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Item Statistical Analysis of Parallel Data Uploading using OpenGL(The Eurographics Association, 2019) Wiedemann, Markus; Kranzlmüller, Dieter; Childs, Hank and Frey, SteffenModern real-time visualizations of large-scale datasets require constant high frame rates while their datasets might exceed the available graphics memory. This requires sophisticated upload strategies from host memory to the memory of the graphics cards. A possible solution uses outsourcing of all data uploads onto concurrent threads and disconnecting prohibitive data dependencies. OpenGL provides a variety of functions and parameters but not all allow minimal interference on rendering. In this work, we present a thorough and statistically sound analysis of various effects introduced by choosing different input parameters, such as size, partitioning and number of threads for uploading, as well as combinations of buffer usage hints and uploading functions. This approach provides insight into the problem and offers a basis for future optimizations.Item A Multifragment Renderer for Material Aging Visualization(The Eurographics Association, 2018) Adamopoulos, Georgios; Moutafidou, Anastasia; Drosou, Anastasios; Tzovaras, Dimitrios; Fudos, Ioannis; Jain, Eakta and Kosinka, JirÃPeople involved in curatorial work and in preservation/conservation tasks need to understand exactly the nature of aging and to prevent it with minimal preservation work. In this scenario, it is of extreme importance to have tools to produce and visualize digital representations and models of visual surface appearance and material properties, to help the scientist understand how they evolve over time and under particular environmental conditions. We report on the development of a multifragment renderer for visualizing and combining the results of simulated aging of artwork objects. Several natural aging processes manifest themselves through change of color, fading, deformations or cracks. Furthermore, changes in the materials underneath the visible layers may be detected or simulated.Item Learning Physically Based Humanoid Climbing Movements(The Eurographics Association and John Wiley & Sons Ltd., 2018) Naderi, Kourosh; Babadi, Amin; Hämäläinen, Perttu; Thuerey, Nils and Beeler, ThaboWe propose a novel learning-based solution for motion planning of physically-based humanoid climbing that allows for fast and robust planning of complex climbing strategies and movements, including extreme movements such as jumping. Similar to recent previous work, we combine a high-level graph-based path planner with low-level sampling-based optimization of climbing moves. We contribute through showing that neural network models of move success probability, effortfulness, and control policy can make both the high-level and low-level components more efficient and robust. The models can be trained through random simulation practice without any data. The models also eliminate the need for laboriously hand-tuned heuristics for graph search. As a result, we are able to efficiently synthesize climbing sequences involving dynamic leaps and one-hand swings, i.e. there are no limits to the movement complexity or the number of limbs allowed to move simultaneously. Our supplemental video also provides some comparisons between our AI climber and a real human climber.Item Extreme Feature Regions for Image Matching(The Eurographics Association, 2018) Fan, Baijiang; Rao, Yunbo; Pu, Jiansu; Deng, Jianhua; Fu, Hongbo and Ghosh, Abhijeet and Kopf, JohannesExtreme feature regions are increasingly critical for many image matching applications on affine image-pairs. In this paper, we focus on the time-consumption and accuracy of using extreme feature regions to do the affine-invariant image matching. Specifically, we proposed novel image matching algorithm using three types of critical points in Morse theory to calculate precise extreme feature regions. Furthermore, Random Sample Consensus (RANSAC) method is used to eliminate the features of complex background, and improve the accuracy of the extreme feature regions. Moreover, the saddle regions is used to calculate the covariance matrix for image matching. Extensive experiments on several benchmark image matching databases validate the superiority of the proposed approaches over many recently proposed affine-invariant SIFT algorithms.Item A Massively Parallel CUDA Algorithm to Compute and Visualize the Solvent Excluded Surface for Dynamic Molecular Data(The Eurographics Association, 2019) Schäfer, Marco; Krone, Michael; Byska, Jan and Krone, Michael and Sommer, BjörnThe interactive visualization of molecular surfaces can help users to understand the dynamic behavior of proteins in molecular dynamics simulations. These simulations play an important role in biochemical and pharmaceutical research, e.g. in drug design. The efficient calculation of molecular surfaces in a fast and memory-saving way is a challenging task. For example, to gain a detailed understanding of complex diseases like Alzheimer, conformational changes and spatial interactions between molecules have to be investigated. Molecular surfaces, such as Solvent Excluded Surfaces (SES), are instrumental for identifying structures such as tunnels or cavities that critically influence transport processes and docking events, which might induce enzymatic reactions. Therefore, we developed a highly parallelized algorithm that exploits the massive computing power of modern graphics hardware. Our analytical algorithm is suitable for the real-time computation of dynamic SES based on many time steps, as it runs interactively on a single consumer GPU for more than 20 k atoms.Item Semantic Reconstruction: Reconstruction of Semantically Segmented 3D Meshes via Volumetric Semantic Fusion(The Eurographics Association and John Wiley & Sons Ltd., 2018) Jeon, Junho; Jung, Jinwoong; Kim, Jungeon; Lee, Seungyong; Fu, Hongbo and Ghosh, Abhijeet and Kopf, JohannesSemantic segmentation partitions a given image or 3D model of a scene into semantically meaning parts and assigns predetermined labels to the parts. With well-established datasets, deep networks have been successfully used for semantic segmentation of RGB and RGB-D images. On the other hand, due to the lack of annotated large-scale 3D datasets, semantic segmentation for 3D scenes has not yet been much addressed with deep learning. In this paper, we present a novel framework for generating semantically segmented triangular meshes of reconstructed 3D indoor scenes using volumetric semantic fusion in the reconstruction process. Our method integrates the results of CNN-based 2D semantic segmentation that is applied to the RGB-D stream used for dense surface reconstruction. To reduce the artifacts from noise and uncertainty of single-view semantic segmentation, we introduce adaptive integration for the volumetric semantic fusion and CRF-based semantic label regularization. With these methods, our framework can easily generate a high-quality triangular mesh of the reconstructed 3D scene with dense (i.e., per-vertex) semantic labels. Extensive experiments demonstrate that our semantic segmentation results of 3D scenes achieves the state-of-the-art performance compared to the previous voxel-based and point cloud-based methods.Item Towards Biomechanically and Visually Plausible Volumetric Cutting Simulation of Deformable Bodies(The Eurographics Association, 2019) Qian, Yinling; Huang, Wenbin; Si, Weixin; Liao, Xiangyun; Wang, Qiong; Heng, Pheng-Ann; Lee, Jehee and Theobalt, Christian and Wetzstein, GordonDue to the simplicity and high efficiency, composited finite element method(CFEM) based virtual cutting attracted much attention in the field of virtual surgery in recent years. Even great progress has been made in volumetric cutting of deformable bodies, there are still several open problems restricting its applications in practical surgical simulator. First among them is cutting fracture modelling. Recent methods would produce cutting surface immediately after an intersection between the cutting plane and the object. But in real cutting, biological tissue would first deform under the external force induced by scalpel and then fracture occurs when the stress exceeds a threshold. Secondly, it's computation-intensive to reconstruct cutting surface highly consistent with the scalpel trajectory, since reconstructed cutting surface in CFEM-based virtual cutting simulation is grid-dependent and the accuracy of cutting surface is proportional to the grid resolution. This paper propose a virtual cutting method based on CFEM which can effectively simulate cutting fracture in a biomechanically and visually plausible way and generate cutting surface which is consistent with the scalpel trajectory with a low resolution finite element grid. We model this realistic cutting as a deformation-fracture repeating process. In deformation stage, the object will deform along with the scalpel motion, while in the fracture stage cutting happens and a cutting surface will be generated from the scalpel trajectory. A delayed fracturing criteria is proposed to determine when and how the cutting fracture occurs and an influence domain adaptation method is employed to generate accurate cutting surface in both procedures of deformation and fracture. Experiments show that our method can realistically simulate volumetric cutting of deformable bodies and efficiently generate accurate cutting surface thus facilitating interactive applications.Item 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, EderCurvature 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.Item Pairwise Matching of Stone Tools Based on Flake-Surface Contour Points and Normals(The Eurographics Association, 2017) Xi, Yang; Matsuyama, Katsutsugu; Konno, Kouichi; Tobias Schreck and Tim Weyrich and Robert Sablatnig and Benjamin StularStone tools constitute the main artifacts facilitating archaeological research of the Paleolithic era. The reassembly of stone tools is the most important research work for analyzing human activities of that period. In recent decades, large numbers of methods have been presented to solve various registration or matching problems for point clouds; however, few methods have been successfully applied to the matching of flakes, a type of stone tool. Therefore, we propose a new matching method for studying stone tools to improve archaeological research. Our method processes pairwise matching of stone tools based on contour points and mean normals of regions on all flake surfaces, according to the characteristics of the flake models. The sample experiments conducted in this study indicate that our new method achieves superior matching results for flakes, compared with the existing methods.Item Study of the Influence of User Characteristics on the Virtual Reality Presence(The Eurographics Association, 2018) Mayor, Jesús; Sánchez, Alberto; Raya, Laura; GarcÃa-Fernández, Ignacio and Ureña, CarlosIn recent years, virtual reality has grown a lot in different areas of application, including ludic, social and research, being used by a large and growing number of users with different profiles. Presence is one of the most distinctive and important features of a virtual reality experience. The aim of this article is to study the most suitable areas of application for users and to analyze the influence of different characteristics of the user's profile in the perceived presence. We have tested the interest applications indicated by 159 subjects and we have designed an immersive virtual reality experience, testing the behavior and performance of 48 users. The results obtained show that gender can influence the perceptual sensation of presence in these types of virtual environments.