projected Augmented Reality Intelligent Model Control (PARIMC). Section 2 describes the architecture of the system. Section 3 describes the experiments performed to optimize the model and the results obtained. Section 5 draws some conclusions and perspectives of future developments.