Keywords

Short Intro

The AMOR project [1] was born with the aim of offering services in the areas of Safeguard and Fruition of Cultural Heritage. These services are about circular safeguard (Fig. 1) and fruition, fully responding to the strategies of MiC.

Fig. 1.
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Circular safeguard

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1 Introduction

The AMOR - Advanced Multimedia and Observation services for the Rome cultural heritage ecosystem - project, co-financed by the Italian Space Agency (ASI) and coordinated by the European Space Agency (ESA) and the Ministry of Culture (MiC), falls within the scope of the ESA 5G for L'ART (Business Applications program) call.

Project activities, lasting 24 months, are coordinated by NAIS Srl, leader of a group composed of public and private entities (ICR, CNR-IREA, CoopCulture, NITEL, ESRI Italy), each of them with extensive experience and expertise in the various aspects addressed in AMOR.

The project mission was conceived because of the more and more evident need to take technologies and digital tools available today, apply them systematically, and put them at the service of Public Bodies responsible for the conservation and enhancement of the Italian cultural heritage, as well as for stakeholders and private users interested in such sectors.

The monuments of Rome, application scenario of AMOR services, are the suggestive archaeological complex of the Baths of Caracalla and a southern stretch of the mighty Aurelian Walls (from Porta San Sebastiano to Porta Latina).

2 Safeguard: Needs, Technologies and Methodologies

Among the main needs of end users, which AMOR services aim to satisfy, there is undoubtedly that of a greater awareness of the conservation status of monuments, and the nature and severity of the main criticalities that impact them.

To meet these needs, thanks to satellites, AMOR makes use of technologies for the observation of the territory over a large area, and also offers a high detail of the surfaces (few cm) through the use of UAV (Unmanned Aerial Vehicle) systems. Then comes a sub-surface investigation of both soil and vertical structure, such as walls, through the use of GPR (Ground Penetrating Radar).

2.1 Remote Observation of Surface Degradation: Satellites and Drones

For the remote observation of damage and dangers of the territory, impacting on cultural heritage and the areas adjacent to them, as well as for the observation of their evolution over time, AMOR makes use of instruments such as satellites, equipped with multispectral sensors and SAR (Synthetic Aperture Radar) sensors, along with UAV systems, also equipped with appropriate sensors selected on the basis of the degradation phenomenon to be detected.

SAR sensors, through the use of the PS-InSAR (Permanent Scatterer - Interferometric Synthetic Aperture Radar) technique [2], are now widely recognized and used; they allow the extraction of information on the slow millimeter displacements of the ground, and that of the buildings placed above it, which otherwise are not detectable if not through the installation of dedicated sensors that, in any case, provides punctual information unlike the vast area coverage guaranteed by satellites. Therefore, periodic monitoring using this technique allows for an improvement in knowledge of the critical issues related to the instability of the ground, and the reflections that these may have on the monuments (see Fig. 2).

Fig. 2.
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PS-InSAR analysis on the historic center of Rome - GIS St'ART platform

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The multispectral sensors mounted on board satellites are, on the other hand, used in AMOR with two main purposes: a) analysis of the infesting vegetation on roofs or wall ridges of the monuments (1st level analysis); b) change detection, over a vast period of time, of a specific urban sector.

In the latter case, the use of commercial satellites with high spatial resolution (VHR) is essential for the identification and mapping of changes in the urban fabric, which cannot be observed otherwise. These have the function of extracting valuable information for the refinement of the calculation of the vulnerability of urban units and the associated risk (Risk Card - ICR/MiC).

In fact, Risk Map [4, 5] is now evolving testing an extension of the analysis of the conservation status from the single monument to the urban unit. AMOR project has a specific case study in the area nearby via della Lungara (Rome historical centre, in Trastevere zone).

However, for the purpose of further information or more precise observations that the satellite is unable to provide, the use of UAV systems refines and completes the range of services. Through these, in fact, it is possible to detect and map the damage that occurs on a specific monument, with a view to improving knowledge of the conservation status of a monument and also contributing to the calculation of the vulnerabilities of individual monuments.

2.2 The GPR System

The georadar - or GPR - is another technological tool used for safeguard purposes in AMOR.

It is a radar system designed for carrying out sub-surface surveys, increasingly used in the Cultural Heritage sector [3]. By exploiting the ability of microwaves to penetrate non-metallic materials and sophisticated data processing procedures, often optimized for the specific application of interest, the georadar provides high resolution images of the investigated region in a non-invasive way. These images make it possible to locate buried objects, whose shape and dimensions can be reconstructed, and to characterize degradation phenomena that can damage the structure under examination.

In AMOR, GPR is used both to carry out surveys of the subsoil - aimed at increasing knowledge of the site, thanks to the identification of underground objects of which memory has been lost, for example walkways and/or underground cisterns, as in the case of the archaeological complex of the Baths of Caracalla - and to carry out structural investigations aimed at characterizing the cracks, as in the case of the Aurelian Walls.

The AMOR GPR system is a highly flexible system, as it can be equipped with antennas operating at different frequencies (from a few tens of MHz to a few GHz), thus allowing to reach different depths of penetration and to obtain images at different spatial resolutions, in order to satisfy the requirements dictated by the purpose of the survey requested by the user. The acquired data are processed using procedures developed by CNR - IREA researchers. These procedures involve both filtering algorithms that aim to emphasize the useful signal, meaning the signal due to objects of interest, and tomographic reconstruction approaches which, by solving an inverse problem of electromagnetic diffusion, produce focused images of the identified objects, making their accurate geometric characterization possible. These images therefore provide useful information for the safeguarding and optimized maintenance of the site, and can be used to make (not otherwise visible) artifacts available to visitors.

At the present stage of the project, two GPR measurement campaigns have been carried out, one at the archaeological complex of the Baths of Caracalla and the other at a portion not accessible to visitors of the southern part of the Aurelian Walls, affected by a non-negligible phenomenon of fracturing.

Figure 3 shows the measurement campaign carried out at the Baths of Caracalla, where attention was focused on the area of ​​gardens and avenues. A preliminary result, obtained by applying only the filtering procedures to data acquired along one of the avenues, is shown. Several sub-superficial anomalies can be noted: the first, on the left, located at a depth of about 1.2 m – and the others, at about 2 m. The anomalies could be associated with cisterns and/or tunnels. Further investigations are underway in order to arrive at their correct interpretation.

Fig. 3.
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Prospecting with GPR at the baths of Caracalla

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3 Fruition

As mentioned in the introduction, AMOR also aims to develop services dedicated to fruition. In fact, in a historical period characterized by a pandemic still in progress, the possibility of giving users multimedia contents certified and approved by the authorities directly responsible for the monuments, undoubtedly gives added value to the experience of a cultural tourist.

The service proposed by AMOR therefore provides for the development of a mobile app that offers certified information content and emotionally engaging experiences (e.g. Mixed Reality (MR)), for a more in-depth and immediate knowledge of cultural heritage.

3.1 New Fruition Solutions

Today, technological innovation in the digital field allows the creation and development of new tools for the enhancement of cultural heritage, capable of offering the public contents with previously unimaginable communication potential and, at the same time, of collecting useful data for the protection of the interested sites.

The Mobile App designed and developed for the AMOR project is able to offer an innovative form of fruition, which combines advanced multimedia content and simplification of use through itineraries and georeferencing. The tool is designed to be used in total autonomy by visitors from all over the world and enjoyed in different languages.

The App provides a catalog of contents created to enjoy urban tourist itineraries in different cultural places, such as museums, archaeological areas, monuments. A map of the city indicates the user his position (in case of active GNSS and in full compliance with current privacy regulations) allowing him to orient himself and decide which itinerary to follow, or which site to visit and - if interested - the user can also download and enjoy the various contents available directly on the device.

Today, with a smartphone, anyone can reach an unimaginable amount of information in a short time. But what contents are actually reliable? The app of the AMOR project, developed with cultural institutions, allows the user to access scientifically approved and quality content, together with the proposal of experiences not otherwise accessible online. The multimedia contents, created by storytelling professionals, guide the user throughout the tour, focusing his attention on the most significant details for a correct understanding of the monument. Satellite and graphic maps, audio commentary, image galleries, texts, virtual reconstructions, elements of Mixed Reality, are from time to time combined together to create an emotionally engaging visiting experience. In particular, in AMOR the use of Mixed Reality (MR) will allow users to view 3D models of the Baths of Caracalla complex, facilitated by 5G and 4G connections.

The informative and educational purposes of the application are closely linked to those of the protection and enhancement of the sites visited, by collecting useful data about visitor flows (see next paragraph) (Fig. 4).

Fig. 4.
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Mobile APP for viewing 3D models in MR at Baths of Caracalla

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3.2 Circular Fruition

According to what has just been described, what contributes to making AMOR innovative is precisely the circularity of the data collected through different sources, a circularity that leads to the generation of further information material that flows into the safeguard sector, feeding the knowledge of “indirect vulnerability” of the property, also impacted by anthropogenic causes.

The anonymous collection of visitor positioning data will allow for an analysis of flows (data analytics) relating to the places they visit.

This analysis process is integrated with a geofencing activity, which consists in identifying crossing areas of which the positioning data are recorded, giving additional information.

In addition to data collected by the mobile app, the analysis of flows will also be fed by data available on the market relating to the gravitation on telephone cells of the various mobile devices, the so-called gravitational databases, or data made available by some telephone operators or companies which enrich the databases after some analysis processes. This latter product was taken into consideration in AMOR to enrich the project (and the service in the future) with a component of historical data analysis, useful for building behavior patterns over longer times and which also takes into consideration visitors not downloading or installing the app. In particular, the GeoMobile DB product was used for the project, as it offers data on a quarterly basis, referring to the census sections from which it is possible to obtain information on time bands of influx, age, nationality (if Italian or foreign), type of user (whether business or private).

For the analysis and visualization of this data, the project will use the ArcGIS Enterprise platform, containing the modules defined as Geotools that have been developed. Within the platform, used for the definition and management of the geofencing areas and for the analysis and visualization of data, applications will be developed for the visualization on the map, and also diagrams with the analysis results, through dashboards that will allow the user manager of the area to have a synoptic picture about the trend of the visitors’ flow.

The assessments that may be made by the area manager will be useful for making decisions in order, for example, to enhance less visited places, affix information/promotion signs, place information points, reorganize visitor routes and so on.

3.3 The Importance of 5G

5G supports the AMOR project with a view to a more fluid mobile fruition.

The fifth generation of mobile network - namely 5G - brings with it important advances and revolutions in the telecommunications sector. 5G, in addition to offering a higher transmission speed and lower latency compared to the previous generation 4G/LTE (and other technological improvements), offers significant innovations from the infrastructural, functional and services point of view.

In fact, 5G includes innovative design paradigms such as Software Defined Networking (SDN) and virtualization of network functions (NFV). These technologies allow the creation of a virtualized network infrastructure that is completely computerized as regards the functionality and management of the network itself [6]. All this makes the 5G ecosystem flexible and adaptable to the characteristics of the service, allowing the design of independent portions of the network, called “slices” [7]. The result is being able to provide advanced services that go beyond voice, message and data services offered right now by mobile networks, which meet the needs of new virtual operators (called “verticals”) in the automotive sectors (e.g. autonomous driving), smart cities (e.g. sensor networks), eHealth (e.g. telemedicine), media (e.g. augmented reality), Industry 4.0, etc [8].

In this context, the use of the 3D multimedia contents offered in itinere during city tours, foreseen by the AMOR project, can enjoy the great potential offered by 5G networks, allowing to define a new “Vertical” in the culture/infotainment sector. Specifically, the full availability of 5G will allow the application to interact directly with a “slice” of the network, making use of the processing of large amounts of data in the network itself, at low latency, offering a user experience that is even superior to what is possible today.

4 Conclusions

The complexity of the AMOR system sees its own simplification in the way it is made available to end users.

Access to information relating to traditional and “collateral” safeguarding (from the mobile app) takes place through a single data consultation point: the St’ART® platform [9], which provides all the tools for reading the acquired data (satellite, UAV and GPR), facilitating the user in the subsequent actions to be taken, where necessary, and supporting him through a specially designed and calibrated workflow.

A simplification in the context of fruition is also implied for the end user, in this case the cultural visitor. The possibility of consulting official multimedia data, as well as the availability of innovative solutions (Mixed Reality) “within reach of a smartphone” and in full compliance with the anti-Covid-19 regulations, offers quality fruition that is aimed at everyone; just think of the current reticence in wearing a 3D viewer, or handling a device used by a third party.

The products derived from these services, once put into the system, will flow into what can be characterized as the Site Knowledge Hub, which over time, through participation in other projects that will see these same sites as a scenario for further activities, will be enriched and become a point of collection, correlation and consultation of information (for use and safeguarding).

Therefore, the preventive approach proposed by AMOR, which aims to trigger a reduction in costs for the aspects related to safeguarding (costs no longer oriented to the onerous emergency, but to ordinary maintenance) and an “enlarged” fruition, are designed to trigger a virtuous circle for what is called circular safeguarding.