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2023 Journal article Open Access OPEN
Quantifying the loss of coral from a bleaching event using underwater photogrammetry and AI-Assisted Image Segmentation
Kopecky K. L., Pavoni G., Nocerino E., Brooks A. J., Corsini M., Menna F., Gallagher J. P., Capra A., Castagnetti C., Rossi P., Gruen A., Neyer F., Muntoni A., Ponchio F., Cignoni P., Troyer M., Holbrook S. J., Schmitt R. J.
Detecting the impacts of natural and anthropogenic disturbances that cause declines in organisms or changes in community composition has long been a focus of ecology. However, a tradeoff often exists between the spatial extent over which relevant data can be collected, and the resolution of those data. Recent advances in underwater photogrammetry, as well as computer vision and machine learning tools that employ artificial intelligence (AI), offer potential solutions with which to resolve this tradeoff. Here, we coupled a rigorous photogrammetric survey method with novel AI-assisted image segmentation software in order to quantify the impact of a coral bleaching event on a tropical reef, both at an ecologically meaningful spatial scale and with high spatial resolution. In addition to outlining our workflow, we highlight three key results: (1) dramatic changes in the three-dimensional surface areas of live and dead coral, as well as the ratio of live to dead colonies before and after bleaching; (2) a size-dependent pattern of mortality in bleached corals, where the largest corals were disproportionately affected, and (3) a significantly greater decline in the surface area of live coral, as revealed by our approximation of the 3D shape compared to the more standard planar area (2D) approach. The technique of photogrammetry allows us to turn 2D images into approximate 3D models in a flexible and efficient way. Increasing the resolution, accuracy, spatial extent, and efficiency with which we can quantify effects of disturbances will improve our ability to understand the ecological consequences that cascade from small to large scales, as well as allow more informed decisions to be made regarding the mitigation of undesired impacts.Source: Remote sensing (Basel) 15 (2023). doi:10.3390/rs15164077
DOI: 10.3390/rs15164077
Metrics:


See at: ISTI Repository Open Access | www.mdpi.com Open Access | CNR ExploRA


2023 Conference article Open Access OPEN
Ancient coins' surface inspection with web-based neural RTI visualization
Righetto L., Gobbetti E., Ponchio F., Traviglia A., De Bernardin M., Giachetti A.
The use of neural encodings has the potential to replace the commonly used polynomial fitting in the analysis of artwork surface based on Reflectance Transformation Imaging (RTI), as it has proved to result in more compact encoding with better relight quality, but it is still not widely used due to the lack of efficient implementations available to practitioners. In this work, we describe an optimized system to encode/decode neural relightable images providing interactive visualization in a web interface allowing multi-layer visualization and annotation. To develop it, we performed several experiments testing different decoder architectures and input processing pipelines, evaluating the quality of the results on specific benchmarks to find the optimal tradeoff between relighting quality and efficiency. A specific decoder has been then implemented for the web and integrated into an advanced visualisation tool. The system has been tested for the analysis of a group of ancient Roman bronze coins that present scarce readability and varying levels of preservation and that have been acquired with a multispectral light dome. Their level of corrosion and degradation, which in some cases hinders the recognition of the images, numerals, or text represented on them, makes the system testing particularly challenging and complex. Testing on such a real case scenario, however, enables us to determine the actual improvement that this new RTI visualization tool can offer to numismatists in their ability to identify the coins.Source: SPIE Optical Metrology, pp. 12620:0D, Munich, Germany, 26-29/06/2023
DOI: 10.1117/12.2674888
Metrics:


See at: ISTI Repository Open Access | www.spiedigitallibrary.org Open Access | doi.org Restricted | CNR ExploRA


2022 Journal article Open Access OPEN
On assisting and automatizing the semantic segmentation of masonry walls
Pavoni G., Giuliani F., De Falco A., Corsini M., Ponchio F., Callieri M., Cignoni P.
In Architectural Heritage, the masonry's interpretation is an essential instrument for analysing the construction phases, the assessment of structural properties, and the monitoring of its state of conservation. This work is generally carried out by specialists that, based on visual observation and their knowledge, manually annotate ortho-images of the masonry generated by photogrammetric surveys. This results in vector thematic maps segmented according to their construction technique (isolating areas of homogeneous materials/structure/texture or each individual constituting block of the masonry) or state of conservation, including degradation areas and damaged parts. This time-consuming manual work, often done with tools that have not been designed for this purpose, represents a bottleneck in the documentation and management workflow and is a severely limiting factor in monitoring large-scale monuments (e.g., city walls). This article explores the potential of AI-based solutions to improve the efficiency of masonry annotation in Architectural Heritage. This experimentation aims at providing interactive tools that support and empower the current workflow, benefiting from specialists' expertise.Source: Journal on computing and cultural heritage (Online) 15 (2022). doi:10.1145/3477400
DOI: 10.1145/3477400
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See at: ISTI Repository Open Access | dl.acm.org Restricted | Journal on Computing and Cultural Heritage Restricted | CNR ExploRA


2022 Journal article Open Access OPEN
A toolbox for measuring heterogeneity and efficiency using zonotopes
Cococcioni M., Grazzi M., Li L., Ponchio F.
In this work, we describe the new command zonotope, which, by resorting to a geometry-based approach, provides a measure of productivity that fully accounts for the existing heterogeneity across firms within the same industry. The method we propose also enables assessment of the extent of multidimensional heterogeneity with applications to fields beyond that of production analysis. Finally, we detail the functioning of the software to perform the related empirical analysis, and we discuss the main computational issues encountered in its development.Source: The Stata journal 22 (2022): 25–59. doi:10.1177/1536867X221083854
DOI: 10.1177/1536867x221083854
Project(s): ISIGrowth via OpenAIRE
Metrics:


See at: ISTI Repository Open Access | The Stata Journal Promoting communications on statistics and Stata Restricted | Archivio della Ricerca - Università di Pisa Restricted | journals.sagepub.com Restricted | CNR ExploRA


2022 Journal article Open Access OPEN
Design and construction of a bending-active plywood structure: the Flexmaps Pavilion
Laccone F., Malomo L., Callieri M., Alderighi T., Muntoni A., Ponchio F., Pietroni N., Cignoni P.
Mesostructured patterns are a modern and efficient concept based on designing the geometry of structural material at the meso-scale to achieve desired mechanical performances. In the context of bending-active structures, such a concept can be used to control the flexibility of the panels forming a surface without changing the constituting material. These panels undergo a formation process of deformation by bending, and application of internal restraints. This paper describes a new constructional system, FlexMaps, that has initiated the adoption of bending-active mesostructures at the architectural scale. Here, these modules are in the form of four-arms spirals made of CNC-milled plywood and are designed to reach the desired target shape once assembled. All phases from the conceptual design to the fabrication are seamlessly linked within an automated workflow. To illustrate the potential of the system, the paper discusses the results of a demonstrator project entitled FlexMaps Pavilion (3.90x3.96x3.25 meters) that has been exhibited at the IASS Symposium in 2019 and more recently at the 2021 17th International Architecture Exhibition, La Biennale di Venezia. The structural response is investigated through a detailed structural analysis, and the long-term behavior is assessed through a photogrammetric survey.Source: Journal of the International Association for Shell and Spatial Structures 63 (2022): 98–114. doi:10.20898/j.iass.2022.007
DOI: 10.20898/j.iass.2022.007
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See at: ISTI Repository Open Access | CNR ExploRA


2022 Conference article Open Access OPEN
Cultural Heritage 3D data on the Web: issues and perspectives
Potenziani M., Ponchio F., Callieri M., Cignoni P., Scopigno R.
Les modèles numériques 3D sont unanimement considérés comme un atout inestimable pour l'étude, la gestion et la promotion du patrimoine culturel. L'urgence de COVID-19 a accéléré la tendance commune à travailler à distance et, pour le patrimoine culturel, la présentation, le partage et l'accès aux données 3D en ligne sont désormais perçus comme une nécessité. Malheureusement, l'absence de méthodologies, d'outils et d'infrastructures standard rend difficile le passage du stockage local à la gestion en ligne de données 3D complexes. Dans cette contribution, nous souhaitons évaluer l'état de l'art de l'utilisation avancée de la 3D sur le web, en soulignant les besoins actuels, en présentant quelques études de cas et en explorant les perspectives futures.Source: Heritage for the Future, Science for Heritage: A European Adventure for Research and Innovation, pp. 378–383, Paris, France, 15-16/03/2022

See at: ISTI Repository Open Access | www.heritageresearch-hub.eu Open Access | CNR ExploRA


2022 Conference article Open Access OPEN
Ebb & flow: uncovering Costantino Nivola's Olivetti sandcast through 3D fabrication and virtual exploration
Ahsan M., Altea G., Bettio F., Callieri M., Camarda A., Cignoni P., Gobbetti E., Ledda P., Lutzu A., Marton F., Mignemi G., Ponchio F.
We report on the outcomes of a large multi-disciplinary project targeting the physical reproduction and virtual documentation and exploration of the Olivetti sandcast, a monumental (over 100m2) semi-abstract frieze by the Italian sculptor Costantino Nivola. After summarizing the goal and motivation of the project, we provide details on the acquisition and processing steps that led to the creation of a 3D digital model. We then discuss the technical details and the challenges that we have faced for the physical fabrication process of a massive physical replica, which was the centerpiece of a recent exhibition. We finally discuss the design and application of an interactive web-based tool for the exploration of an annotated virtual replica. The main components of the tool will be released as open source.Source: GCH 2022 - Eurographics Workshop on Graphics and Cultural Heritage, pp. 85–94, Delft, The Netherlands, 28-30/09/2022
DOI: 10.2312/gch.20221230
Metrics:


See at: diglib.eg.org Open Access | ISTI Repository Open Access | doi.org Restricted | CNR ExploRA


2022 Report Open Access OPEN
ARIADNEplus D15.2 - Final report on ARIADNEplus services
Marberg J. F., Bardi A., Vlachidis A., Meghini C., Binding C., Tudhope D., Sinibaldi F., Ponchio F., Mangiacrapa F., Radman-Livaja I., Callieri M., Potenziani M., Lamé M., Assante M., Pagano P., Hermon S., Vassallo V.
This deliverable describes the activities carried out within Work Package 15 (WP15) of the ARIADNEplus project by the different partners and describes the results achieved. The work package consists of several individual tasks and subtasks with the overall goal to develop and provide useful services to archaeologists. This means the work package is by nature heterogeneous with stand-alone tasks and services. Efforts have been made to facilitate collaboration between the individual tasks through joint work package meetings. This has resulted in new cross-task contacts being made, and some sharing of expertise to improve services has been done. A service design template aligning the ARIADNEplus services with the requirements from European Open Science Cloud (EOSC) has been created. In connection with this, the ARIADNEplus AO-CAT ontology has been adapted to the requirements from EOSC Resource Data Model (Task 15.1). The Visual Media Service (Task 15.2.1) has had a new format added, allowing for 2D visualisation of LIDAR data in DEM format. In addition, three other standards have been added: gITF, ThreeJS and IIIF, supporting various functionality in the service. The service has also been adapted to support integration with the ARIADNEplus infrastructure in D4Science. A visual wizard has been defined to guide Visual Media Service users to add hotspots to a 3D scene easily and quickly. This extension, initially implemented in 3DHOP will allow archaeologists to create interactive links from the digital 3D model to the related documentation without writing any source code (Task 15.2.2). Task 15.2.3 reworked the Online 3D Database System for Endangered architectural and archaeological Heritage in the south Eastern MEditerRAnea area (EpHEMERA). EpHEMERA is a service provided by the Cyprus Institute to visualize in 3D archaeological excavations, ancient buildings, and their related documentation. In EpHEMERA, it is possible to visualise, online and through standard web browsers, 3D architectural and archaeological models (classified according to a specific type of risk), query the database system and retrieve metadata attached to each digital object, and extract geometric and morphological information about the Cultural Heritage asset. The visualisation and annotation tool of the TSS project have been ported to the OpenLime library and integrated into the Visual Media Service (Task 15.2.1). An additional layer of SVG annotations have been developed and added to the service. The Annotation service have been used and improved in three different pilot projects. (Task 15.3.2) Various strands of work have been done improving services for text mining and Natural Language Processing (Task 15.4). One of these efforts has been building upon the outcomes of the preceding ARIADNE project. A set of archaeological Named Entity Recognition NLP pipelines were reconfigured and deployed for easier use on the General Architecture for Text Engineering (GATE) cloud. Another effort has been on extracting temporal archaeological information using two different parallel approaches, normalisation and named entity recognition. A Python development platform has been used to unify the various services. A Vocabulary Annotation Tool (Task 15.3.1) was developed using the same platform, as part of Task 15.4. The tool facilitates the locating and tagging of vocabulary terms within free text and outputs suggested subject annotations in a range of formats. The GeoPortal service (Task 15.5) is a new REST service designed to manage complex spatio-temporal documents defined by metadata profiles. It was released as a component of the gCube framework. A prototype using the service was deployed and operated to manage archaeological excavation projects (Task 15.7). Two services for querying the RDF AO-Cat metadata records aggregated by the ARIADNEplus Infrastructure was established (Task 15.6): a full-text index service and a SPARQL endpoint. The full- text index service is based on OpenSearch and supports the needed query functionality of the ARIADNEplus portal. The SPARQL endpoint allows performance of semantic queries on the RDF records within the ARIADNEplus data and knowledge cloud.Source: ISTI Project report, ARIADNEplus, D15.2, 2022
Project(s): ARIADNEplus via OpenAIRE

See at: ISTI Repository Open Access | CNR ExploRA


2021 Contribution to book Restricted
Virtual clones for cultural heritage applications
Potenziani M., Banterle F., Callieri M., Dellepiane M., Ponchio F., Scopigno R.
Digital technologies are now mature for producing high quality digital replicas of Cultural Heritage (CH) artifacts. The research results produced in the last decade have shown an impressive evolution and consolidation of the technologies for acquiring high-quality digital 3D models, encompassing both geometry and color (or, better, surface reflectance properties). Some recent technologies for constructing 3D models enriched by a high-quality encoding of the color attribute will be presented. The focus of this paper is to show and discuss practical solutions, which could be deployed without requiring the installation of a specific or sophisticated acquisition lab setup. In the second part of this paper, we focus on new solutions for the interactive visualization of complex models, adequate for modern communication channels such as the web and the mobile platforms. Together with the algorithms and approaches, we show also some practical examples where high-quality 3D models have been used in CH research, restoration and conservation.Source: From Pen to Pixel - Studies of the Roman Forum and the Digital Future of World Heritage, edited by Fortini Patrizia, Krusche Krupali, pp. 225–233. Roma: L'Erma di Bretschneider, 2021

See at: www.lerma.it Restricted | CNR ExploRA


2021 Journal article Open Access OPEN
TagLab: AI-assisted annotation for the fast and accurate semantic segmentation of coral reef orthoimages
Pavoni G., Corsini M., Ponchio F., Muntoni A., Edwards C., Pedersen N., Sandin S., Cignoni P.
Semantic segmentation is a widespread image analysis task; in some applications, it requires such high accuracy that it still has to be done manually, taking a long time. Deep learning-based approaches can significantly reduce such times, but current automated solutions may produce results below expert standards. We propose agLab, an interactive tool for the rapid labelling and analysis of orthoimages that speeds up semantic segmentation. TagLab follows a human-centered artificial intelligence approach that, by integrating multiple degrees of automation, empowers human capabilities. We evaluated TagLab's efficiency in annotation time and accuracy through a user study based on a highly challenging task: the semantic segmentation of coral communities in marine ecology. In the assisted labelling of corals, TagLab increased the annotation speed by approximately 90% for nonexpert annotators while preserving the labelling accuracy. Furthermore, human-machine interaction has improved the accuracy of fully automatic predictions by about 7% on average and by 14% when the model generalizes poorly. Considering the experience done through the user study, TagLab has been improved, and preliminary investigations suggest a further significant reduction in annotation times.Source: Journal of field robotics (2021). doi:10.1002/rob.22049
DOI: 10.1002/rob.22049
Metrics:


See at: onlinelibrary.wiley.com Open Access | ISTI Repository Open Access | CNR ExploRA


2021 Conference article Open Access OPEN
TagLab: A human-centric AI system for interactive semantic segmentation
Pavoni G., Corsini M., Ponchio F., Muntoni A., Cignoni P.
Fully automatic semantic segmentation of highly specific semantic classes and complex shapes may not meet the accuracy standards demanded by scientists. In such cases, human-centered AI solutions, able to assist operators while preserving human control over complex tasks, are a good trade-off to speed up image labeling while maintaining high accuracy levels. TagLab is an open-source AI-assisted software for annotating large orthoimages which takes advantage of different degrees of automation; it speeds up image annotation from scratch through assisted tools, creates custom fully automatic semantic segmentation models, and, finally, allows the quick edits of automatic predictions. Since the orthoimages analysis applies to several scientific disciplines, TagLab has been designed with a flexible labeling pipeline. We report our results in two different scenarios, marine ecology, and architectural heritage.Source: Human Centered AI Workshop at NeurIPS 2021 - Thirty-fifth Conference on Neural Information Processing Systems, Online event, 13/12/2021
DOI: 10.48550/arxiv.2112.12702
Metrics:


See at: arXiv.org e-Print Archive Open Access | ISTI Repository Open Access | doi.org Restricted | CNR ExploRA


2021 Report Open Access OPEN
ARIADNEplus D15.1 - Mid-term interim report on ARIADNEplus services
Marberg J. F., Bardi A., Meghini C., Binding C., Tudhope D., Sinibaldi F., Ponchio F., Mangiacrapa F., Radman-Livaja I., Potenziani M., Lamé M., Assante M., Pagano P., Hermon S., Vassallo V.
This deliverable describes the activities carried out during the first half of the ARIADNEplus project within Work Package 15 (WP15) by the different partners and describes the results achieved thus far. The work package consists of several individual tasks and subtasks with the overall goal to develop and provide useful services to archaeologists. This means that the work package in itself is by nature heterogeneous with stand-alone tasks and services. Efforts have been made to facilitate collaboration between the individual tasks through joint work package meetings. This has resulted in new cross-task contacts being made, and some sharing of expertise to improve services has been done. A service design template aligning the ARIADNEplus services with the requirements from the European Open Science Cloud (EOSC) has been created. In connection to this, the ARIADNEplus AOCAT ontology has been adapted to the requirements from the EOSC Resource Data Model. The Visual Media Service (Task 15.2.1) has had a new format added, allowing for 2D visualization of LIDAR data in DEM format. In addition, three other standards have been added: gITF, ThreeJS and IIF, supporting various functionalities in the service. The service has also been adapted to support integration with the ARIADNEplus infrastructure in D4Science. A visual wizard has been defined to guide Visual Media Service users to add hotspots to a 3D scene easily and quickly. This extension, initially implemented in 3DHOP, will allow archaeologists to create interactive links from the digital 3D model to the related documentation without writing any source code (Task 15.2.2). To integrate the EpHEMERA service (Task 15.2.3) into the ARIADNEplus infrastructure environment, a revision of the service is needed. As this revision needs to be based upon user needs and comments, tutorials have been created and a user survey has been prepared, distributed, and analysed. Revision of the service and implementation of new components have started. A prototype of an image annotation service has been created based on the OpenAnnotation format, which is intended to be integrated with the Visual Media Service. The first prototype supports vector annotation of relightable images. The GeoPortal service (Task 15.5) is a new REST service designed to manage complex space-temporal documents defined by metadata Profiles. It has been released as a component of the gCube framework. A prototype using the service has been deployed and operated to manage archaeological excavation projects (Task 15.7). Two services for querying the RDF AO-Cat metadata records aggregated by the ARIADNEplus Aggregative Infrastructure has been established (Task 15.6): a full-text index service and a SPARQL endpoint. The full-text index service is based on Elasticsearch and supports the needed query functionality of the ARIADNEplus portal. The SPARQL endpoint allows to perform semantic queries on the RDF records in the ARIADNEplus data and knowledge cloud.Source: ISTI Project report, ARIADNEplus, D15.1, 2021
Project(s): ARIADNEplus via OpenAIRE

See at: ISTI Repository Open Access | CNR ExploRA


2020 Journal article Open Access OPEN
Effective annotations over 3D models
Ponchio F., Callieri M., Dellepiane M., Scopigno R.
Annotation support in interactive systems is often considered a simple task by the CG community, since it entails the apparently easy selection of a region and its connection with some information. The reality appears more complex. The scope of this paper is twofold: first, to review the status of this domain, discussing and characterizing several approaches proposed in literature to manage annotations over geometric models; second, to present in detail an innovative solution proposed and assessed in the framework of Cultural Heritage (CH) applications, called ClippingVolumes. At the annotation definition stage ClippingVolumes uses 3D data to characterize the annotation region; subsequently, annotations are visualized by adopting a two-pass rendering solution which uses stencil buffers, thus without introducing new geometric elements, changing the topology or duplicating geometry elements. It solves most of the issues that afflict the current state of the art, such as fragmentation, annotation transfer to multiple representations, and multi-resolution data encoding. The latter is a mandatory requirement to produce efficient web-based systems. We implemented and we fully tested this approach in the framework of a complex system that supports the documentation of CH restoration projects.Source: Computer graphics forum (Online) 39 (2020): 89–105. doi:10.1111/cgf.13664
DOI: 10.1111/cgf.13664
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See at: ISTI Repository Open Access | Computer Graphics Forum Restricted | onlinelibrary.wiley.com Restricted | CNR ExploRA


2020 Journal article Closed Access
ReviewerNet: A visualization platform for the selection of academic reviewers
Salinas M., Giorgi D., Ponchio F., Cignoni P.
We propose ReviewerNet, an online, interactive visualization system aimed to improve the reviewer selection process in the academic domain. Given a paper submitted for publication, we assume that good candidate reviewers can be chosen among the authors of a small set of pertinent papers; ReviewerNet supports the construction of such set of papers, by visualizing and exploring a literature citation network. The system helps journal editors and Program Committee members to select reviewers that do not have any conflict-of-interest and are representative of different research groups, by visualising the careers and co-authorship relations of candidate reviewers. The system is publicly available, and is demonstrated in the field of Computer Graphics.Source: Computers & graphics 89 (2020): 77–87. doi:10.1016/j.cag.2020.04.006
DOI: 10.1016/j.cag.2020.04.006
Metrics:


See at: Computers & Graphics Restricted | www.sciencedirect.com Restricted | CNR ExploRA


2020 Journal article Open Access OPEN
A bending-active twisted-arch plywood structure: computational design and fabrication of the FlexMaps Pavilion
Laccone F., Malomo L., Pérez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to efficiently produce complex curved shapes from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium configuration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match specific bending requests, namely the global curvature of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which defines the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplified pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arch that fits a bounding box of 3.90x3.96x3.25 meters. This case study serves to test the applicability of this methodology at the architectural scale. The structure is validated via FE analyses and the fabrication of the full scale prototype.Source: SN Applied Sciences 2 (2020). doi:10.1007/s42452-020-03305-w
DOI: 10.1007/s42452-020-03305-w
Project(s): EVOCATION via OpenAIRE
Metrics:


See at: SN Applied Sciences Open Access | link.springer.com Open Access | SN Applied Sciences Open Access | ISTI Repository Open Access | CNR ExploRA


2020 Journal article Open Access OPEN
Neural reflectance transformation imaging
Dulecha T. G., Fanni F. A., Ponchio F., Pellacini F., Giachetti A.
Reflectance transformation imaging (RTI) is a computational photography technique widely used in the cultural heritage and material science domains to characterize relieved surfaces. It basically consists of capturing multiple images from a fixed viewpoint with varying lights. Handling the potentially huge amount of information stored in an RTI acquisition that consists typically of 50-100 RGB values per pixel, allowing data exchange, interactive visualization, and material analysis, is not easy. The solution used in practical applications consists of creating "relightable images" by approximating the pixel information with a function of the light direction, encoded with a small number of parameters. This encoding allows the estimation of images relighted from novel, arbitrary lights, with a quality that, however, is not always satisfactory. In this paper, we present NeuralRTI, a framework for pixel-based encoding and relighting of RTI data. Using a simple autoencoder architecture, we show that it is possible to obtain a highly compressed representation that better preserves the original information and provides increased quality of virtual images relighted from novel directions, especially in the case of challenging glossy materials. We also address the problem of validating the relight quality on different surfaces, proposing a specific benchmark, SynthRTI, including image collections synthetically created with physical-based rendering and featuring objects with different materials and geometric complexity. On this dataset and as well on a collection of real acquisitions performed on heterogeneous surfaces, we demonstrate the advantages of the proposed relightable image encoding.Source: The visual computer (2020): 2161–2174. doi:10.1007/s00371-020-01910-9
DOI: 10.1007/s00371-020-01910-9
Metrics:


See at: The Visual Computer Open Access | link.springer.com Open Access | The Visual Computer Open Access | ISTI Repository Open Access | CNR ExploRA


2020 Journal article Open Access OPEN
Real-World textured things: a repository of textured models generated with modern photo-reconstruction tools
Maggiordomo A., Ponchio F., Cignoni P., Tarini M.
We are witnessing a proliferation of textured 3D models captured from the real world with automatic photo-reconstruction tools by people and professionals without a proper technical background in computer graphics. Digital 3D models of this class come with a unique set of characteristics and defects - especially concerning their parametrization - setting them starkly apart from 3D models originating from other, more traditional, sources. We study this class of 3D models by collecting a significant number of representatives and quantitatively evaluating their quality according to several metrics. These include a new invariant metric we carefully design to assess the amount of fragmentation of the UV map, which is one of the main weaknesses potentially hindering the usability of these models. Our results back the widely shared notion that models of this new class are still not fit for direct use in downstream applications (such as videogames), and require challenging processing steps. Regrettably, existing automatic geometry processing tools are not always up to the task: for example, we verify that the available tools for UV optimization often fail due to mesh inconsistencies, geometric and topological noise, excessive resolution, or other factors; moreover, even when an output is produced, it rarely represents a significant improvement over the input (according to the aforementioned measures). Therefore, we argue that further advancements are required by the computer graphics and geometry processing communities specifically targeted at this class of models. Towards this goal, we share the models we collected in this study as a new public repository, Real-World Textured Things (RWTT), intended as a benchmark to systematic field-test and compare future algorithms. RWTT consists of 568 carefully selected textured 3D models representative of the most popular photo-reconstruction tools currently available. We also provide a web interface to browse the dataset by the metadata we collected during our experiments and a tool, TexMetro, to compute the same set of measures on generic UV mapped datasets.Source: Computer aided geometric design 83 (2020). doi:10.1016/j.cagd.2020.101943
DOI: 10.1016/j.cagd.2020.101943
DOI: 10.48550/arxiv.2004.14753
Project(s): ENCORE via OpenAIRE
Metrics:


See at: arXiv.org e-Print Archive Open Access | Computer Aided Geometric Design Open Access | Archivio Istituzionale della Ricerca dell'Università degli Studi di Milano Open Access | Computer Aided Geometric Design Restricted | doi.org Restricted | www.sciencedirect.com Restricted | CNR ExploRA


2020 Conference article Open Access OPEN
Another Brick in the Wall: Improving the Assisted Semantic Segmentation of Masonry Walls
Pavoni G., Giuliani F., De Falco A., Corsini M., Ponchio F., Callieri M., Cignoni P.
In Architectural Heritage, the masonry's interpretation is an essential instrument for analyzing the construction phases, the assessment of structural properties, and the monitoring of its state of conservation. This work is generally carried out by specialists that, based on visual observation and their knowledge, manually annotate ortho-images of the masonry generated by photogrammetric surveys. This results in vectorial thematic maps segmented according to their construction technique (isolating areas of homogeneous materials/structure/texture) or state of conservation, including degradation areas and damaged parts. This time-consuming manual work, often done with tools that have not been designed for this purpose, represents a bottleneck in the documentation and management workflow and is a severely limiting factor in monitoring large-scale monuments (e.g.city walls). This paper explores the potential of AI-based solutions to improve the efficiency of masonry annotation in Architectural Heritage. This experimentation aims at providing interactive tools that support and empower the current workflow, benefiting from specialists' expertise.Source: 18th Eurographics Workshop on Graphics and Cultural Heritage, pp. 43–51, Online event, 18-19/11/2020
DOI: 10.2312/gch.20201291
Metrics:


See at: ISTI Repository Open Access | CNR ExploRA


2019 Conference article Open Access OPEN
FlexMaps Pavilion: a twisted arc made of mesostructured flat flexible panels
Laccone F., Malomo L., Perez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to eciently produce complex curved shapes starting from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium conguration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match the global curvature (i.e., bending requests) of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which denes the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplied pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arc that ts a bounding box of 3.90x3.96x3.25 meters.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 498–504, Barcelona, 7-10/10/2019

See at: ISTI Repository Open Access | CNR ExploRA


2019 Other Unknown
Three Armenian Manuscripts from Tuscany
Callieri M., Pingi P., Potenziani M., Ponchio F., Scopigno R.
For the temporary exhibition "Three Armenian Manuscripts from Tuscany", taking palce at the Matenadaran Museum (Jerevan, Armenia) from June 9th 2019 to January 9 2020, The Visual Computing Lab of ISTI-CNR created a multimedia interactive kiosk presenting to the museum visitors the pages of the codices and the rooms of the libraries that preserved the books in their long life. The photographic campaign of the codices and buildings has also been used in the monographic volume "Three Armenian Manuscripts from Tuscany (13th - 14th century)", by Anna Rita Fantoni e Giovanna Rasario. Mandragora, Firenze. 2019. ISBN 978-88-7461-475-2 The Kiosk presents, commented by the texts edited by the experts Anna Rita Fantoni e Giovanna Rasario, high-res 360° panorama images of ther libraries (Biblioteca Medicea Laurenziana and Biblioteca di S. Matteo), high-res images of selected pages of the three codices displayed int he exhibition, and relightable RTI images of the decorated cover of one of the codices and of a parchment page illuminated in gold. The Kiosk is based on web technologies: this makes possible the installation on a stand-alone PC (like in the exhibition) but also a web publishing, linked just above. The generation of RTI, and the web visualization of RTI and multiresolution images is managed by the library Relight, developed by ISTI-CNR.

See at: CNR ExploRA | vcg.isti.cnr.it