1,721,070 research outputs found
Spatio-temporal analysis of georeferenced time-series applied to structural monitoring
Full text linkSpatio-temporal (S-T) analysis is not typical in structural monitoring applications of buildings and infrastructure. However, monitoring always includes the temporal component, and observations are often captured in specific locations. In other words, a monitoring dataset could also be considered a spatio-temporal archive, notwithstanding that not all monitoring applications can benefit from S-T processing methods. The paper discusses spatio-temporal analysis using the structural monitoring dataset of the Cathedral of Milan, which has an archive of vertical settlements collected from more than 50 years of measurements. The proposed methods can be adapted and extended for other structural monitoring applications, including single buildings, infrastructure, and the environmental level. The cases of pure temporal (T) and spatial (S) analyses are also discussed, comparing the different approaches, illustrating the pros and cons, and describing the opportunities of the S-T combined workflow. The paper specifically focuses on different typologies of S-T processing: data visualization and exploration techniques, clustering, change detection, prediction, and forecasting. The proposed algorithms were all implemented within the R open-source programming language. They can be replicated (and adapted) for other structural monitoring datasets featuring spatio-temporal correlation
Drone Mapping in Inner Areas: Strengths and Limitations
Full text linkPrecise and comprehensive metric documentation of inner areas presents unique challenges due to their inherent characteristics and variability. While achieving a complete digital record demands the use of various instruments and tools, not limited solely to on-site data collection but also encompassing the integration of existing cartographic resources, a relatively "new" mapping tool has proven to be especially valuable in projects that lie between cartographic mapping and single building documentation: drones. This manuscript discusses both the operational and regulatory aspects of employing drones to capture images and process them with photogrammetric techniques to create digital records for inner areas, with a particular focus on a research project on some inner areas of Southern Calabria. In addition to addressing technical limitations and challenges, the pilot, who is also considered a photogrammetry expert in this paper, must also understand the project's requirements by establishing a dialogue with other specialists who will utilize the photogrammetric outputs. Compared to more traditional and standardized cartographic mapping initiatives covering large areas or restoration and preservation projects focused on individual buildings, the documentation of inner areas using drones occupies an intermediate stage that still lacks a well-defined workflow.Una documentazione metrica precisa e completa degli insediamenti in aree interne presenta sfide uniche per via delle specifiche caratteristiche e delle variabilità che tali aree presentano. Se è vero che una raccolta digitale completa richiede l’uso di vari strumenti, non esclusivamente limitati alla mappatura in sito ma che includa anche l’integrazione delle risorse cartografiche esistenti, uno strumento relativamente nuovo per acquisire e processare immagini con tecniche fotogrammetriche è il drone. Il drone si è rilevato di particolare utilità in quei progetti o studi tra una mappatura a scala territoriale e la documentazione del singolo edificio. Questo articolo riguarda gli aspetti sia normativi che operativi relativi all’uso del drone per catturare immagini e processarle con tecniche fotogrammetriche, in particolare nel caso di piccoli insediamenti in aree interne, a supporto della creazione di archivi digitali, con particolare attenzione al contesto italiano nell’ambito di una ricerca sulle aree interne della Calabria meridionale. L’articolo discute inoltre il dialogo necessario tra il pilota, che qui si intende anche un esperto di fotogrammetria, con gli altri specialisti che utilizzeranno i dati raccolti e processati; ciò anche nell’intenzione di mettere in luce limiti e sfide che questo strumento possiede anche sul piano tecnico. Se confrontato con mappature cartografiche più tradizionali, sia che interessino un progetto a scala territoriale o il restauro di un edificio storico, la mappatura delle aree interne con l’uso del drone occupa una sorta di livello intermedio in cui manca ancora di un flusso di lavoro ben definito.A precise and comprehensive metric documentation of settlements in internal areas presents unique challenges due to the specific characteristics and variability of such regions. While it is true that a complete digital collection requires the use of various tools—not exclusively limited to on-site mapping but also including the integration of existing cartographic resources—a relatively new tool for acquiring and processing images using photogrammetric techniques is the drone. The drone has proven particularly useful in projects or studies that bridge territorial-scale mapping and the documentation of individual buildings. This article addresses both the regulatory and operational aspects related to the use of drones for capturing images and processing them with photogrammetric techniques, particularly in the case of small settlements in internal areas, to support the creation of digital archives, with a specific focus on the Italian context within research on the internal areas of Southern Calabria. The article also discusses the necessary dialogue between the pilot—who is also considered an expert in photogrammetry—and other specialists who will use the collected and processed data, aiming to highlight the limitations and challenges that this tool presents on a technical level. When compared to more traditional cartographic mappings, whether concerning a territorial-scale project or the restoration of a historical building, mapping internal areas using drones occupies a sort of intermediate level that still lacks a well-defined workflow
NETWORK DESIGN IN CLOSE-RANGE PHOTOGRAMMETRY WITH SHORT BASELINE IMAGES
Full text linkThe avaibility of automated software for image-based 3D modelling has changed the way people acquire images for photogrammetric applications. Short baseline images are required to match image points with SIFT-like algorithms, obtaining more images than those necessary for “old fashioned” photogrammetric projects based on manual measurements. This paper describes some considerations on network design for short baseline image sequences, especially on precision and reliability of bundle adjustment. Simulated results reveal that the large number of 3D points used for image orientation has very limited impact on network precision
INTEGRATION BETWEEN BUILDING INFORMATION MODELING AND GEOGRAPHIC INFORMATION SYSTEM FOR HISTORIC BUILDINGS AND SITES: HISTORIC-BIM-GIS
Full text linkThe paper presents a novel prototype of integrated Historic BIM-GIS able to deal with multi-source, -scale, and -temporal information. It combines elements from the cartographic scale to a more detailed level of detail towards the building. It can be defined as a 3D virtual environment with an associate (geo)database able to encapsulate heterogeneous data not limited to products derived from the geometric survey, notwithstanding digital recording and its deliverables play a fundamental role. The system also provides a good interoperability level so that BIM and GIS software can exchange information, avoiding the implementation of functions and tools already available in other software packages. The example proposed in this contribution is related to the system of fortified structures around the city of Sondrio. Here, a single 3D environment was developed to encapsulate information from the cartographic level in an area of more than 135 km2 to the scale of 1:1 for specific architectural elements
Metric Rectification of Spherical Images
Full text linkThis paper describes a method for metric recording based on spherical images, which are rectified to document planar surfaces. The proposed method is a multistep workflow in which multiple rectilinear images are (i) extracted from a single spherical projection and (ii) used to recover metric properties. The workflow is suitable for documenting buildings with small and narrow rooms, i.e., documentation projects where the acquisition of 360 images is faster than the traditional acquisition of several photographs. Two different rectification procedures were integrated into the current implementation: (i) an analytical method based on control points and (ii) a geometric procedure based on two sets of parallel lines. Constraints based on line parallelism can be coupled with the focal length of the rectified image to estimate the rectifying transformation. The calculation of the focal length does not require specific calibrations projects. It can be derived from the spherical image used during the documentation project, obtaining a rectified image with just an overall scale ambiguity. Examples and accuracy evaluation are illustrated and discussed to show the pros and cons of the proposed method
Methods for Ancient Wall Graffiti Documentation: Overview and Applications
Full text linkAncient graffiti are evidence of the past, scattered all over the globe and common to many cultures. Documentation is a crucial step for their study, and must allow for clear interpretation. There are a variety of traditional methods to document ancient graffiti, from sketches to frottages, to contact tracing and photography. Digital instruments and other innovative methods developed during recent years in the field of heritage documentation can also be successfully applied to graffiti, improving the quality of results and increasing their readability. This paper presents the principal methods used for graffiti documentation and discusses the trends over the last few decades; it also presents two different case studies where the principal methods are tested and reviewed
Generation of a multi-scale historic BIM-GIS with digital recording tools and geospatial information
Full text linkThis paper discusses the creation of an integrated historic BIM-GIS for the complex of San Pietro al Monte, an important Romanesque monument in Civate (Italy) inscribed in the UNESCO tentative list with other seven medieval Benedictine settlements. The reason behind the choice of an integrated H-BIM-GIS solution is motivated by the large extension of the considered area (about 30 km2) and the need for multi-scale digital information integrated into a 3D parametric environment. The model includes geospatial information at a territorial scale and in situ digital data capturing the complex at a higher level of detail. The work aims at exploring the pros and cons of a novel parametric 3D environment able to integrate both BIM and GIS data, methods, and processing tools in the case of historic buildings and sites
BIM AND GIS: WHEN PARAMETRIC MODELING MEETS GEOSPATIAL DATA
Full text linkGeospatial data have a crucial role in several projects related to infrastructures and land management. GIS software are able to perform advanced geospatial analyses, but they lack several instruments and tools for parametric modelling typically available in BIM. At the same time, BIM software designed for buildings have limited tools to handle geospatial data. As things stand at the moment, BIM and GIS could appear as complementary solutions, notwithstanding research work is currently under development to ensure a better level of interoperability, especially at the scale of the building. On the other hand, the transition from the local (building) scale to the infrastructure (where geospatial data cannot be neglected) has already demonstrated that parametric modelling integrated with geoinformation is a powerful tool to simplify and speed up some phases of the design workflow. This paper reviews such mixed approaches with both simulated and real examples, demonstrating that integration is already a reality at specific scales, which are not dominated by “pure” GIS or BIM. The paper will also demonstrate that some traditional operations carried out with GIS software are also available in parametric modelling software for BIM, such as transformation between reference systems, DEM generation, feature extraction, and geospatial queries. A real case study is illustrated and discussed to show the advantage of a combined use of both technologies. BIM and GIS integration can generate greater usage of geospatial data in the AECOO (Architecture, Engineering, Construction, Owner and Operator) industry, as well as new solutions for parametric modelling with additional geoinformation
3D MODELING WITH 5K 360° VIDEOS
Full text linkVideo acquisition with 360° (spherical) cameras is becoming increasingly popular for the opportunity to capture the entire scene around the user in a relatively short time. The method can also be attractive for photogrammetric applications. As the overlap between consecutive frames is undoubtedly guaranteed, 3D models can be generated with an automated processing workflow. The paper illustrates the results achieved with 5k 360° videos captured with different Insta360 cameras. As the number of frames can become large, two complementary solutions are proposed to provide approximate initial exterior orientation parameters: The integration of the trajectory captured through GNSS, and the creation of an acquisition plan with a GIS-based application. The availability of approximated EO parameters provides a visibility map between the frames and reduces the computational cost during image matching. Experimental results demonstrate that such preliminary information is necessary for large datasets. Indeed, the photogrammetric processing of the entire dataset without the proposed preliminary EO parameters resulted in unreliable or incomplete orientation results
GNSS assisted photogrammetric reconstruction from combined 360° videos and uav images
Full text linkThis paper introduces an integrated approach utilizing ground data consists of videos captured with a 360° (spherical) camera and aerial data acquired with a UAV equipped with a RTK GNSS module to reconstruct a portion of a small-Town city center and/or a cultural heritage site. Previous research has demonstrated that image blocks oriented with RTK data on camera position can reach centimeter accuracies and can be efficiently used to reconstruct large areas and single monuments. However, some areas like porches, narrow passages and streets cannot be properly reconstructed from an aerial point of view. Conversely, ground-based 360° images offer detailed insights into the terrain and features that may be obscured from an aerial perspective. Integration of those two points of view can increase spatial resolution and coverage for 3D reconstruction. Indeed, the UAV captures large-scale features and topography, while ground-based 360° images focus on intricate details and ground-level characteristics. The possibility to exploit GNSS data acquired by UAV may also be used for GNSS-Assisted image orientation with the aim of reducing or even avoiding, in specific situations, the need for GCPs. The paper explores practical applications of such data integration in the cultural heritage domain demonstrating the efficacy of the integrated approach in scenarios with complex architectures and inaccessible areas
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