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Item Automating Visualization Quality Assessment: a Case Study in Higher Education(The Eurographics Association, 2021) Holliman, Nicolas S.; Xu, Kai and Turner, MartinWe present a case study in the use of machine+human mixed intelligence for visualization quality assessment, applying automated visualization quality metrics to support the human assessment of data visualizations produced as coursework by students taking higher education courses. A set of image informatics algorithms including edge congestion, visual saliency and colour analysis generate machine analysis of student visualizations. The insight from the image informatics outputs has proved helpful for the marker in assessing the work and is also provided to the students as part of a written report on their work. Student and external reviewer comments suggest that the addition of the image informatics outputs to the standard feedback document was a positive step. We review the ethical challenges of working with assessment data and of automating assessment processes.Item Visual Analysis of Popping in Progressive Visualization(The Eurographics Association, 2021) Waterink, Ethan; Kosinka, Jiri; Frey, Steffen; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà , EmanueleProgressive visualization allows users to examine intermediate results while they are further refined in the background. This makes them increasingly popular when dealing with large data and computationally expensive tasks. The characteristics of how preliminary visualizations evolve over time are crucial for efficient analysis; in particular unexpected disruptive changes between iterations can significantly hamper the user experience. This paper proposes a visualization framework to analyze the refinement behavior of progressive visualization. We particularly focus on sudden significant changes between the iterations, which we denote as popping artifacts, in reference to undesirable visual effects in the context of level of detail representations in computer graphics. Our visualization approach conveys where in image space and when during the refinement popping artifacts occur. It allows to compare across different runs of stochastic processes, and supports parameter studies for gaining further insights and tuning the algorithms under consideration. We demonstrate the application of our framework and its effectiveness via two diverse use cases with underlying stochastic processes: adaptive image space sampling, and the generation of grid layouts.Item 3D Visualisations Should Not be Displayed Alone - Encouraging a Need for Multivocality in Visualisation(The Eurographics Association, 2021) Roberts, Jonathan C.; Mearman, Joseph W.; Butcher, Peter W. S.; Al-Maneea, Hayder M.; Ritsos, Panagiotis D.; Xu, Kai and Turner, MartinWe believe that 3D visualisations should not be used alone; by coincidentally displaying alternative views the user can gain the best understanding of all situations. The different presentations signify manifold meanings and afford different tasks. Natural 3D worlds implicitly tell many stories. For instance, walking into a living room, seeing the TV, types of magazines, pictures on the wall, tells us much about the occupiers: their occupation, standards of living, taste in design, whether they have kids, and so on. How can we similarly create rich and diverse 3D visualisation presentations? How can we create visualisations that allow people to understand different stories from the data? In a multivariate 2D visualisation a developer may coordinate and link many views together to provide exploratory visualisation functionality. But how can this be achieved in 3D and in immersive visualisations? Different visualisation types, each have specific uses, and each has the potential to tell or evoke a different story. Through several use-cases, we discuss challenges of 3D visualisation, and present our argument for concurrent and coordinated visualisations of alternative styles, and encourage developers to consider using alternative representations with any 3D view, even if that view is displayed in a virtual, augmented or mixed reality setup.Item Learning Activities in Colours and Rainbows for Programming Skill Development(The Eurographics Association, 2021) Roberts, Jonathan C.; Xu, Kai and Turner, MartinWe present how we have created a series of bilingual (English and Welsh) STEM activities focusing on rainbows, colours, light and optical effects. The activities were motivated by the many rainbows that appeared in windows in the UK, in support of the National Health Service at the start of the coronavirus pandemic. Rainbows are hopeful and are very fitting to be used as a positive iconic image at a time of much uncertainty. In this paper we explain how we have developed and organised the activities, focusing on colours, computer graphics and computer programming. Each lesson contains one or more activities, which enable people to take an active role in their learning.We have carefully prepared and organised several processes to guide academic colleagues to create and publish different activities in the theme. Which means that the activities appear similarly structured, can be categorised and searched in a consistent way. This structure can act as a blueprint for others to follow and apply to develop their own online course. The activities incrementally take people through learning about colour, rainbows, planning what to program, design and strategies to create colourful pictures using simple computer graphics principles based in processing.org.Item SlowDeepFood: a Food Computing Framework for Regional Gastronomy(The Eurographics Association, 2021) Gilal, Nauman Ullah; Al-Thelaya, Khaled; Schneider, Jens; She, James; Agus, Marco; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà , EmanueleFood computing recently emerged as a stand-alone research field, in which artificial intelligence, deep learning, and data science methodologies are applied to the various stages of food production pipelines. Food computing may help end-users in maintaining healthy and nutritious diets by alerting of high caloric dishes and/or dishes containing allergens. A backbone for such applications, and a major challenge, is the automated recognition of food by means of computer vision. It is therefore no surprise that researchers have compiled various food data sets and paired them with well-performing deep learning architecture to perform said automatic classification. However, local cuisines are tied to specific geographic origins and are woefully underrepresented in most existing data sets. This leads to a clear gap when it comes to food computing on regional and traditional dishes. While one might argue that standardized data sets of world cuisine cover the majority of applications, such a stance would neglect systematic biases in data collection. It would also be at odds with recent initiatives such as SlowFood, seeking to support local food traditions and to preserve local contributions to the global variation of food items. To help preserve such local influences, we thus present a full end-to-end food computing network that is able to: (i) create custom image data sets semi-automatically that represent traditional dishes; (ii) train custom classification models based on the EfficientNet family using transfer learning; (iii) deploy the resulting models in mobile applications for real-time inference of food images acquired through smart phone cameras. We not only assess the performance of the proposed deep learning architecture on standard food data sets (e.g., our model achieves 91:91% accuracy on ETH’'s Food-101), but also demonstrate the performance of our models on our own, custom data sets comprising local cuisine, such as the Pizza-Styles data set and GCC-30. The former comprises 14 categories of pizza styles, whereas the latter contains 30 Middle Eastern dishes from the Gulf Cooperation Council members.Item RECCS: Real-Time Camera Control for Particle Systems(The Eurographics Association, 2021) Köster, Marcel; Groß, Julian; Krüger, Antonio; Xu, Kai and Turner, MartinInteractive exploration and analysis of large 3D particle systems, consisting of hundreds of thousands of particles, are common tasks in the field of scientific and information visualization. These steps typically involve selection and camera-update operations in order to reveal patterns or to focus on subsets. Moreover, if a certain region is known to be potentially interesting or a selection has been made, the user will have to choose a proper camera setup to investigate further. However, such a setup is typically chosen in a way that the interesting region is in the center of the screen. Unfortunately, it still needs to show important characteristics of the selected subset and has the least amount of occlusions with respect to other particles but shows enough context information in terms of non-selected particles. In this paper, we propose a novel method for real-time camera control in 3D particle systems that fulfills these requirements. It is based on a user and/or domain-specific evaluation heuristic and parallel optimization algorithm that is designed for Graphics-Processing Units (GPUs). In addition, our approach takes only several milliseconds to complete, even on the aforementioned large datasets while consuming only a few megabytes in global GPU memory in general. This is due the fact that we are able to reduce the processing complexity significantly using screenspace information and the excessive use of fast on-chip shared memory. This allows it to be seamlessly integrated into modern visualization systems that need real-time feedback while processing large particle-based datasets.Item ProtoSketchAR: Prototyping in Augmented Reality via Sketchings(The Eurographics Association, 2021) Arriu, Simone; Cherchi, Gianmarco; Spano, Lucio Davide; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà , EmanuelePrototyping is a widely used technique in the early stages of system design, and it is an essential part of a new product development process. During this phase, designers identify the main functionalities, concepts and contents of the system without creating a fully functional system. This paper aims to discuss the development of ProtoSketchAR, a tool enabling Augmented Reality (AR) prototyping by sketching. The application has different interaction modes, depending on the performed functionality. Basically, it is possible to create 2D/3D sketches to be placed in the real environment and to manipulate them. These functionalities allow the creation of virtual elements that can be used to prototype screens of AR applications. The application is web-based so that it can be run on any device with a compatible AR browser, regardless of the operating system used.Item ISSIGraph: An Open Source Multi-platform C++ Tool for Rapid 2D/3D Wireframe Sketching(The Eurographics Association, 2021) Jiménez de Parga, Carlos; ; Ortega, Lidia M. and Chica, AntonioRapid sketch modelling and Computer-Aided Design (CAD) initiation are increasingly demanded activities in the creative and educational areas. For this reason, this paper presents a cross-platform C++ toolkit with the aim to facilitate the illustration of technical concepts in a fast way using basic quadric objects, Bézier and NURBS surfaces with a wireframe representation. This tool was designed using Software Engineering principles guided by a basic Rational Unified Process (RUP) methodology with the application of the Unified Modelling Language (UML). This tool perfectly works in all computers with very elemental 3D graphics hardware and with OpenGL support. The resulting benchmarks demonstrate that ISSIGraph has a very small CPU footprint that make it suitable for any platform. As a consequence, this application is well suited for rapid 2D/3D project sketching in the creative and engineering fields, as well as an initiation to CAD techniques for students and computer fans.Item Remote Volume Rendering with a Decoupled, Ray-Traced Display Phase(The Eurographics Association, 2021) Zellmann, Stefan; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà , EmanueleWe propose an image warping-based remote rendering technique for volumes that decouples the rendering and display phases. For that we build on prior work where we sample the volume on the client using ray casting and reconstruct z-values based on heuristics. Color and depth buffers are then sent to the client, which reuses this depth image as a stand-in for subsequent frames by warping it to reflect the current camera position and orientation until new data was received from the server. The extension we propose in this work represents the depth pixels as spheres and ray traces them on the client side. In contrast to the reference method, this representation adapts the footprint of the depth pixels to the distance to the camera origin, which is more effective at hiding warping artifacts, particularly when applied to volumetric data sets.Item Design Guidelines for Virtual Neurological Procedures(The Eurographics Association, 2021) Mancosu, Mattia S.; Czanner, Silvester; Xu, Kai and Turner, MartinThe role of technology has become more and more preponderant for educational purposes in schools, in universities and for training. It is also applied in healthcare and neurology training thanks to the proven effectiveness and the rising demand inside hospitals and medical schools. The necessity to outline design guidelines is increasing hand to hand with the aforementioned phenomenon. In this paper we will discuss some key aspects of a healthcare teaching application such as the fidelity of the learning environment, the target platform of the application with a particular focus on Virtual Reality, and the learning strategies that can be implemented within the program. We will also illustrate some results of our stroke assessment training application, where we proved the effectiveness of the proper implementation of some design aspects that we addressed inside the guidelines section.