The geo-tracker loses power when it warms up

Dieter W. Fellner

Dieter W. Fellner is Professor of Computer Science at TU Darmstadt, Germany, and Director of the Fraunhofer Institute for Computer Graphics Research IGD, also in Darmstadt.

His research activities in recent years have included efficient rendering and visualization algorithms, generative and reconstructive modeling, virtual and augmented reality, graphical aspects of Internet-based multimedia information systems, cultural heritage and digital libraries as well as visual healthcare technologies.

Currently, he is coordinating a strategic initiative for the development of a digital twin solution for medicine / healthcare.

In addition to his responsibilities in Darmstadt, he is CEO of Fraunhofer Austria Research GmbH and holds a professorship at Graz University of Technology (Austria). Since January 2016, he has been chairman of Fraunhofer Information and Communication Technology Group (IUK-Verbund) and a member of the Fraunhofer Presidential Council. Since 2017, Prof. Fellner has been a member of the board of Fraunhofer Singapore.

Furthermore, he sits on the editorial boards of a number of leading journals for computer graphics, cultural heritage and digital libraries, and is a member of the program committees of many international conferences and workshops.

He is a member of Academia Europaea and a fellow of the Eurographics Association, and received the Eurographics Gold Medal in 2018.

In 2019, Prof. Fellner was awarded an honorary doctorate by the University of Rostock.

Show publication details

2021

IEEE Computer Graphics and Applications

In the field of physically based simulation, high quality of the simulation model is crucial for the correctness of the simulation results and the performance of the simulation algorithm. When working with spline or subdivision models in the context of isogeometric analysis, the quality of the parametrization has to be considered in addition to the geometric quality of the control mesh. Following Cohen et al.'s concept of model quality in addition to mesh quality, we present a parametrization quality metric tailored for Catmull-Clark (CC) solids. It measures the quality of the limit volume based on a quality measure for conformal mappings, revealing local distortions and singularities. We present topological operations that resolve these singularities by splitting certain types of boundary cells that typically occur in interactively designed CC-solid models. The improved models provide higher parametrization quality that positively affects the simulation results without additional computational costs for the solver.

View article

Show publication details

2020

Computer Graphics Forum

Large sparse matrices with compound entries, i.e. complex and quaternionic matrices as well as matrices with dense blocks, are a core component of many algorithms in geometry processing, physically based animation and other areas of computer graphics. We generalize several matrix layouts and apply joint schedule and layout autotuning to improve the performance of the sparse matrix-vector product on massively parallel graphics processing units. Compared to schedule tuning without layout tuning, we achieve speedups of up to 5.5 ×. In comparison to cuSPARSE, we achieve speedups of up to 4.7 ×.

View article | PDF

Show publication details

2020

Archiving 2020 online. Final Program and Proceedings

Archiving

Archiving Conference

The European Cultural Heritage Strategy for the 21st century has led to an increased demand for fast, efficient and faithful 3D digitization technologies for cultural heritage artefacts. Yet, unlike the digital acquisition of cultural goods in 2D which is widely used and automated today, 3D digitization often still requires significant manual intervention, time and money. To overcome this, the authors have developed CultLab3D, the world's first fully automatic 3D mass digitization technology for collections of three-dimensional objects. 3D scanning robots such as the CultArm3D-P are specifically designed to automate the entire 3D digitization process thus allowing to capture and archive objects on a large-scale and produce highly accurate photo-realistic representations.

View article

Show publication details

2020

The Visual Computer

3D objects are used for numerous applications. In many cases not only single objects but also variations of objects are needed. Procedural models can be represented in many different forms, but generally excel in content generation. Therefore this representation is well suited for variation generation of 3D objects. However, the creation of a procedural model can be time-consuming on its own. We propose an automatic generation of a procedural model from a single exemplary 3D object. The procedural model consists of a sequence of parameterizable procedures and represents the object construction process. Changing the parameters of the procedures changes the surface of the 3D object. By linking the surface of the procedural model to the original object surface, we can transfer the changes and enable the possibility of generating variations of the original 3D object. The user can adapt the derived procedural model to easily and intuitively generate variations of the original object. We allow the user to define variation parameters within the procedures to guide a process of generating random variations. We evaluate our approach by computing procedural models for various object types, and we generate variations of all objects using the automatically generated procedural model.

View article

Show publication details

Krispel, Ulrich; Fellner, Dieter W .; Ullrich, Torsten

Distance Measurements of CAD Models in Boundary Representation

2020

Transactions on Computational Science XXXVI

Lecture Notes in Computer Science (LNCS), 12060
Transactions on Computational Science, 12060

The need to analyze and visualize distances between objects arises in many use cases. Although the problem to calculate the distance between two polygonal objects may sound simple, real-world scenarios with large models will always be challenging, but optimization techniques - such as space partitioning - can reduce the complexity of the average case significantly. Our contribution to this problem is a publicly available benchmark to compare distance calculation algorithms. To illustrate the usage, we investigated and evaluated a grid-based distance measurement algorithm.

View article

Show publication details

2020

TU Darmstadt, dissertation, 2020

In modern society, biometrics is gaining more and more importance, driven by the increase in recognition performance of the systems. In some areas, such as automatic border controls, there is no alternative to the application of biometric systems. Despite all the advantages of biometric systems, the vulnerability of these still poses a problem. Facial recognition systems for example offer various attack points, like faces printed on paper or silicone masks. Besides the long known and well researched presentation attacks there is also the danger of the so-called morphing attack. The research field of morphing attacks is quite young, which is why it has only been investigated to a limited extent so far. Publications proposing algorithms for the detection of morphing attacks often lack uniform databases and evaluation methods, which leads to a restricted comparability of the previously published work. Thus, the focus of this thesis is the comprehensive analysis of different features and classifiers in their suitability as algorithms for the detection of morphing attacks. In this context, evaluations are performed with uniform metrics on a realistic morphing database, allowing the simulation of various realistic scenarios. If only the suspected morph is available, a HOG feature extraction in combination with an SVM is able to detect morphs with a D-EER ranging from 13.25% to 24.05%. If a trusted live capture image is available in addition, for example from a border gate, the deep ArcFace features in combination with an SVM can detect morphs with a D-EER ranging from 2.71% to 7.17%.

View article

Show publication details

Andújar, Carlos [Conference Co-Chair] [et al.]; Fellner, Dieter W. [Proceedings Production Ed.]

GCH 2020

2020

Eurographics Association

Eurographics Workshop on Graphics and Cultural Heritage (GCH)

This year the scientific program consists of a keynote lesson, two full papers sessions, two short paper sessions and one poster session. In the keynote session, Dr. Ivan Sipiran will illustrate the connection between computer graphics and artificial intelligence techniques in the field of cultural heritage. Technical sessions deal with traditional topics in our area, as 3D Geometry and Modeling, VR / AR Applications, Image Processing, 3D Data Management and Visualization or Applications for Museums. Finally, we have also invited a set of experts to deal with two specific topics of interest in the current situation: how the pandemic has affected research in our discipline, and how can our discipline help in recovering cultural tourism after the crisis passes.

Show publication details

2020

Print Alliance HAV Produktions GmbH

Show publication details

2020

The Visual Computer

We present a novel bounding volume hierarchy for GPU-accelerated direct volume rendering (DVR) as well as volumetric mesh slicing and inside-outside intersection testing. Our novel octree-based data structure is laid out linearly in memory using space filling Morton curves. As our new data structure results in tightly fitting bounding volumes, boundary markers can be associated with nodes in the hierarchy. These markers can be used to speed up all three use cases that we examine. In addition, our data structure is memory-efficient, reducing memory consumption by up to 75%. Tree depth and memory consumption can be controlled using a parameterized heuristic during construction. This allows for significantly shorter construction times compared to the state of the art. For GPU-accelerated DVR, we achieve performance gain of 8.4 × –13 ×. For 3D printing, we present an efficient conservative slicing method that results in a 3 × -25 × speedup when using our data structure. Furthermore, we improve volumetric mesh intersection testing speed by 5 × -52 ×.

View article | PDF

Show publication details

2020

Darmstadt, TU Darmstadt, diss., 2020

Since several decades, minimally invasive surgery has continuously improved both clinical workflow and outcome. Such procedures minimize patient trauma, decrease hospital stay or reduce risk of infection. Next generation robot-assisted interventions promise to further improve on these advantages while at the same time opening the way to new surgical applications. Temporal Bone Surgery and Endovascular Aortic Repair are two examples for such currently researched approaches, where manual insertion of instruments, subject to a clinician's experience and daily performance, could be replaced by a robotic procedure. In the first, a flexible robot would drill a nonlinear canal through the mastoid, allowing a surgeon access to the temporal bone's apex, a target often unreachable without damaging critical risk structures. For the second example, robotically driven guidewires could significantly reduce the radiation exposure from fluoroscopy, that is exposed to patients and surgeons during navigation through the aorta. These robot-assisted surgeries require preoperative planning consisting of segmentation of risk structures and computation of nonlinear trajectories for the instruments. While surgeons could so far rely on preoperative images and a mental 3D model of the anatomy, these new procedures will make computational assistance inevitable due to the added complexity from image processing and motion planning. The automation of tiresome and manually laborious tasks is therefore crucial for successful clinical implementation. This thesis addresses these issues and presents a preoperative pipeline based on CT images that automates segmentation and trajectory planning. Major contributions include an automatic shape regularized segmentation approach for coherent anatomy extraction as well as an exhaustive trajectory planning step on locally optimized Bézier Splines. It also introduces thorough in silico experiments that perform functional evaluation on real and synthetically enlarged datasets. The benefits of the approach are shown on an in house dataset of otobasis CT scans as well as on two publicly available datasets containing aorta and heart.

View article

Show publication details

2020

GCH 2020

Eurographics Workshop on Graphics and Cultural Heritage (GCH)

Cultural heritage preservation using photometric approaches received increasing significance in the past years. Capturing of these datasets is usually done with high-end cameras at maximum image resolution enabling high quality reconstruction results while leading to immense storage consumptions. In order to maintain archives of these datasets, compression is mandatory for storing them at reasonable cost. In this paper, we make use of the mostly static background of the capturing environment that does not directly contribute information to 3d reconstruction algorithms and therefore may be approximated using lossy techniques. We use a superpixel and figure-ground segmentation based near-lossless image compression algorithm that transparently decides if regions are relevant for later photometric reconstructions. This makes sure that the actual artifact or structured background parts are compressed with lossless techniques. Our algorithm achieves compression rates compared to the PNG image compression standard ranging from 1: 2 to 1: 4 depending on the artifact size.

View article

Show publication details

2020

TU Darmstadt., Diss., 2020

Human activity recognition (HAR) is the automated recognition of individual or group activities from sensor inputs. It deals with a wide range of application areas, such as for health care, assisting technologies, quantified self and safety applications. HAR is the key to build human-centered applications and enables users to seamlessly and naturally interact with each other or with a smart environment. A smart environment is an instrumented room or space equipped with sensors and actuators to perceive the physical state or human activities within this space. The diversity of sensors makes it difficult to use the appropriate sensor to build specific applications. This work aims at presenting sensor-driven applications for human activity recognition in smart environments by using novel sensing categories beyond the existing sensor technologies commonly applied to these tasks. The intention is to improve the interaction for various sub-fields of human activities. Each application addresses the difficulties following the typical process pipeline for designing a smart environment application. At first, I survey most prominent research works with focus on sensor-driven categorization in the research domain of HAR to identify possible research gaps to position my work. I identify two use cases: quantified self and smart home applications. Quantified-self aims at self-tracking and self-knowledge through numbers. Common sensor technology for daily tracking of various aerobic endurance training activities, such as walking, running, or cycling are based on acceleration data with wearable. However, more stationary exercises, such as strength-based training or stretching are also important for a healthy life-style, as they improve body coordination and balance. These exercises are not well tracked by wearing only a single wearable sensor, as these activities rely on coordinated movement of the entire body. I leverage two sensing categories to design two portable mobile applications for remote sensing of these more stationary exercises of physical workout. Sensor-driven applications for smart home domains aim at building systems to make the life of the occupants safer and more convenient. In this thesis, I target at stationary applications to be integrated into the environment to allow a more natural interaction between the occupant and the smart environment. I propose two possible solutions to achieve this task. The first system is a surface acoustic based system which provides a sparse sensor setup to detect a basic set of activities of daily living including the investigation of minimalist sensor arrangement. The second application is a tag-free indoor positioning system. Indoor localization aims at providing location information to build intelligent services for smart homes. Accurate indoor position offers the basic context for high-level reasoning system to achieve more complex contexts. The floor-based localization system using electrostatic sensors is scalable to different room geometries due to its layout and modular composition. Finally, privacy with non-visual input is the main aspect for applications proposed in this thesis. In addition, this thesis addresses the issue of adaptivity from prototypes towards real-world applications. I identify the issues of data sparsity in the training data and data diversity in the real-world data. In order to solve the issue of data sparsity, I demonstrate the data augmentation strategy to be applied on time series to increase the amount of training data by generating synthetic data. Towards mitigating the inherent difference of the development dataset and the real-world scenarios, I further investigate several approaches including metric-based learning and fine-tuning. I explore these methods to fine tune the trained model on limited amount of individual data with and without retrain the pre-trained inference model. Finally some examples are stated as how to deploy the offline model to online processing device with limited hardware resources. Personalization is the task that aims at improving quality of products and services by adapting itself to the current user. In the context of automotive applications, personalization is not only about how drivers sets up the position of their seat or their favorite radio channels. Going beyond that, personalization is also about the preference of driving styles and the individual behaviors in every maneuver executions. One key challenge in personalization is to be able to capture and understand the users from the historical data produced by the users. The data are usually presented in the form of time series and in some cases, those time series can be remarkably long. Capturing and learning from such data poses a challenge for machine learning models. To deal with this problem, this thesis presents an approach that makes uses of recurrent neural networks to capture the time series of behavioral data of drivers and predict theirs lane change intentions.In comparison to previous works, our approach is capable of predicting not only driver’s intention as predefined discrete classes (i.e. left, right and lane keeping) but also as continuous values ​​of the time left until the drivers cross the lane markings. This provides additional information for advanced driver assistance systems to decide when to warn drivers and when to intervene. There are two further aspects that need to be considered when developing a personalized assistance system: inter- and intra-personalization. The former refers to the differences between different users whereas the later indicates the changes in preferences in one user over time (i.e. the differ-ences in driving styles when driving to work versus when being on a city sightseeing tour). In the scope of this thesis, both problems of inter- and intra-personalization are addressed and tackled. Our approach exploits the correlation in driving style between consecutively executed maneuvers to quickly derive the driver’s current preferences. The introduced networks architecture outperforms non-personalized approaches in predicting the preference of driver when turning left. To tackle inter-personalization prob-lems, this thesis makes use of the Siamese architecture with long short-term memory networks for identifying drivers based on vehicle dynamic information. The evaluation, which is carried out on real-world data set collected from 32 test drivers, shows that the network is able to identify unseen drivers. Further analysis on the trained network indicates that it identifies drivers by comparing their behaviors, especially the approaching and turning behaviors.

View article | PDF

Show publication details

Berretti, Stefano [Ed.] [Et al.]; Fellner, Dieter W. [Proceedings Production Ed.]

Smart Tools and Applications in Computer Graphics - Eurographics Italian Chapter Conference

2020

Eurographics Association

Eurographics Italian Chapter Conference - Smart Tools and Applications in computer Graphics (STAG)

View article

Show publication details

Exchange, Reimar; Domajnko, Matevz; Ritz, Martin; Knuth, Martin; Santos, Pedro; Fellner, Dieter W.

Towards 3D Digitization in the GLAM (Galleries, Libraries, Archives, and Museums) Sector - Lessons Learned and Future Outlook

2020

The IPSI BgD Transactions on Internet Research

The European Cultural Heritage Strategy for the 21st century, within the Digital Agenda, one of the flagship initiatives of the Europe 2020 Strategy, has led to an increased demand for fast, efficient and faithful 3D digitization technologies for cultural heritage artefacts. 3D digitization has proven to be a promising approach to enable precise reconstructions of objects. Yet, unlike the digital acquisition of cultural goods in 2D which is widely used and automated today, 3D digitization often still requires significant manual intervention, time and money. To enable heritage institutions to make use of large scale, economic, and automated 3D digitization technologies, the Competence Center for Cultural Heritage Digitization at the Fraunhofer Institute for Computer Graphics Research IGD has developed CultLab3D, the world's first fully automatic 3D mass digitization technology for collections of three-dimensional objects. 3D scanning robots such as the CultArm3D-P are specifically designed to automate the entire 3D digitization process thus allowing to capture and archive objects on a large-scale and produce highly accurate photo-realistic representations. The unique setup allows to shorten the time needed for digitization from several hours to several minutes per artefact.

PDF

Show publication details

2020

The visual computing applications of Fraunhofer IGD rely on realistic visualization and combine this with important specialist knowledge in order to convey complex issues as early as the planning phase. We offer both professionals and citizens an interactive 3D web application that puts the project development in a comprehensible, realistic context - this leads to significantly more acceptance of the results. The city of Hamburg is already implementing such a scenario. Citizens can suggest new planting locations for trees and receive direct feedback on whether all guidelines are being adhered to - at the same time, the urban planning software provides information about possible alternative locations. Transparency and quick feedback allow citizens to participate actively and productively in urban planning processes. The principle is transferable. Whether it is about infrastructure for broadband expansion, traffic or renewable energies: All participants meet regardless of time and location, all have the same comprehensive information - the discussion takes place on a virtual level. Fraunhofer IGD has also created new opportunities in the field of education: economical, ecological, efficient. Anyone who learns through several sensory channels, such as language and images, can store knowledge better. Since 2019, volunteers at the German Red Cross have been practicing in virtual training worlds how an ambulance is designed - sometimes there is no ambulance available to practice. Or: What happens when trainees at Heidelberger Druckmaschinen AG are supposed to understand, maintain and repair complex equipment? Stop production and take the machine apart and put it back together again? Thanks to virtual learning rooms, the trainees can »see«, recognize and understand the processes inside the machine. Visual Computing with Virtual Reality (VR) and Augmented Reality (AR) is and will remain exciting, not just for science: According to a study by PricewaterhouseCoopers, VR and AR have great potential. In 2030, 400,000 people will have to deal with it in the workplace in Germany alone, currently 15,000.

Show publication details

2020

TU Darmstadt, dissertation, 2020

Continuous surface representations, such as B-spline and Non-Uniform Rational B-spline (NURBS) surfaces are the de facto standard for modeling 3D objects - thin shells and solid objects alike - in the field of Computer-Aided Design (CAD). For performing physically based simulation, Finite Element Analysis (FEA) has been the industry standard for many years. In order to analyze physical properties such as stability, aerodynamics, or heat dissipation, the continuous models are discretized into finite element (FE) meshes. A tight integration of and a smooth transition between geometric design and physically based simulation are key factors for an eÿcient design and engineering workflow. Con-verting a CAD model from its continuous boundary representation (B-Rep) into a discrete volumetric representation for simulation is a time-consuming process that introduces approximation errors and often requires manual interaction by the engineer. Deriving design changes directly from the simulation results is especially diÿcult as the meshing process is irreversible. Isogeometric Analysis (IGA) tries to overcome this meshing hurdle by using the same representation for describing the geometry and for performing the simulation. Most commonly, IGA is performed on bivariate and trivariate spline representations (B-spline or NURBS surfaces and volumes) [HCB05]. While existing CAD B-Rep models can be used directly for simulating thin-shell objects, simulating solid objects requires a conversion from spline surfaces to spline volumes. As spline volumes need a trivariate tensor-product topology, complex 3D objects must be represented via trimming or by connecting multiple spline volumes, limiting the continuity to C0 [ME16; DSB19]. As an alternative to NURBS or B-splines, subdivision models allow for representing complex topologies with as a single entity, removing the need for trimming or tiling and potentially providing higher continuity. While subdivision surfaces have shown promising results for designing and simulating shells [WHP11; Pan + 15; RAF16], IGA on subdivision volumes remained mostly unexplored apart from the work of Burkhart et al. [BHU10b; Bur11]. In this dissertation, I investigate how volumetric subdivision representations are beneficial for a tighter integration of geometric modeling and physically based simulation. Focusing on Catmull-Clark (CC) solids, I present novel techniques in the areas of eÿcient limit evaluation, volumetric modeling, numerical integration, and mesh quality analysis. I present an eÿcient link to FEA, as well as my IGA approach on CC solids that improves upon Burkhart et al.’s proof of concept [BHU10b] with constant-time limit evaluation, more accurate integration, and higher mesh quality. Eÿcient limit evaluation is a key requirement when working with subdivision models in geometric design, visualization, simulation, and 3D printing. In this dissertation, I present the first method for constant-time volumetric limit evaluation of CC solids. It is faster than the subdivision-based approach by Burkhart et al. [BHU10b] for every topological constellation and parameter point that would require more than two local subdivision steps. Adapting the concepts of well-known surface modeling tools, I present a volumetric modeling environment for CC-solid control meshes. Consistent volumetric modeling operations built from a set of novel volumetric Euler operators allow for creating and modifying topologically consistent volumetric meshes. Furthermore, I show how to manipulate groups of control points via parameters, how to avoid intersections with inner control points while modeling the outer surface, and how to use CC solids in the context of multi-material additive manufacturing. For coupling of volumetric subdivision models with established FE frameworks, I present an eÿcient and consistent tetrahedral mesh generation technique for CC solids. The technique exploits the inherent volumetric structure of CC-solid models and is at least 26 × faster than the tetrahedral meshing algorithm provided by CGAL [Jam + 15]. This allows to re-create or update the tetrahedral mesh almost instantly when changing the CC-solid model. However, the mesh quality strongly depends on the quality of the control mesh. In the context of structural analysis, I present my IGA approach on CC solids. The IGA approach yields converging stimulation results for models with fewer elements and fewer degrees of freedom than FE simulations on tetrahedral meshes with linear and higher-order basis functions. The solver also requires fewer iterations to solve the linear system due to the higher continuity throughout the simulation model provided by the subdivision basis functions. Extending Burkhart et al's method [BHU10b], my hierarchical quadrature scheme for irregular CC-solid cells increases the accuracy of the integrals for computing surface areas and element sti stnesses. Furthermore, I introduce a quality metric that quantifies the parametrization quality of the limit volume, revealing distortions, inversions, and singularities. The metric shows that cells with multiple adjacent boundary faces induce singularities in the limit, even for geometrically well-shaped control meshes. Finally, I present a set of topological operations for splitting such boundary cells - resolving the singularities. These improvements further reduce the amount of elements required to obtain converging results as well as the time required for solving the linear system.

View article

Show publication details

2019

Computers & Graphics

In the competition for the volumetric representation most suitable for functionally graded materials in additively manufactured (AM) objects, volumetric subdivision schemes, such as Catmull-Clark (CC) solids, are widely neglected. Although they show appealing properties, e_cient implementations of some fundamental algorithms are still missing. In this paper, we present a fast algorithm for direct slicing of CC-solids generating bitmaps printable by multi-material AMmachines. Our method optimizes runtime by exploiting constant time limit evaluation and other structural characteristics of CCsolids. We compare our algorithm with the state of the art in trivariate trimmed spline representations and show that our algorithm has similar runtime behavior as slicing trivariate splines, fully supporting the benefits of CC-solids.

View article

Show publication details

2019

GCH 2019

Eurographics Workshop on Graphics and Cultural Heritage (GCH)

Planning exhibitions of cultural artifacts is always challenging. Artifacts can be very sensitive to the environment and therefore their display can be risky. One way to circumvent this is to build replicas of these artifacts. Here, 3D digitization and reproduction, either physical via 3D printing or virtual, using computer graphics, can be the method of choice. For this use case we present a workflow, from photogrammetric acquisition in challenging environments to representation of the acquired 3D models in different ways, such as online visualization and color 3D printed replicas. This work can also be seen as a first step towards establishing a workflow for full color end-to-end reproduction of artifacts. Our workflow was applied on cultural artifacts found around the “Roseninsel” (Rose Island), an island in Lake Starnberg (Bavaria), in collaboration with the Bavarian State Archaeological Collection in Munich. We demonstrate the results of the end-to-end reproduction workflow leading to virtual replicas (online 3D visualization, virtual and augmented reality) and physical replicas (3D printed objects). In addition, we discuss potential optimizations and briefly present an improved state-of-the-art 3D digitization system for fully autonomous acquisition of geometry and colors of cultural heritage objects.

View article

Show publication details

Dahlke, Jannik Oliver; Fellner, Dieter W. [1. Review]; Erdt, Marius [2. Review]

Enhancing the Texture Quality of 3D Building Models

2019

Darmstadt, TU, Master Thesis, 2019

3D-City Models have many applications, e.g urban emergency simulations, city planning, 3D city visualization for movies, games and more. Textures play an important role in realizing photorealistic and immersive renderings. Often these textures are of low quality due to the complexity of mass scale texture acquisition. One severe artefact is the occlusion of building facades through neighboring roofs and trees. This thesis will explore a method that combines recent development in deep learning inpainting methods with domain specific knowledge about building facades. This method is able to remove an occlusion from a building facade by filling it with visually coherent regular facade elements. A state-of-the-art deep learning inpainting method has been extended by using segmentation information as additional input and additional loss metrics among other extensions. These proposed adaptions are able to improve upon current state-of-the-art methods by reducing blurriness, checkerboard artefacts, color smear and by increasing structural integrity of the building facades especially for inpainting large images.

Show publication details

Landesberger, Tatiana von [Program Chair]; Turkay, Cagatay [advisor]; Kohlhammer, Jörn [Steering Committee]; Keim, Daniel A. [Advisor]; Fellner, Dieter W. [Proceedings Production Ed.]

EuroVA 2019

2019

Eurographics Association

International EuroVis Workshop on Visual Analytics (EuroVA)

Show publication details

Rizvic, Selma [Program Co-Chair]; Rodriguez Echavarria, Karina [Program Co-Chair]; Fellner, Dieter W. [Proceedings Production Ed.]; Ramic-Brkic, Belma [Local Chair]

GCH 2019

2019

Eurographics Association

Eurographics Workshop on Graphics and Cultural Heritage (GCH)

The Graphics and Cultural Heritage research community has vast experience in interdisciplinary research and in seeking technical innovation which has a societal application. As such, in this 17th edition of the Workshop on Graphics and Cultural Heritage (GCH 2019) we placed special attention on the role of this research community for proposing novel research which underpins the safeguarding of Cultural Heritage in the digital age while addressing the social, environmental and economic challenges. Taking place at the heart of the Balkans, in the city of Sarajevo, this year's event explores the role of computer graphics and other digital technologies in the preservation and provision of access to cultural heritage which might be vulnerable from natural and man-made threats such as climate change, economic hardship, violence and neglect. The program includes a variety of research contributions that address these pressing needs. Novel methods for the digitization of artefacts are presented, including open and end-to-end processes for 3D documentation and reproductions, capturing complex materials, introducing multispectral imaging processes and finding compression methods for images resulting from digitization processes. The analysis and classification of cultural heritage material is also presented, including methods for the analysis of historical films, analysis of cracks on painted surfaces, classification of clay statuettes, retrieval of painted pottery and the exploration methods for annotated datasets. Engagement with virtual environments is presented through research conducted on virtual museums, and Augmented Reality (AR) to engage the public and Virtual Reality (VR) environments to enable them to experience seismic simulations. 3D design research includes the design of ancient garments and the extraction of 3D scenes from bas-reliefs. Community engagement with cultural heritage is proposed through storytelling mechanisms using technologies such as AR, VR and 3D printed replicas.

View article

Show publication details

2019

Darmstadt, TU., Diss., 2019

Virtual prototyping, the iterative process of using computer-aided (CAx) modeling, simulation, and visualization tools to optimize prototypes and products before manufacturing the first physical artifact, plays an increasingly important role in the modern product development process. Especially due to the availability of affordable additive manufacturing (AM) methods (3D printing), it is becoming increasingly possible to manufacture customized products or even for customers to print items for themselves. In such cases, the first physical prototype is frequently the final product. In this dissertation, methods to efficiently parallelize modeling, simulation, and visualization operations are examined with the goal of reducing iteration times in the virtual prototyping cycle, while simultaneously improving the availability of the necessary CAx tools. The presented methods focus on parallelization on programmable graphics processing units (GPUs). Modern GPUs are fully programmable massively parallel many core processors that are characterized by their high energy efficiency and good price performance ratio.Additionally, GPUs are already present in many workstations and home computers due to their use in computer-aided design (CAD) and computer games. However, specialized algorithms and data structures are required to make efficient use of the processing power of GPUs. Using the novel GPU-optimized data structures and algorithms as well as the new applications of compiler technology introduced in this dissertation, speedups between approximately one (10 ×) and more than two orders of magnitude (> 100 ×) are achieved compared to the state of the art in the three core areas of virtual prototyping. Additionally, memory use and required bandwidths are reduced by up to nearly 86%. As a result, not only can computations on existing models be executed more efficiently but larger models can be created and processed as well. In the area of ​​modeling, efficient discrete mesh processing algorithms are examined with a focus on volumetric meshes. In the field of simulation, the assembly of the large sparse system matrices resulting from the finite element method (FEM) and the simulation of fluid dynamics are accelerated. As sparse matrices form the foundation of the presented approaches to mesh processing and simulation, GPU-optimized sparse matrix data structures and hardware- and domain-specific automatic tuning of these data structures are developed and examined as well. In the area of ​​visualization, visualization latencies in remote visualization of cloud-based simulations are reduced by using an optimizing query compiler. By using hybrid visualization, various user interactions can be performed without network round trip latencies.

View article

Show publication details

2019

Fraunhofer IGD recently bundled its research activities into four main topics, which form the basis of its work and link various topics across departments. One of these main themes is "Visual Computing as a Service - The Platform for Applied Visual Computing". The basis of this universal platform for visual computing solutions has been laid and is continuously being expanded. This technological approach forms the basis for the other key topics. In "Individual Health - Digital Solutions for Healthcare", the data that arise in personalized medicine are examined - with the help of the institute's visual computing technologies. In the main theme "Intelligent City - Innovative, Digital and Sustainable" the question is how one can support the life cycle of urban processes. And the main theme "Digitized Work - People in Industry 4.0" is primarily about supporting people in the production that has been changed by digitization.

Show publication details

2019

Vision, Modeling, and Visualization

Vision, Modeling, and Visualization (VMV)

Large sparse matrices with compound entries, i.e., complex and quaternionic matrices as well as matrices with dense blocks, are a core component of many algorithms in geometry processing, physically based animation, and other areas of computer graphics. We generalize several matrix layouts and apply joint schedule and layout autotuning to improve the performance of the sparse matrix-vector product on massively parallel graphics processing units. Compared to schedule tuning without layout tuning, we achieve speedups of up to 5: 5x. In comparison to cuSPARSE, we achieve speedups of up to 4: 7x.

View article

Show publication details

2019

GCH 2019

Eurographics Workshop on Graphics and Cultural Heritage (GCH)

Photometric multi-view 3D geometry reconstruction and material capture are important techniques for cultural heritage digitalization. Capturing images of artifacts with high resolution and high dynamic range and the possibility to store them losslessly enables future proof application of this data. As the images tend to consume immense amounts of storage, compression is essential for long time archiving. In this paper, we present a lossless image compression approach for multi-view and material reconstruction datasets with a strong focus on data created from cultural heritage digitalization. Our approach achieves compression rates of 2: 1 compared against an uncompressed representation and 1.24: 1 when compared against Gzip.

View article

Show publication details

Cui, Jian; Sourin, Alexei [supervisor]; Fellner, Dieter W. [co-supervisor]; Kuijper, Arjan [co-supervisor]

Mid-air hand interaction with optical tracking for 3D modeling

2019

Singapore, Nanyang Technological Univ., Diss., 2019

Compared to common 2D interaction done with mouse and other 2D tracking devices, 3D hand tracking with low-cost optical cameras can provide more degrees of freedom, as well as natural gestures when shape modeling and assembling are done in virtual spaces. However, though quite precise, the optical tracking devices cannot avoid problems intrinsic to hand interaction, such as hand tremor and jump release, and they also introduce an additional problem of occlusion. This thesis investigates whether interaction during 3D modeling can be improved by using optical sensors so that 3D tasks can be performed in a way similar to interaction in real life and as efficient as when using common 2D-tracking based interaction while still minimizing the intrinsic problems of precise hand manipulations and optical problems. After surveying the relevant works and analyzing technical capabilities of the commonly available optical sensors, two approaches are thoroughly investigated for the natural mid-air hand interaction in precise 3D modeling - they are collision-based and gesture-based interaction. For collision-based methods, a set of virtual interaction techniques is proposed to realistically simulate real-life manipulation and deformation with one and two hands. For gesture-based interaction, a core set of interaction techniques is also devised which allows natural real-life interaction ways to be used. In addition, algorithms are proposed for both collision-based and gesture-based interaction to enhance the precision while minimizing the problems of hand tremor and jump release. However, the results show that virtual interaction designed with collision-based methods is always slower than real-life interaction due to missing force feedback. Although common gesture-based interaction is less affected by its problem, it still cannot completely get rid of the problems of occlusion and jump release. Eventually, a new method of gesture-based interaction is proposed to use hands in a way similar to how it is done when playing the Theremin - an electronic musical instrument controlled without physical contact by hands of the performer. It is suggested that the dominant hand controls manipulation and deformation of objects while the non-dominant hand controls grasping, releasing and variable precision of interaction. Based on this method, a generic set of reliable and precise gesture-based interaction techniques is designed and implemented for various manipulation and deformation tasks. It is then proved with the user studies that for the tasks involving 3D manipulations and deformations, the proposed way of hand interaction is easy to learn, not affected by the common problems of hand tracking, as well as more convenient and faster than common 2D interaction done with mouse for some 3D tasks.

View article