In recent years, a growing interest in the 3ddigitisation of museum assets has been pushed by the evident advantages of digital copies in supporting and advancing the knowledge, preservation and promotion of historic...
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In recent years, a growing interest in the 3ddigitisation of museum assets has been pushed by the evident advantages of digital copies in supporting and advancing the knowledge, preservation and promotion of historical artefacts. Realising photo-realistic and precise digital twins of medium and small-sized movable objects implies several operations, still hiring open research problems and hampering the complete automation andderivation of satisfactory results while limiting processing time. The work examines some recurrent issues and potential solutions, summing up several experiences of photogrammetric-based massive digitisation projects. In particular, the article presents some insights into three crucial aspects of the photogrammetric pipeline. The first experiments tackle the depth of Field (doF) problem, especially when digitising small artefacts with macro-lenses. On the processing side, two decisive and time-consuming tasks are instead investigated: background masking and point cloud editing, exploring and proposing automatic solutions for speeding up the reconstruction process.
The automatic generation of structured3d model from point clouds is a primary focus for a lot of researches in the area of 3d modelling and HBIM. The use of procedural modelling techniques, based on set of geometric ...
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The automatic generation of structured3d model from point clouds is a primary focus for a lot of researches in the area of 3d modelling and HBIM. The use of procedural modelling techniques, based on set of geometric rules, is spreading the construction of parametric objects and processes for survey data mapping. In this research field one of the most common methodological approach consists in testing different procedures based on use of specific data from point cloud. One of the main problem to solve is to define the best parameters to use in relation to geometric features of different architectural element and what are the data to extract from point cloud. Starting from shape grammar approach, the main goal of our research is to define 3d parametric models for ribbed vaults suitable to generate 3d smart model for different uses. Most researches in this area deal the case of rectangular or square plan vaults, we addressed the case of trapezoidal vaults anddifferent rules used for apsidal vaults tracing. Our aim is to define an adaptive parametric model that we can use to generate a 3d ideal model or a mixed reality based model. In order to evaluate our tool we compared two 3d models with point clouds: the first is based on geometric rules from sources, the second is based on some specific data from point cloud. Testing the tool on two gothic churches in Naples, the church of S. Lorenzo and the church of *** di donnaregina, we are going to improve it.
In recent decades, the significant advances in digital technologies applied to cultural heritage have led to profound transformations in the activities of protection, conservation and enhancement. A current field of e...
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In recent decades, the significant advances in digital technologies applied to cultural heritage have led to profound transformations in the activities of protection, conservation and enhancement. A current field of experimentation concerns 'rapid mapping' survey techniques with mobile mapping system (MMS). The use of these methodologies is increasingly widespread for the diagnostic and monitoring phases of the architectures. The potential of these techniques are manifold: these systems record, in a short time, a large number of information with a rather high level of accuracy. In particular, the research presented here has studied an 'innovative' Lidar mobile mapping methodology, NavVis VLX, with experimental perspectives, for the survey of the Cripta of the Cathedral of San Matteo in Salerno (Italy).
Image stabilisation (IS) is a family of approaches whose aim is to reduce motion blur in still images and shaking effect in video frames. A variety of techniques are currently implemented in cameras and camcorders: so...
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Image stabilisation (IS) is a family of approaches whose aim is to reduce motion blur in still images and shaking effect in video frames. A variety of techniques are currently implemented in cameras and camcorders: some involve hardware solutions, other are software approaches. In general, IS for still photography entails hardware in-camera or in-lens solutions. Video stabilisation, on the other hand, can be accomplished with software algorithms, either in real-time within the camera or in post-processing. Whereas IS aids photography and video making, its influence on the photogrammetric 3d modelling process has not been investigated. This article addresses this aspect. To this purpose, several laboratory and real-world tests were carried out, whose results showed that IS must be disabled when accuracy matters in photogrammetric projects. details are provided in the manuscript.
The aim of this communication is to present the advantages anddisadvantages of a Scan-to-BIM process applied to a heritage building in order to obtain advanced technical drawings to be used in the analysis and illust...
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The aim of this communication is to present the advantages anddisadvantages of a Scan-to-BIM process applied to a heritage building in order to obtain advanced technical drawings to be used in the analysis and illustration of the project. The whole process described includes: the survey planification anddata acquisition with a Terrestrial Laser Scanner;the processing and cleaning of the point cloud;the 3d mathematical modelling;a proposal for semi-automatic modelling of organic elements;and the import of the final model into a BIM environment. Rhinoceros (McNeel) and Revit (Autodesk) are the main programs used. The crucial aspect of this workflow is found at the moment of importing the geometrical model into Revit, having to accommodate the criteria of this program in terms of tolerances, geometric structure of the solids, incompatibilities with NURBS libraries, etc. The result is a BIM model divided into families and subcategories where visual attributes can be assigned per element, parameterized and other visual information can be added (orthophotographs, wireframe analysis drawings, etc.). In other words, a 3d model from which highly configurable advanced representations (plans, vertical sections, perspectives, isometric exploded view, etc.) can be obtained and with which to generate analyses from the field of Architectural Graphic Expression.
The world is a complex subject whose dynamic range between dark and light cannot be captured by digital cameras. The range of light that can be measured and recorded by a single exposure, is too limited and adapted on...
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A workflow for editing and rendering 360 degrees images (also called spherical or equirectangular images) is illustrated anddiscussed. The aim was to develop a novel procedure able to overcome limitations induced by ...
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A workflow for editing and rendering 360 degrees images (also called spherical or equirectangular images) is illustrated anddiscussed. The aim was to develop a novel procedure able to overcome limitations induced by deformations in images acquired with low-cost 360 degrees cameras. Editing and rendering are carried on equirectangular projections using a dynamic procedure that turns images into traditional central perspectives, enabling the user to change viewing directions, modify digital content, and store the changes in the original files. Integration of the rendered projections with traditional outputs of digital recording operations as well as other deliverables of the architectural restoration project is also discussed. Finally, the development of a web-GIS application that stores and shares multiple deliverables (including the newly proposed renders) is presented.
The survey and modeling of spatial grid structures is often a challenging task to solve, due to the many bottlenecks present in the reverse modelling process. Geometrical and material complexity, scale variation, shad...
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The survey and modeling of spatial grid structures is often a challenging task to solve, due to the many bottlenecks present in the reverse modelling process. Geometrical and material complexity, scale variation, shadows effects, low accessibility, mismatch between similar elements, metrical validation, data management are all critical passages. They must be solved to obtain a reliable data able to solve the system maintenance and intervention requirements. In these cases, in particular, when the structure is difficult to be accessed, it is essential to plan an integrated survey approach. This paper shows how the survey and modelling of an impressive structure was carried out using both TLS and RPAS photogrammetry. After being validated, the data is integrated into a single point cloud that completely describes the structure, eliminating shadow areas and hidden parts. In the modeling process, particular attention was paid to verifying the correspondence between as-built and project. Finally, an element of particular interest is represented by the attempt to recognize the individual construction components belonging to specified geometric anddimensional classes, with the advantage of obtaining a complete model that is as faithful as possible to the real situation of the structure.
The Goethe Elephant skull is a cultural object of great interest. For the highly accurate 3ddigitisation of the object, a hand-held3d scanning system (Creaform GO!Scan) and Structure-from-Motion (dSLR camera) were u...
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The Goethe Elephant skull is a cultural object of great interest. For the highly accurate 3ddigitisation of the object, a hand-held3d scanning system (Creaform GO!Scan) and Structure-from-Motion (dSLR camera) were used. The aim is a complete spatial reconstruction with a resolution of 0.5 mm and an accuracy level of approximate 0.5 mm. The skull consists of three parts, which have very complex but also very simple surface structures. For both methods the data acquisition and processing is described in detail. In both cases, a complete textured meshed3d model could be calculated without shadows due to the use of camera-fixed lighting. The 3d models fulfil the desired target resolution and accuracy, verified by independent reference lengths and by the manufacturer's specifications. In addition, the colour values of the texture were calibrated with the help of the ColorChecker digital SG. A visual and geometric comparison of the two models shows that both methods are very well suited for high-precision 3d object reconstruction on a similar level of accuracy. Furthermore, the advantages anddisadvantages of the methods are compared. The main advantage of the applied hand-held scanner is the real-time verification of the model during data acquisition. The established SfM convinces with its flexibility regarding resolution and camera positioning.
This meta-analysis was conducted to systematically evaluate the short-term efficacy and safety of the three-dimensional (3d) reconstructionvisualization technology (3d-RVT) technique for hepatectomy. A systematic lit...
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This meta-analysis was conducted to systematically evaluate the short-term efficacy and safety of the three-dimensional (3d) reconstructionvisualization technology (3d-RVT) technique for hepatectomy. A systematic literature search was used to gather information on the 3dreconstructionvisualization technology technique for hepatectomy from retrospective cohort studies and comparative studies. The retrieval period was up to March 2022. Publications andconference papers in English were manually searched and references in bibliographies traced. After evaluating the quality of selected studies, a metaanalysis was conducted using Review Manager 5.1 software. We included 12 studies comprising 2053 patients with liver disease. Our meta-results showed that 3d-RVT significantly shortened operation times [weighted mean differences (WMd) = -29.36;95% confidence interval (CI): -55.20 to -3.51;P = 0.03], reduced intraoperative bleeding [WMd = -93.53;95% CI: -152.32 to -34.73;P = 0.002], reduced blood transfusion volume [WMd = -66.06;95% CI: -109.13 to -22.99;P = 0.003], and shortened hospital stays [WMd = -1.90;95% CI: -3.05 to -0.74;P = 0.001]. Additionally, the technique reduced the use of hepatic inflow occlusion and avoided overall postoperative complications [odds ratio (OR) = 0.60;95% CI: 0.46 to 0.79;P < 0.001]. 3d-RVT is safe and effective for liver surgery and provides safety assessments before anatomical hepatectomy.(c) 2023 Asian Surgical Association and Taiwan Robotic Surgery Association. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-Nd license (http://***/ licenses/by-nc-nd/4.0/).
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