THE INTEGRATED SURVEY OF NARROW SPACES AND UNDERGROUND ARCHITECTURE: THE CASE STUDY OF CAMPANA CAVES BAS-RELIEFS

Italian Cultural Heritage is rich in fascinating Underground Heritage (UH) to be protected and preserved because of its fragility and historical importance. An accurate and high-resolution 3D model is essential to reach an appropriate level of knowledge to safeguard caves but there are several obstacles to face. Underground data acquisition and following elaborations are problematic due to environmental conditions such as lack of homogeneous light sources, highly absorbing and unstable surfaces, narrow spaces and complex geometry. For these reasons, the integration of different techniques is mandatory to achieve a valid final product that could be an important basis for consolidation, preservation and valorization of the UH. In this paper, an integrated survey method is tested for a realistic digital reconstruction of hypogeal spaces. In addition to outputs for experts of conservation, the creation of multimedia products for a wider audience of non-professionals users is investigated as a way to preserve UH from decay. Thanks to VR, visitors virtually walk through the underground galleries observing and interacting, making accessible also fragile environments with forbidden access due to preservation policies

DIGITAL TRANSITION STRATEGIES AND TRAINING PROGRAMS FOR DIGITAL CURATION OF MUSEUM

Small and medium-sized museums have been particularly impacted by the COVID-19 pandemic, as they often have limited resources and staff to manage the challenges posed by the pandemic. In order for them to survive during the pandemic but also embracing the extensive use of technology in our everyday lives, museums have to adapt to this new reality. The aim of the Museum-Next project is to provide small and medium-sized museums with a new generation of specialised EU professionals working in the Cultural Heritage sector, equipped with a recognised, cross-cutting and high-level digital skillset: the Digital Curators. In the digital age, museum digital curators play a critical role in preserving, organising, and presenting museum collections online. As part of the project, our research performed a desk analysis on the state of the art on museum digital transition strategies and museum digital curator training programs already implemented at EU scale in order to map good practices and tools already existing so as to highlight the current situation and the gaps that may appear in the topic

FROM TLS TO HBIM. HIGH QUALITY SEMANTICALLY-AWARE 3D MODELING OF COMPLEX ARCHITECTURE

In order to improve the framework for 3D modeling, a great challenge is to obtain the suitability of Building Information Model (BIM) platform for historical architecture. A specific challenge in HBIM is to guarantee appropriateness of geometrical accuracy. The present work demonstrates the feasibility of a whole HBIM approach for complex architectural shapes, starting from TLS point clouds. A novelty of our method is to work in a 3D environment throughout the process and to develop semantics during the construction phase. This last feature of HBIM was analyzed in the present work verifying the studied ontologies, enabling the data enrichment of the model with non-geometrical information, such as historical notes, decay or deformation evidence, decorative elements etc. The case study is the Church of Santa Maria at Portonovo, an abbey from the Romanesque period. Irregular or complex historical architecture, such as Romanesque, needs the construction of shared libraries starting from the survey of its already existing elements. This is another key aspect in delivering Building Information Modeling standards. In particular, we focus on the quality assessment of the obtained model, using an open-source sw and the point cloud as reference. The proposed work shows how it is possible to develop a high quality 3D model semantic-aware, capable of connecting geometrical-historical survey with descriptive thematic databases. In this way, a centralized HBIM will serve as comprehensive dataset of information about all disciplines, particularly for restoration and conservation. Moreover, the geometric accuracy will ensure also reliable visualization outputs

ANALYSIS, THEMATIC MAPS AND DATA MINING FROM POINT CLOUD TO ONTOLOGY FOR SOFTWARE DEVELOPMENT

The primary purpose of the survey for the restoration of Cultural Heritage is the interpretation of the state of building preservation. For this, the advantages of the remote sensing systems that generate dense point cloud (range-based or image-based) are not limited only to the acquired data. The paper shows that it is possible to extrapolate very useful information in diagnostics using spatial annotation, with the use of algorithms already implemented in open-source software. Generally, the drawing of degradation maps is the result of manual work, so dependent on the subjectivity of the operator. This paper describes a method of extraction and visualization of information, obtained by mathematical procedures, quantitative, repeatable and verifiable. The case study is a part of the east facade of the Eglise collégiale Saint-Maurice also called Notre Dame des Grâces, in Caromb, in southern France. The work was conducted on the matrix of information contained in the point cloud asci format. The first result is the extrapolation of new geometric descriptors. First, we create the digital maps with the calculated quantities. Subsequently, we have moved to semi-quantitative analyses that transform new data into useful information. We have written the algorithms for accurate selection, for the segmentation of point cloud, for automatic calculation of the real surface and the volume. Furthermore, we have created the graph of spatial distribution of the descriptors. This work shows that if we work during the data processing we can transform the point cloud into an enriched database: the use, the management and the data mining is easy, fast and effective for everyone involved in the restoration process

ANALYSIS, THEMATIC MAPS AND DATA MINING FROM POINT CLOUD TO ONTOLOGY FOR SOFTWARE DEVELOPMENT

The primary purpose of the survey for the restoration of Cultural Heritage is the interpretation of the state of building preservation. For this, the advantages of the remote sensing systems that generate dense point cloud (range-based or image-based) are not limited only to the acquired data. The paper shows that it is possible to extrapolate very useful information in diagnostics using spatial annotation, with the use of algorithms already implemented in open-source software. Generally, the drawing of degradation maps is the result of manual work, so dependent on the subjectivity of the operator. This paper describes a method of extraction and visualization of information, obtained by mathematical procedures, quantitative, repeatable and verifiable. The case study is a part of the east facade of the Eglise collégiale Saint-Maurice also called Notre Dame des Grâces, in Caromb, in southern France. The work was conducted on the matrix of information contained in the point cloud asci format. The first result is the extrapolation of new geometric descriptors. First, we create the digital maps with the calculated quantities. Subsequently, we have moved to semi-quantitative analyses that transform new data into useful information. We have written the algorithms for accurate selection, for the segmentation of point cloud, for automatic calculation of the real surface and the volume. Furthermore, we have created the graph of spatial distribution of the descriptors. This work shows that if we work during the data processing we can transform the point cloud into an enriched database: the use, the management and the data mining is easy, fast and effective for everyone involved in the restoration process

Colore, geometria e riflettanza. Uso integrato dei dati Lidar per il rilievo e la diagnostica: il caso studio di Villa Trissino

Le nuove tecnologie laser scanning “all in one” applicate al rilievo architettonico si stanno dimostrando efficaci, flessibili, economiche e speditive permettendo l’acquisizione, all’interno di prese omologhe, di differenti tipi di dati. La letteratura a riguardo è ampia e descrive dettagliatamente le potenzialità nel rilevamento morfologico, materico e anche colorimetrico dei manufatti. Le ormai note tecniche di mappatura delle immagini fotografiche alla nuvola di punti consentono di completare punto per punto il dato spaziale col dato colore (RGB), in fotografie HR. Di supporto alla buona lettura della superficie, l’operatore si serve del valore percentuale di riflettanza (R%), generando delle mappe graduate che consentono il riconoscimento visivo degli elementi scansionati. Ne consegue che il concetto di modello solido applicato alle più “recenti” nuvole di punti può aggiornarsi nel considerare il modello stesso come un vero e proprio sistema informativo del manufatto in cui i livelli di analisi si integrano restituendo nel contempo esiti morfologici, geometrici, colorimetrici e materici. Quello della riflettanza è, in questo senso, forse il dato meno indagato, almeno qualitativamente. L’intento di questa ricerca è di dimostrare come il dato di riflettanza da rilevamento scanner laser possa essere (in particolari condizioni) comparato a quello ottenibile da prove non distruttive comunemente applicate ai beni artistici, integrandone gli esiti con i dati qualitativamente rilevanti di carattere metrico, morfologico e geometrico restituiti dallo strumento laser. Il valore aggiunto, non trascurabile, è avere ampie portate dello strumento (fino a 300 metri), con notevoli potenzialità quindi nell’ispezione di superfici di difficile accesso. In letteratura si dimostra che le variabili maggiormente influenti su R% sono l’angolo di incidenza e l’indice di rifrazione dei due materiali attraversati, quest’ultimo determinato dalla microstruttura del materiale. Pur nella consapevolezza che nel nostro campo di applicazione entrano in gioco anche la distanza dall’oggetto e la scabrezza della superficie, è possibile ottenere valutazioni comparate dei dati che indirizzino le più opportune prove diagnostiche dirette. Le superfici indagate sono i prospetti intonacati di Villa Trissino a Cricoli, Vicenza, opera fondamentale nell’avvio del percorso architettonico di Andrea Palladio. E’ stata condotta un’analisi comparata relativa, valutando lo scarto dell’indice all’interno di aree omogenee e correlandolo agli stati di degrado superficiale valutati di caso in caso. Il nostro emettitore laser a impulsi (Laser C10 Leica) genera un fascio di colore verde (= 532 nm) nello spettro del visibile. Il valore di riflettanza acquisito non può essere, nella maggior parte dei casi, confrontato in termini assoluti, ma valutando e controllando le variabili ambientali è possibile ricavarne conclusioni in merito allo stato di degrado del materiale in esame. Dal confronto con la termografia è possibile validare tali risultati per la realizzazione di mappe tematiche di degrado. La loro applicazione permette di rintracciare distacchi di intonaco, aree a rischio per contenuti di umidità non visibili, dilavamento, salinità delle murature sottostanti etc. Le indagini visive finora utilizzate nella diagnosi dello stato di degrado superficiale possono ora servirsi di tali strumentazioni per una valutazione analitica dei meccanismi di degrado, con una metodologia di indagine speditiva e acquisibile nella fase di rilievo metrico

3D change detection for cultural heritage monitoring: Two case studies of underground sculptural reliefs

The preservation of underground cultural heritage is a challenging goal. Difficult acquisition conditions, the need for uniformity of temporal data and the speed at which surfaces change are some of the issues to consider. Also, quantifiable three-dimensional data are often unavailable when assessing changes on sculptural reliefs because traditional records are two-dimensional. In this paper, we present a workflow to easily detect and measure 3D superficial changes in sculptural reliefs using the deviation analysis technique. We compared multitemporal surveys, testing a quantitative, replicable, and verifiable procedure in two case studies: the reliefs of Pakal’s Tomb at Palenque, Mexico, and those of the Osimo Caves in Italy. Both are located underground and show similar superficial alterations such as material disaggregation, efflorescence, salt crusts, and biological colonization. The reliefs showed visible and quantifiable changes on the deviation maps. The procedure to detect changes can be implemented with models generated by structured light scanning as well as photogrammetry

INTEGRATED TECHNOLOGIES FOR SURVEYING ARTEFACTS DAMAGED BY EARTHQUAKES. APPLICATION OF ALL-IN-ONE LIDAR TECHNIQUES IN THE CITY OF L'AQUILA

The purpose of this work is to demonstrate how, in post-earthquake intervention scenarios, the latest "all-in-one" laser technologies employed beyond their usual applications and integrated in more traditional survey methods, can define a comprehensive and original approach method in response to surveying issues, safety of the artefacts, speed and low cost of surveys, quality of data and of the models provided for damage assessments and any required action. The case study of L'Aquila is therefore significant. The red area has essentially two types of buildings: monuments and historical buildings characterised by compact urban centres. Here we document the convent of the Blessed Antonia and the Antenucci Block, as case studies and synthesis of the two types and ideal laboratories to test the chosen method. In the first case, we document the project on a building that is yet to be secured and that therefore presents delicate issues in terms of survey speed and completeness, also in relation to the precious decorations that it holds. In the other case, we document the survey of the typical block in Aquila, already secured which, given the size and complexity, requires an integrated approach, more complex and more time-consuming of methods of analysis