1,721,032 research outputs found
Restitución de datos láser escáner para el análisis del deterioro de bóvedas de ladrillo
No full textThe research, based on a real case, analyses the subsidence of the brick vaults. The goal is to identify a method of plotting data capable of detecting the critical zones of the vault, subject to further and detailed investigation.
In order to avoid a preliminary investigation of the vault with moderate vibration, it will be illustrated the possibility to implement a laser-scanner to code a procedure capable of detecting areas potentially damaged.
Through the transformation of point clouds in CAD data, it has been possible a further analysis of critical areas of the vault soffit down to the last centimetre. Drawing the deformations with different colours, based on the intensity of the subsidence, it has been possible to obtain a new representation, which clearly displays the critical areas. The results will be compared through the use, for example, of endoscope, to validate the method, and the representation and the use of the laser-scanner in the analysis of sagging of the brick vaults.
In conclusion, it will be illustrated the use of Rhinoceros for future applications: the 3D modelling will be used for a more specific analysis of the curvature of the vault
Un corretto approccio alle tecniche di fotogrammetria low-cost: il caso di 123D Catch
No full textL’articolo si focalizza sulla possibilità di realizzare ricostruzioni tridimensionali del patrimonio architettonico, implementando un’applicazione gratuita della Autodesk che permette di trasformare le prese fotografiche in vere e proprie scene 3D. Il funzionamento del software si basa sull’automatizzazione di un processo di reverse modelling, così, assumendo sempre validi i principi della fotogrammetria, è possibile stimare e conoscere la posizione nello spazio di ogni punto fotografato (ovviamente, purché collimabile in almeno tre prese). In particolare, le macchinose operazioni di riconoscimento dei punti omologhi avverranno per mezzo di un algoritmo di cloud computing, non richiedendo quindi, potenti calcolatori e limitando, di fatto, l’intervento del restitutore in questa fase. Le prese fotografiche impiegate per le elaborazioni grafiche che illustrano il contributo provengono da remoto, ovvero sono state collezionate in rete, acquisendole da fotografi e/o turisti anonimi, rintracciate e recuperate attraverso siti web di condivisione, per dimostrare così la possibilità di ottenere una foto-ricostruzione, sempre da remoto, di un’architettura nella sua geometria, texture ed colore. Infatti, la finalità di questo studio è anche quella di rendere disponibile, a un pubblico sempre più vasto, eventualmente anche privo di conoscenze specialistiche, informazioni valide e necessarie per tutelare architetture di interesse storico-artistico, preservandole dal possibile oblio, e favorirne la conoscenza attraverso l’utilizzo di queste nuove applicazioni per il rilievo dell’architettura. Sulla base del caso studio, quindi, si dimostrano le potenzialità ed anche gli eventuali limiti (valutando l’accuratezza del risultato finale) di queste nuove tecniche fotogrammetriche – semplici e automatiche – che sulla base di prese fotografiche dello stato attuale (o anche del passato, come nel caso di edifici ormai distrutti) permettono di coadiuvare le operazioni di recupero, anche solo virtuale, e la documentazione e valorizzazione del patrimonio architettonico, riportando alla luce tracce oramai perdute
Optimization of texture mapping process in the Reality-Based Modeling application
No full textClose-range photogrammetric survey supported by computer vision algorithms is used in many sector of research: Cultural Heritage is the field where there are more of its applications in. One of the key factor is represented by the hoped correspondence between a 3D geometric mesh and its high-definition texture; as an effect photogrammetry is a privileged tool for analysis of the degradation of surfaces also, for which the desired precision and accuracy is a must, but not only. During surveys on digital application in Cultural Heritage open issues due to integration and interoperability among different technologies are growing; this obliges us to consider different ad various pipelines looking for the most productive. This paper presents studies regarding a method to integrate the classic pipeline of the Image-Base Modelling with specific steps for the creation of a high detailed texture that is fused with normal maps in order to reach a higher geometric definition
Two methodologies for the virtual reconstruction of the architectural remains of a Late Roman archaeological site based on the 3D point cloud
Full text linkThis paper presents and discusses two approaches to the virtual reconstructions of the architectural remains of the Late Roman site of Umm-al Dabadib, at the outskirts of the Kharga Oasis (Egypt's Western Desert). The dense settlement is clustered around a central building resembling a fortlet. The primary construction material was mudbrick, completed by a few stone elements. Elliptical pitched-brick barrel vaults covered the small rooms that compose the various buildings. The unit of measurement used in the planning and building was the ancient Egyptian (reformed) cubit. The first method adopted to study these remains consists of direct 3D modelling on the photogrammetric point cloud using the parametric approach of the BIM software Autodesk Revit. This process allowed the complete reconstruction of all levels of the well-preserved fort in the settlement center. The second method tested, on the domestic unit in the northwest corner of the settlement, involved 3D modelling of hypothetical original form starting from 2D technical drawings elaborated from the photogrammetric point cloud in its current state and its hypothetical original form. These drawings were used as a reference to model the domestic unit in Rhinoceros software, which is more suitable to model complex shapes, such as typical living room of the local domestic units, covered by two intersecting barrel vaults of different sizes. The complex morphology of the biaxial vaulted system would have been difficult to model with a more rigid software such as Revit. Instead, Rhinoceros allowed recreating the biaxial vault using tools to extrude profiles, subtract and add simpler shapes. The photogrammetric model was used to adapt the reconstruction to accurate measurements
- …
