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Item Challenges in the Digitisation of a High-reflective Artwork(The Eurographics Association, 2021) Catalano, Chiara Eva; Brunetto, Erika; Mortara, Michela; Pizzi, Corrado; Hulusic, Vedad and Chalmers, AlanIn this paper we report about the photogrammetric acquisition and reconstruction of a contemporary artwork, performed by offthe- shelf software. The ceramic piece of art is "Il Libro d'Oro del Terzo Paradiso" ("The Golden Book of the Third Paradise") by Michelangelo Pistoletto, accessed and studied in the framework of a regional project. This artefact is particularly challenging. On the one hand, it is golden coated and, as such, highly reflective. Hence, images are likely to suffer from highlight spots, shadows or self-reflections, and the reconstructed point cloud is typically noisy. On the other hand, the object exhibits simple geometry, mainly composed of planar surfaces, and is highly symmetric; however, it possesses detail features and undercuts. The symmetric nature of the object and reflections misled the image alignment, and the noise in the data turned out to be of the same scale as the detail features. We will discuss all the steps of the process, aimed at obtaining a high quality and accurate 3D model using low-cost tools.Item Virtual Dance Museum: the Case of Greek/Cypriot Folk Dancing(The Eurographics Association, 2021) Aristidou, Andreas; Andreou, Nefeli; Charalambous, Loukas; Yiannakidis, Anastasios; Chrysanthou, Yiorgos; Hulusic, Vedad and Chalmers, AlanIn this paper, we have designed and developed a virtual dance museum to provide the technological tools that allow for widely educating the public, most specifically the youngest generations, about the story, costumes, music, and history of our dances. The holistic documentation of our intangible cultural heritage creations is a critical necessity for the preservation and the continuity of our identity as Europeans. In that direction, we have employed a specially designed relational database schema that holistically structures the information within the database, and is ideal for archiving, presenting, further analyzing, and re-using dance motion data. Data have been retargeted to a virtual character, dressed with traditional uniform and simulated to achieve realism. The users can view and interact with the archived data using advanced 3D character visualization in three ways: via an online 3D virtual environment; in virtual reality using headset; and in augmented reality, where the 3D characters can co-inhabit the real world. Our museum is publicly accessible, and also enables motion data reusability, facilitating dance learning applications through gamification.Item Entropy-driven Progressive Compression of 3D Point Clouds(The Eurographics Association and John Wiley & Sons Ltd., 2024) Zampieri, Armand; Delarue, Guillaume; Bakr, Nachwa Abou; Alliez, Pierre; Hu, Ruizhen; Lefebvre, Sylvain3D point clouds stand as one of the prevalent representations for 3D data, offering the advantage of closely aligning with sensing technologies and providing an unbiased representation of a measured physical scene. Progressive compression is required for real-world applications operating on networked infrastructures with restricted or variable bandwidth. We contribute a novel approach that leverages a recursive binary space partition, where the partitioning planes are not necessarily axis-aligned and optimized via an entropy criterion. The planes are encoded via a novel adaptive quantization method combined with prediction. The input 3D point cloud is encoded as an interlaced stream of partitioning planes and number of points in the cells of the partition. Compared to previous work, the added value is an improved rate-distortion performance, especially for very low bitrates. The latter are critical for interactive navigation of large 3D point clouds on heterogeneous networked infrastructures.Item A Web-based Visual Analytics Application for Biological Networks(The Eurographics Association, 2020) Krone, Michael; Dräger, Andreas; Cobanoglu, Ebru; Harke, Manuel Otto; Hoene, Miriam; Weigert, Cora; Lehmann, Rainer; Byška, Jan and Jänicke, StefanModern high-throughput methods enable rapidly obtaining transcriptomics data, which includes information about the expression rate of genes. The expression rates are usually given as fold change, which describes the over- or under-expression of each gene. Each gene can be part of one or more biological pathways. A pathway models the interactions between molecules in an organism that lead to a particular chemical change. Consequently, many applications in medical research need to analyze the impact of gene expression changes on the biological pathways of an organism. It allows concluding diseases or other conditions of the organism. We present a web-based visual analytics application that facilitates exploring the network of biological pathways corresponding to a given set of genes. The network is constructed from pathways derived from an external database. Users can interactively zoom and filter the network and get details on demand. Our application is currently work in progress and is developed in close collaboration with medical researchers. In subsequent steps, we strive to add more features, such as the ability to compare data from different individuals or to visualize time series data. Furthermore, we want to extend our application to visualize not just transcriptomics but multi-omics data.Item Cylindrical Transform Slicing of Revolute Parts with Overhangs for Laser Metal Deposition(The Eurographics Association, 2022) Montoya-Zapata, Diego; Moreno, Aitor; Ortiz, Igor; Ruiz-Salguero, Oscar; Posada, Jorge; Posada, Jorge; Serrano, AnaIn the context of Laser Metal Deposition (LMD), temporary support structures are needed to manufacture overhanging features. In order to limit the need for supports, multi-axis machines intervene in the deposition by sequentially repositioning the part. Under multi-axis rotations and translations, slicing and toolpath generation represent significant challenges. Slicing has been partially addressed by authors in multi-axis LMD. However, tool-path generation in multi-axis LMD is rarely touched. One of the reasons is that the required slices for LMD may be strongly non-developable. This fact produces a significant mismatch between the tool-path speeds and other parameters in Parametric space vs. actual Euclidean space. For the particular case of developable slices present in workpieces with cylindrical kernel and overhanging neighborhoods, this manuscript presents a methodology for LMD tool path generation. Our algorithm takes advantage of existing cylindrical iso-radial slicing by generating a path in the (?, z) parameter space and isometrically translating it into the R3 Euclidean space. The presented approach is advantageous because it allows the path-planning of complex structures by using the methods for conventional 2.5-axis AM. Our computer experiments show that the presented approach can be effectively used in manufacturing industrial/mechanical pieces (e.g., spur gears). Future work includes the generation of the machine g-code for actual LMD equipment.Item Projective Augmented Reality in a Museum: Development and Evaluation of an Interactive Application(The Eurographics Association, 2020) Plecher, David A.; Ulschmid, Annalena; Kaiser, Tim; Klinker, Gudrun; Argelaguet, Ferran and McMahan, Ryan and Sugimoto, MakiProjective Augmented Reality (AR) offers exciting new ways of interacting with a museum exhibition. This paper presents such a projective AR application that was developed in cooperation with the ''Museum für Abgüsse Klassischer Bildwerke'' (''Museum of Casts of Classical Statues'') in Munich. It allows visitors to digitally paint a sculpture using a tablet while the result is simultaneously projected onto the real object. A first prototype of the application was tested in regard to usability, integration into the exhibition and its ability to transfer knowledge. The prototype was then improved based on the findings of this first user study and further evaluated in a second, comparative study, this time with a stronger focus on knowledge transfer. Applying regression and the bootstrap method demonstrates an increased effect on learning when using the developed application in comparison to the exhibition method traditionally used by the museum.Item Recognising Specific Foods in MRI Scans Using CNN and Visualisation(The Eurographics Association, 2020) Gardner, Joshua; Al-Maliki, Shatha; Lutton, Évelyne; Boué, François; Vidal, Franck; Ritsos, Panagiotis D. and Xu, KaiThis work is part of an experimental project aiming at understanding the kinetics of human gastric emptying. For this purpose magnetic resonance imaging (MRI) images of the stomach of healthy volunteers have been acquired using a state-of-art scanner with an adapted protocol. The challenge is to follow the stomach content (food) in the data. Frozen garden peas and petits pois have been chosen as experimental proof-of-concept as their shapes are well defined and are not altered in the early stages of digestion. The food recognition is performed as a binary classification implemented using a deep convolutional neural network (CNN). Input hyperparameters, here image size and number of epochs, were exhaustively evaluated to identify the combination of parameters that produces the best classification. The results have been analysed using interactive visualisation. We prove in this paper that advances in computer vision and machine learning can be deployed to automatically label the content of the stomach even when the amount of training data is low and the data imbalanced. Interactive visualisation helps identify the most effective combinations of hyperparameters to maximise accuracy, precision, recall and F1 score, leaving the end-user evaluate the possible trade-off between these metrics. Food recognition in MRI scans through neural network produced an accuracy of 0.97, precision of 0.91, recall of 0.86 and F1 score of 0.89, all close to 1.Item Implicit Modeling of Patient-Specific Aortic Dissections with Elliptic Fourier Descriptors(The Eurographics Association and John Wiley & Sons Ltd., 2021) Mistelbauer, Gabriel; Rössl, Christian; Bäumler, Kathrin; Preim, Bernhard; Fleischmann, Dominik; Borgo, Rita and Marai, G. Elisabeta and Landesberger, Tatiana vonAortic dissection is a life-threatening vascular disease characterized by abrupt formation of a new flow channel (false lumen) within the aortic wall. Survivors of the acute phase remain at high risk for late complications, such as aneurysm formation, rupture, and death. Morphologic features of aortic dissection determine not only treatment strategies in the acute phase (surgical vs. endovascular vs. medical), but also modulate the hemodynamics in the false lumen, ultimately responsible for late complications. Accurate description of the true and false lumen, any communications across the dissection membrane separating the two lumina, and blood supply from each lumen to aortic branch vessels is critical for risk prediction. Patient-specific surface representations are also a prerequisite for hemodynamic simulations, but currently require time-consuming manual segmentation of CT data. We present an aortic dissection cross-sectional model that captures the varying aortic anatomy, allowing for reliable measurements and creation of high-quality surface representations. In contrast to the traditional spline-based cross-sectional model, we employ elliptic Fourier descriptors, which allows users to control the accuracy of the cross-sectional contour of a flow channel. We demonstrate (i) how our approach can solve the requirements for generating surface and wall representations of the flow channels, (ii) how any number of communications between flow channels can be specified in a consistent manner, and (iii) how well branches connected to the respective flow channels are handled. Finally, we discuss how our approach is a step forward to an automated generation of surface models for aortic dissections from raw 3D imaging segmentation masks.Item Fabricatable 90° Pop-ups: Interactive Transformation of a 3D Model into a Pop-up Structure(The Eurographics Association and John Wiley & Sons Ltd., 2023) Fujikawa, Junpei; Ijiri, Takashi; Chaine, Raphaëlle; Deng, Zhigang; Kim, Min H.Ninety-degree pop-ups are a type of papercraft on which a three-dimensional (3D) structure pops up when the angle of the base fold is 90°. They are fabricated by cutting and creasing a single sheet of paper. Traditional 90° pop-ups are limited to 3D shapes only comprising planar shapes because they are made of paper. In this paper, we present novel pop-ups, fabricatable 90° pop-ups that employ the 90° pop-up mechanism, consist of components with curved shapes, and can be fabricatable using a 3D printer. We propose a method for converting a 3D model into a fabricatable 90° pop-up. The user first interactively designs a layout of pop-up components, and the system automatically deforms the components using the 3D model. Because the generated pop-ups contain necessary cuts and folds, no additional assembly process is required. To demonstrate the feasibility of the proposed method, we designed and fabricated various 90° pop-ups using a 3D printer.Item Immersive WebXR Data Visualisation Tool(The Eurographics Association, 2023) Ogbonda, Ebube Glory; Vangorp, Peter; Hunter, DavidThis paper presents a study of a WebXR data visualisation tool designed for the immersive exploration of complex datasets in a 3D environment. The application developed using AFrame, D3.js, and JavaScript enables an interactive, device-agnostic platform compatible with various devices and systems. A user study is proposed to assess the tool's usability, user experience, and mental workload using the NASA Task Load Index (NASA TLX). The evaluation is planned to employ questionnaires, task completion times, and open-ended questions to gather feedback and insights. The anticipated results aim to provide insights into the effectiveness of the application in supporting users in understanding and extracting insights from complex data while delivering an engaging and intuitive experience. Future work will refine and expand the tool's capabilities by exploring interaction guidance, visualisation layout optimisation, and long-term user experience assessment. This research contributes to the growing field of immersive data visualisation and informs future tool design.