High scale 3D modelling and orthophoto of curved masonries for a multipurpose representation, analysis and assessment

It is important nowadays to underline some relevant topics concerning the effective contribution of 3D high detailed products derived from innovation and integration of Geomatics technologies, allowing a remarkable development in descriptive metric capabilities, supporting and improving the material recording, representation, analysis and characterization about alteration of the constructive systems. Considering the relevance of the complex interdisciplinary research of these issues that move around the Cultural Heritage safeguard and due to its extreme vulnerability, these models must give a response to different problems. Primarily they has to provide complete models on which to pursue accurate morpho-dimensional documentation, and to base structural assessment, decay investigations, and consequently to underpin restoration practices and support operational workflow in CH assets monitoring. Some peculiarities of new methods for semi-automatic processing algorithms are thus evidenced, advantaging their proficiency to behave as tools for a more sustainable approach in the general process of preservation and protection. Specifically about the ancient masonries documentation, the chance of using digital products derived from very high scale models, as the detailed orthoimages projection and surfaces development offers many opportunities. Here, a late-medieval stratified dovecote tower in Verolengo (TO) with a particular trunk-conical shape had been analysed in order to reconstruct an identity and a historical and architectural framework, de facto not recognized yet. A 3D reconstruction by dense matching techniques will be presented, in the complex context that are the vertical high buildings, presenting one of the highest level of vulnerability. The importance of the 3D model availability, closely connected to dense radiometric information, has been particularly expressed in two main direction for the diagnosis both of volumetric structure assessment and the material characterization of the mixed masonries walls

A COMPARISON AMONG DIFFERENT OPTIMIZATION LEVELS IN 3D MULTI-SENSOR MODELS. A TEST CASE IN EMERGENCY CONTEXT: 2016 ITALIAN EARTHQUAKE

In sudden emergency contexts that affect urban centres and built heritage, the latest Geomatics technique solutions must enable the demands of damage documentation, risk assessment, management and data sharing as efficiently as possible, in relation to the danger condition, to the accessibility constraints of areas and to the tight deadlines needs. In recent times, Unmanned Vehicle System (UAV) equipped with cameras are more and more involved in aerial survey and reconnaissance missions, and they are behaving in a very cost-effective way in the direction of 3D documentation and preliminary damage assessment. More and more UAV equipment with low-cost sensors must become, in the future, suitable in every situation of documentation, but above all in damages and uncertainty frameworks. Rapidity in acquisition times and low-cost sensors are challenging marks, and they could be taken into consideration maybe with time spending processing. The paper will analyze and try to classify the information content in 3D aerial and terrestrial models and the importance of metric and non-metric withdrawable information that should be suitable for further uses, as the structural analysis one. The test area is an experience of Team Direct from Politecnico di Torino in centre Italy, where a strong earthquake occurred in August 2016. This study is carried out on a stand-alone damaged building in Pescara del Tronto (AP), with a multi-sensor 3D survey. The aim is to evaluate the contribution of terrestrial and aerial quick documentation by a SLAM based LiDAR and a camera equipped multirotor UAV, for a first reconnaissance inspection and modelling in terms of level of details, metric and non-metric information

OBLIQUE IMAGES AND DIRECT PHOTOGRAMMETRY WITH A FIXED WING PLATFORM: FIRST TEST AND RESULTS IN HIERAPOLIS OF PHRYGIA (TK)

Abstract. The complex archaeological site documentation benefits for a long time now from the aerial point of view and remote sensing methods. Moreover, the recent research on UAV photogrammetry platform equipment and flight planning actively contribute in this sense for a scaling improvement and cost-benefits balance. Frequently, the experiences on articulated topographic profiles in archaeological excavations require not only a multi-sensor approach but also and above all a multiscale one. According to this line, in a general time-cost ration framework, the geometric content of the generated DSMs should be complete of nadir and oblique point of view for the accurate 3D reconstruction of both upstanding buildings and excavations. In the same way, also the radiometric content closely depends on sensor payload quality and is strictly affected by excavation site condition, related to the site material and light. In this research, carried out in the impressive archaeological site of the ancient city of Hierapolis in Phrygia (Turkey) in the autumn 2019 campaign, the main goal was to evaluate and validate the overall performance of a novel UAV fix-wing ultralight platform with onboard GNSS receiver for RTK/PPK processing of cameras positioning and with the possibility of oblique images capturing. The expected contribute in terms of the acquisition, processing time, radiometric enhancement and geometry 3D reconstruction will be explored with preliminary test and outcomes, and with the results of the high-scale DSM and orthoimage generation of the complete Hierapolis site

Integrated HBIM-GIS Models for Multi-Scale Seismic Vulnerability Assessment of Historical Buildings

The complexity of historical urban centres progressively needs a strategic improvement in methods and the scale of knowledge concerning the vulnerability aspect of seismic risk. A geographical multi-scale point of view is increasingly preferred in the scientific literature and in Italian regulation policies, that considers systemic behaviors of damage and vulnerability assessment from an urban perspective according to the scale of the data, rather than single building damage analysis. In this sense, a geospatial data sciences approach can contribute towards generating, integrating, and making virtuous relations between urban databases and emergency-related data, in order to constitute a multi-scale 3D database supporting strategies for conservation and risk assessment scenarios. The proposed approach developed a vulnerability-oriented GIS/HBIM integration in an urban 3D geodatabase, based on multi-scale data derived from urban cartography and emergency mapping 3D data. Integrated geometric and semantic information related to historical masonry buildings (specifically the churches) and structural data about architectural elements and damage were integrated in the approach. This contribution aimed to answer the research question supporting levels of knowledge required by directives and vulnerability assessment studies, both about the generative workflow phase, the role of HBIM models in GIS environments and toward user-oriented webGIS solutions for sharing and public use fruition, exploiting the database for expert operators involved in heritage preservation

Image-based models using crowdsourcing strategies

This paper aims to highlight the effectiveness of the collaboration between the modelling techniques that exploit the stereoscopic images of objects and the ability of the present-day technologies to generate images, both found in the web and gathered by other crowdsourcing techniques. Since nowadays the generation of models from images is a major low-cost resource, the whole strategy is aimed at obtaining benefits in the context of the documentation of Cultural Heritage (CH). Assuming that the documentation of CH is the basis of the protection and the conservation policies, the chances of finding images and using them to create 3D models is particularly effective when the assets in question are at risk in danger zones (wars or areas subject to natural disasters) or in areas that, for various reasons, are difficult to access. To demonstrate the advantage of using low-cost methods for the generation of 3D models of documentation with strategies that fall within the sphere of crowdsourcing, the case of the Vank cathedral modelling is presented. The Vank Cathedral in Isfahan in Iran is a building of the Safavid epoch (cent. XVII–XVIII) completely frescoed in the internal surfaces, where the architecture and especially the architectural decoration reach their peak. The experimental section of the paper also explores some aspects of usability of the digital output from the image-based modelling methods. The availability of orthophotos allows and facilitates the iconographic reading of the frescoes, adding to the radiometric data, there is the metric potentiality of reading the proportions and the compositions of the organisation of the frescoes. Furthermore, simplified and suitably schematised models can be even printed and can be used in a didactic environment, such as the knowledge dissemination intended by the museums and other cultural institutions

Challenging multi-sensor data models and use of 360 images. The Twelve Months Fountain of Valentino park in Turin

The cultural heritage and the ways in which it is today studied and analysed as well as disseminated and enhanced for the purposes of conservation, requires high attention in the choice of 3D survey and modelling methods. This manuscript investigates the possible integrations and fusion of methods and data, among the vast availability of image and range based systems, especially in the sphere of low cost techniques, which in the context of heritage documentation makes the whole and complex process of conservation more sustainable. The investigation is carried out on a historical fountain that includes a quantity of cultural values and the need to document its context: its location in the historical Valentino of Turin park, its architectural values and the geometry of the complex typically related to the tastes of the late XIX century that consist in the extreme refinement of the statuary complexes and the underground portion with the technological equipment for the activation of the water games. Basically, it will be possible to appreciate solved issues and permanent criticalities derived from the integration of close range and UAV photogrammetry techniques in addition to the LiDAR survey, both classic from a fixed position, and in the portable scanner mode, based on SLAM technology

Fusion of 3D models derived from TLS and image-based techniques for CH enhanced documentation

Recognizing the various advantages offered by 3D new metric survey technologies in the Cultural Heritage documentation phase, this paper presents some tests of 3D model generation, using different methods, and their possible fusion. With the aim to define potentialities and problems deriving from integration or fusion of metric data acquired with different survey techniques, the elected test case is an outstanding Cultural Heritage item, presenting both widespread and specific complexities connected to the conservation of historical buildings. The site is the Staffarda Abbey, the most relevant evidence of medieval architecture in Piedmont. This application faced one of the most topical architectural issues consisting in the opportunity to study and analyze an object as a whole, from twice location of acquisition sensors, both the terrestrial and the aerial one. In particular, the work consists in the evaluation of chances deriving from a simple union or from the fusion of different 3D cloudmodels of the abbey, achieved by multi-sensor techniques. The aerial survey is based on a photogrammetric RPAS (Remotely piloted aircraft system) flight while the terrestrial acquisition have been fulfilled by laser scanning survey. Both techniques allowed to extract and process different point clouds and to generate consequent 3D continuous models which are characterized by different scale, that is to say different resolutions and diverse contents of details and precisions. Starting from these models, the proposed process, applied to a sample area of the building, aimed to test the generation of a unique 3Dmodel thorough a fusion of different sensor point clouds. Surely, the describing potential and the metric and thematic gains feasible by the final model exceeded those offered by the two detached models

ASSESSING TERRESTRIAL MMS 3D DATA FOR OUTDOOR MULTI-SCALE MODELLING

Mobile Mapping Systems (MMS) have recently benefited from the development of many fusion-based technologies with countless systems development based on cars, drones, trolley, wearable or portable mapping system. The scale of applicating range from the urban to the architectural scale. Recent solution are also based on visual or Lidar SLAM (Simultaneous Localization and Mapping), which substantially takes advantage of environmental features and techniques of continuous co-registration of the clouds, also in case of absence on GNSS positioning measurement. FARO Technology has recently developed the Swift, a fusion-based hybrid solution that integrates the sensors for 3D mapping in a trolley system configuration and recently, an external camera Panocam Theta Z1 is equipping the system enabling the possibility to associate radiometry to the acquired data. The working principle is the exploitation of a system of static and mobile configuration, using the so-called “anchor scans” co-registration as an hybrid intermediate solution between a typical static scan and a profilometers-based MMS point cloud. The co-registered clouds therefore yield a trajectory mode such as SLAM but benefit from the comparable range and density characteristics, according to user-customized settings, of static scans, with a duration of a few seconds per scan and a few minutes overall. In the present research the Swift System is tested in two different context and the assessment are conducted aimed at satisfying both the urban and the architectural scale instances in the direction of improving further evaluations

MINOR HISTORICAL CENTRES ONTOLOGY ENRICHMENT AND POPULATION: AN HAMLET CASE STUDY

The main topic of this work focuses on the semantic, historical and spatial documentation of Minor Historical Centres (MHC) with a focus on (semi-abandoned alpine) hamlets. The key point is the possibility to standardise spatial information in the domain of MHC and their related cultural, architectural, built and landscape heritage. This work analyses the notions of historical centre and ancient area, which took different meanings and evolved over the centuries. MHC are historical part of cities, villages and hamlets (urban, rural, minor or abandoned) with cultural, social and economic values. Thus, MHC need to be preserved, documented and safeguarded. The spatial and semantic documentation is a fundamental tool for increasing their knowledge. In these places, many actors and stakeholders are involved in different activities, and for this reason, they need to share common knowledge and use a unique language. In this regard, spatial ontology is of relevant interest and usability. Ontologies are conceptual structures that formalise specific knowledge and create a unique and standard thesaurus that ensures semantic interoperability. This paper is part of a PhD research targeted at developing an ontology containing helpful information to manage, share and collect data on MHC due to the lack of an interoperable structure to formalise such knowledge. The main aim is to populate and enrich the already developed ontological structure with data of a mountain semi-abandoned hamlet: Pomieri. The methodological workflow is validated, enriching and populating the ontology, adding classes and instances with information and unstructured data of a real data case study

Le scuole come infrastruttura territoriale

Il progetto Re-school nasce dalla collaborazione tra Fondazione Agnelli e il Future Urban Legacy Lab del Politecnico di Torino con un obiettivo preciso: offrire strumenti per la rigenerazione del patrimonio edilizio della scuola italiana affrontando i temi della sicurezza, dell’ambiente e dell’innovazione didattica. I circa 40.000 edifici che costituiscono l’infrastruttura scolastica italiana sono un’eredità stratificata e capillarmente diffusa sul territorio nazionale, che richiede un ripensamento anche alla luce dei cambiamenti sociali, demografici e pedagogici degli ultimi decenni. In questa pubblicazione vengono riassunti i primi passi del gruppo di ricerca e si propone un metodo di lavoro per esplorare il potenziale di trasformazione del patrimonio dell’edilizia scolastica in Italia. Il quinto capitolo si concentra sulla scala territoriale: misurazioni a scala regionale attraverso il caso studio piemontese permettono di contestualizzare e descrivere, tramite proiezioni e indicatori sintetici, le potenzialità degli edifici in relazione alle geografie di cui fanno parte