EG2019

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https://diglib.eg.org/handle/10.2312/2632746

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Rethinking Texture Mapping
(The Eurographics Association and John Wiley & Sons Ltd., 2019) Yuksel, Cem; Lefebvre, Sylvain; Tarini, Marco; Giachetti, Andrea and Rushmeyer, Holly
The intrinsic problems of texture mapping, regarding its difficulties in content creation and the visual artifacts it causes in rendering, are well-known, but often considered unavoidable. In this state of the art report, we discuss various radically different ways to rethink texture mapping that have been proposed over the decades, each offering different advantages and trade-offs. We provide a brief description of each alternative texturing method along with an evaluation of its strengths and weaknesses in terms of applicability, usability, filtering quality, performance, and potential implementation related challenges.
Investigating Different Augmented Reality Approaches in Circuit Assembly: a User Study
(The Eurographics Association, 2019) Marques, Bernardo; Esteves, Rafael; Alves, João; Ferreira, Carlos; Dias, Paulo; Santos, Beatriz Sousa; Cignoni, Paolo and Miguel, Eder
Augmented Reality (AR) has been considered as having great potential in assisting performance and training of complex tasks. Assembling electronic circuits is such a task, since many errors may occur, as wrong choice or positioning of components or incorrect wiring and thus using AR approaches may be beneficial. This paper describes a controlled experiment aimed at comparing usability and acceptance of two AR-based approaches (one based on a single device and another approach using two interconnected devices), with a traditional approach using a paper manual in the assembly of an electronic circuit. Participants were significantly faster and made fewer errors while using the AR approaches, and most preferred the multi-device approach.
Hybrid Function Representation with Distance Properties
(The Eurographics Association, 2019) Tereshin, Alexander; Adzhiev, Valery; Fryazinov, Oleg; Pasko, Alexander; Cignoni, Paolo and Miguel, Eder
This paper describes a novel framework allowing for a hybrid representation of heterogeneous objects. We consider advantages and drawbacks of the conventional representations based on scalar fields of different kinds. The main result is introducing a hybrid representation called Hybrid Function Representation (HFRep) that preserves the advantages of the Function Representation (FRep) and Signed Distance Fields (SDFs) without their drawbacks. This new representation allows for obtaining a continuous smooth distance field in the Euclidean space for the FRep. We present the mathematical basics for our approach that uses the Discrete Distance Transform (DDT) and a step-function. The procedure for generation HFRep using continuous interpolation and smoothing techniques are also described. A few examples show how the approach works in practice.
How to Write a Visualization Survey Paper: A Starting Point
(The Eurographics Association, 2019) McNabb, Liam; Laramee, Robert S.; Tarini, Marco and Galin, Eric
This paper attempts to explain the mechanics of writing a survey paper in data visualization or visual analytics. It serves as a useful starting point for those who have never written a survey paper or have very little experience. A literature review or survey paper is often considered the starting point of a PhD candidate's scientific degree. However, there are no dedicated papers that focus on guidelines for the planning or writing of a survey paper or literature review in visualization or visual analytics. We provide guidelines and our recommendations for a foundational structure on which to build a survey paper, whilst also considering intermediate goals, and offer helpful advice to improve the survey process and literature analysis. The result is a useful starting point for those wishing to write a survey paper or state-of-the-art (STAR) review in visualization or visual analytics. The guidelines and recommendations we make can also be generalized to other areas of computing and science. An abstract is a required feature of a survey paper and should identity the topic of the literature review. A good abstract addresses why the given topic is interesting and why it is helpful. A good abstract features the following elements: (1) topic introduction, (2) the motivation, (3) the goal of the review, and the benefits the review provides to the reader. A good literature survey offers a helpful classification of the literature, mature areas of research, and open, unsolved problems in visualization or visual analytics.
The Effects of Adaptive Synchronization on Performance and Experience in Gameplay
(The Eurographics Association, 2019) Watson, Benjamin; Gavane, Ajinkya; Shrivastava, Rachit; Fusiello, Andrea and Bimber, Oliver
As graphics (GPU) hardware has improved, fixed refresh rate displays became a significant throttle on graphics performance. GPU and display manufacturers therefore introduced adaptive synchronization (Async), which allows displays to adaptively synchronize to GPUs, avoiding rendering stalls and improving frame rate mean and variation. This research is a first experimental examination of the effects of Async on the experience of dedicated (but not professional) gamers. Participants played a first-person shooter (FPS) game, both with Async on and with Async off. After each game session, we assessed participant emotional state and gaming performance. We learned that at least for this popular FPS, Async can improve gaming performance, and may also benefit experience. We also found that Async has intriguing relationships to game familiarity and years of gameplay that merit additional investigation. Further research should examine these relationships, as well as Async's effects in systems with higher frame rates.
Automatic Environment Map Registration
(The Eurographics Association, 2019) Larvy, Ulysse; Loscos, Céline; Chrysanthou, Yiorgos; Cignoni, Paolo and Miguel, Eder
In this paper, a method to automatically register an environment map (EM) around a local scene is presented. In the literature, this step is most of the time manually processed by a user. However, it is an essential step when lighting and/or background coherence is needed. We present a method to find the coherent spatial organization between a main light source present in the EM and a couple object/shadow in a local scene. We automatically recover the EM orientation which corresponds to the local scene illumination. We proceed to a 3D representation of the scene using the EM mapped on a hemisphere as a background scene, a simplified geometry description of the reference object and its shadow outline. As a first step, we compute a projection of the main object shadow to compare it against the real acquired shadow. In a second step, we minimize a metric based on Euclidean Distance Transform (EDT), to compare both shadows and to recover the EM orientation. We demonstrate that we can automatically find rotation and scaling parameters that position in a coherent manner the background around a local scene.
A Projection Mapping System onto a Human Body for Medical Applications
(The Eurographics Association, 2019) Fukuhara, Ryo; Kaneda, Kazufumi; Tamaki, Toru; Raytchev, Bisser; Higaki, Toru; Nishimoto, Soh; Sotsuka, Yohei; Fusiello, Andrea and Bimber, Oliver
In breast reconstructive surgery where patient's abdominal fat and blood vessels are transplanted to the breast, it is very important to identify the course of the blood vessels inside the abdomen. In this paper, we propose a system for projecting blood vessels extracted from computer tomography angiography (CTA) on a patient's abdominal surface to support the breast reconstructive surgery. The proposed system detects the position and orientation of a projector automatically using an image captured by a camera mounted with the projector and is able to project the exact course of the blood vessels onto an abdominal skin from an arbitrary direction. An experiment using an abdominal model fabricated from patient's CTA data with a 3D printer demonstrates the usefulness of the proposed system.
Enhanced Reconstruction of Architectural Wall Surfaces for 3D Building Models
(The Eurographics Association, 2019) Michailidis, Georgios-Tsampikos; Pajarola, Renato; Fusiello, Andrea and Bimber, Oliver
The reconstruction of architectural structures from 3D building models is a challenging task and a lot of research has been done in recent years. However, most of this work is focused mainly on reconstructing accurately the architectural shape of interiors rather than the fine architectural details, such as the wall elements (e.g. windows and doors). We focus specifically on this problem and propose a method that extends current solutions to reconstruct accurately severely occluded wall surfaces.
Assessing Graphic Designers' Learning Style Profile to Improve Creative Coding Courses
(The Eurographics Association, 2019) Hansen, Stig Møller; Tarini, Marco and Galin, Eric
This study aimed at assessing graphic design students' preferences for learning to help design school educators teaching Creative Coding programming courses adapt their teaching style to account for the way their students learn. The Felder- Soloman Index of Learning Styles (ILS©) was administered to 77 bachelor-level graphic design students. Compared to students in technical fields, the graphic design students differed by being considerably more intuitive, with an increased preference for active and visual learning. Based on these findings, specific recommendations and issues for educators to consider are presented.
Font Specificity
(The Eurographics Association, 2019) Power, Luther; Lau, Manfred; Cignoni, Paolo and Miguel, Eder
We explore the concept of ''image specificity'' for fonts and introduce the notion of ''font specificity''. The idea is that a font that elicits consistent descriptions from different people are more ''specific''. We collect specificity-based data for fonts where participants are given each font and asked to describe it with words. We then analyze the data and characterize the qualitative features that make a font ''specific''. Finally, we show that the notion of font specificity can be learned and demonstrate some specificity-guided applications.
Schelling Meshes
(The Eurographics Association, 2019) Power, Luther; Lau, Manfred; Cignoni, Paolo and Miguel, Eder
The concept of ''Schelling points'' on 3D shapes has been explored for points on the surface of a 3D mesh. In this paper, we introduce the notion of ''Schelling meshes'' which extends the Schelling concept to 3D meshes as a whole themselves. We collect Schelling-based data for meshes where participants are given a group of shapes and asked to choose those with the aim of matching with what they expect others to choose. We analyze the data by computing the Schelling frequency of each shape and characterizing the qualitative features that make a shape ''Schelling''. We show that the Schelling frequencies can be learned and demonstrate Schelling-guided shape applications.
Area Lights in Signed Distance Function Scenes
(The Eurographics Association, 2019) Bán, Róbert; Bálint, Csaba; Valasek, Gábor; Cignoni, Paolo and Miguel, Eder
This paper presents two algorithms to incorporate spherical and general area lights into scenes defined by signed distance functions. The first algorithm employs an efficient approximation to the contribution of spherical lights to direct illumination and renders them at real-time rates. The second algorithm is of superior quality at a higher computational cost which is better suited for interactive rates. Our results are compared to both real-time soft shadow algorithms and a ground truth obtained by Monte Carlo integration. We show in these comparisons that our real-time solution computes more accurate shadows while the more demanding variant outperforms Monte Carlo integration at the expense of accuracy.
A Preliminary Analysis of Methods for Curvature Estimation on Surfaces With Local Reliefs
(The Eurographics Association, 2019) Moscoso Thompson, Elia; Biasotti, Silvia; Cignoni, Paolo and Miguel, Eder
Curvature estimation is very popular in geometry processing for the analysis of local surface variations. Despite the large number of methods, no quantitative nor qualitative studies have been conducted for a comparative analysis of the different algorithms on surfaces with small geometric variations, such as chiselled or relief surfaces. In this work we compare eight curvature estimation methods that are commonly adopted by the computer graphics community on a number of triangle meshes derived from scans of surfaces with local reliefs.
Perceptual Characteristics by Motion Style Category
(The Eurographics Association, 2019) Kim, Hye Ji; Lee, Sung-Hee; Cignoni, Paolo and Miguel, Eder
Motion style is important as it characterizes a motion by expressing the context of the motion such as emotion and personality. Yet, the perception and interpretation of motion styles is subjective and may vary greatly from person to person. This paper investigates the perceptual characteristics of motion styles for a wide range of styles. After categorizing the motion styles, we perform user studies to examine the diversity of interpretations of motion styles and the association level between style motions and their corresponding text descriptions. Our study shows that motion styles have different interpretation diversity and association level according to their categories. We discuss the implications of these findings and recommend a method of labeling or describing motion styles.
Voxelizing Light-Field Recordings
(The Eurographics Association, 2019) Schedl, David; Kurmi, Indrajit; Bimber, Oliver; Fusiello, Andrea and Bimber, Oliver
Light fields are an emerging image-based technique that support free viewpoint navigation of recorded scenes as demanded in several recent applications (e.g., Virtual Reality). Pure image-based representations, however quickly become inefficient, as a large number of images are required to be captured, stored, and processed. Geometric scene representations require less storage and are more efficient to render. Geometry reconstruction, however, is unreliable and might fail for complex scene parts. Furthermore, view-dependent effects that are preserved with light fields are lost in pure geometry-based techniques. Therefore, we propose a hybrid representation and rendering scheme for recorded dense light fields: we extract isotropic scene regions and represent them by voxels, while the remaining areas are represented as sparse light field. In comparison to dense light fields, storage demands are reduced while visual quality is sustained.
Visual-auditory Representation and Analysis of Molecular Scalar Fields
(The Eurographics Association, 2019) Malikova, Evgeniya; Adzhiev, Valery; Fryazinov, Oleg; Pasko, Alexander; Fusiello, Andrea and Bimber, Oliver
The work deals with a visual-auditory representation and an analysis of static and dynamic continuous scalar fields.We propose a general approach and give examples of dynamic and static objects representations related to molecular data simulations. We describe the practical application and demonstrate how the approach may help to track geometrical features.
A Review of Digital Terrain Modeling
(The Eurographics Association and John Wiley & Sons Ltd., 2019) Galin, Eric; Guérin, Eric; Peytavie, Adrien; Cordonnier, Guillaume; Cani, Marie-Paule; Benes, Bedrich; Gain, James; Giachetti, Andrea and Rushmeyer, Holly
Terrains are a crucial component of three-dimensional scenes and are present in many Computer Graphics applications. Terrain modeling methods focus on capturing landforms in all their intricate detail, including eroded valleys arising from the interplay of varied phenomena, dendritic mountain ranges, and complex river networks. Set against this visual complexity is the need for user control over terrain features, without which designers are unable to adequately express their artistic intent. This article provides an overview of current terrain modeling and authoring techniques, organized according to three categories: procedural modeling, physically-based simulation of erosion and land formation processes, and example-based methods driven by scanned terrain data. We compare and contrast these techniques according to several criteria, specifically: the variety of achievable landforms; realism from both a perceptual and geomorphological perspective; issues of scale in terms of terrain extent and sampling precision; the different interaction metaphors and attendant forms of user-control, and computation and memory performance. We conclude with an in-depth discussion of possible research directions and outstanding technical and scientific challenges.
Visualization of Large Point Cloud in Unity
(The Eurographics Association, 2019) Santana Núñez, José Miguel; Trujillo, Agustin; Ortega, Sebastián; Fusiello, Andrea and Bimber, Oliver
Large point cloud rendering has become a very relevant topic on 3D graphics as scanners and other sources of 3D point data are nowadays available to companies and the general public. In this project, we propose an implementation of a point cloud viewer, designed for the full-detail visualization of virtually unlimited point clouds for their inspection on short ranges. This work presents the data structure and the LoD technique to achieve a real-time rendering of the model, making emphasis on the details of an initial prototype based on Unity.
A Validation Tool For Improving Semantic Segmentation of Complex Natural Structures
(The Eurographics Association, 2019) Pavoni, Gaia; Corsini, Massimiliano; Palma, Marco; Scopigno, Roberto; Cignoni, Paolo and Miguel, Eder
The automatic recognition of natural structures is a challenging task in the supervised learning field. Complex morphologies are difficult to detect both from the networks, that may suffer from generalization issues, and from human operators, affecting the consistency of training datasets. The task of manual annotating biological structures is not comparable to a generic task of detecting an object (a car, a cat, or a flower) within an image. Biological structures are more similar to textures, and specimen borders exhibit intricate shapes. In this specific context, manual labelling is very sensitive to human error. The interactive validation of the predictions is a valuable resource to improve the network performance and address the inaccuracy caused by the lack of annotation consistency of human operators reported in literature. The proposed tool, inspired by the Yes/No Answer paradigm, integrates the semantic segmentation results coming from a CNN with the previous human labeling, allowing a more accurate annotation of thousands of instances in a short time. At the end of the validation, it is possible to obtain corrected statistics or export the integrated dataset and re-train the network.
Cytosplore: Interactive Visual Single-Cell Profiling of the Immune System
(The Eurographics Association, 2019) Höllt, Thomas; Pezzotti, Nicola; van Unen, Vincent; Li, Na; Koning, Frits; Eisemann, Elmar; Lelieveldt, Boudewijn P. F.; Vilanova, Anna; Bruckner, Stefan and Oeltze-Jafra, Steffen
Recent advances in single-cell acquisition technology have led to a shift towards single-cell analysis in many fields of biology. In immunology, detailed knowledge of the cellular composition is of interest, as it can be the cause of deregulated immune responses, which cause diseases. Similarly, vaccination is based on triggering proper immune responses; however, many vaccines are ineffective or only work properly in a subset of those who are vaccinated. Identifying differences in the cellular composition of the immune system in such cases can lead to more precise treatment. Cytosplore is an integrated, interactive visual analysis framework for the exploration of large single-cell datasets. We have developed Cytosplore in close collaboration with immunology researchers and several partners use the software in their daily workflow. Cytosplore enables efficient data analysis and has led to several discoveries alongside high-impact publications.

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