Die »Selected Readings in Computer Graphics 2014« bestehen aus 40 ausgewählten Artikeln von insgesamt 204 wissenschaftlichen Veröffentlichungen. 

Die Beiträge kommen aus dem Fraunhofer-Institut für Graphische Datenverarbeitung IGD mit Standorten in Darmstadt wie auch in Rostock, Singapur und Graz, den Partner-Instituten an den jeweiligen Universitäten, der Fachgruppe Graphisch-Interaktive Systeme der Technischen Universität Darmstadt, der Computergraphics and Communication Gruppe am Institut für Informatik der Universität Rostock, der Nanyang Technological University (NTU), Singapur, und dem Visual Computing Excellenz-Cluster der Technischen Universität Graz. Sie alle arbeiten eng in Projekten sowie Forschung und Entwicklung im Gebiet der Computer Graphik zusammen.

Alle Artikel erschienen vorher in verschiedenen wissenschaftlichen Büchern, Zeitschriften, Konferenzbänden und Workshops. Die Veröffentlichungen mussten einen gründlichen Begutachtungsprozess durch international führende Experten und etabilierte technische Vereinigungen durchlaufen. Deshalb geben die Selected Readings einen recht guten und detaillierten Überblick über die wissenschaftlichen Entwicklungen in der Computer Graphik im Jahr 2014. Sie werden von Professor Dieter W. Fellner, dem Leiter des Fraunhofer-Instituts für Graphische Datenverarbeitung IGD in Darmstadt zusammengestellt. Er ist zugleich Professor am Fachbereich Informatik der Technischen Universität Darmstadt und Professor an der Fakultät für Informatik der Technischen Universität Graz.

Die Selected Readings in Computer Graphics 2014 befassen sich mit Aspekten und Trends der Forschung und Entwicklung in Computer Graphik auf den Gebieten

  • Digitale Gesellschaft
  • Virtuelles Engineering
  • Visuelle Entscheidungshilfe
  • Visual Computing Forschung

Liste der Publikationen

Bader, Sebastian; Aehnelt, Mario

Tracking Assembly Processes and Providing Assistance in Smart Factories

2014

Duval, Béatrice (Ed.) et al.: ICAART 2014, Vol. 1 : Proceedings of the 6th International Conference on Agents and Artificial Intelligence. SciTePress, 2014, pp. 161-168

International Conference on Agents and Artificial Intelligence (ICAART) <6, 2014, Angers, France>

Tracking assembly processes is a necessary prerequisite to provide assistance in smart factories. In this paper, we show how to track the construction of complex components. For this we employ formal task models as background knowledge and simple sensors like RFIDs. The background knowledge is converted into a probabilistic model that actually tracks the process. As a result, we are able to provide assistance in smart factories. We discuss the performance of the approach, as well as potential applications.

Behrisch, Michael; Davey, James; Fischer, Fabian; Thonnard, Olivier; Schreck, Tobias; Keim, Daniel A.; Kohlhammer, Jörn

Visual Analysis of Sets of Heterogeneous Matrices Using Projection-Based Distance Functions and Semantic Zoom

2014

Computer Graphics Forum, Vol.33 (2014), 3, pp. 411-420

Eurographics Conference on Visualization (EuroVis) <16, 2014, Swansea, Wales, UK>

Matrix visualization is an established technique in the analysis of relational data. It is applicable to large, dense networks, where node-link representations may not be effective. Recently, domains have emerged in which the comparative analysis of sets of matrices of potentially varying size is relevant. For example, to monitor computer network traffic a dynamic set of hosts and their peer-to-peer connections on different ports must be analysed. A matrix visualization focused on the display of one matrix at a time cannot cope with this task.

We address the research problem of the visual analysis of sets of matrices. We present a technique for comparing matrices of potentially varying size. Our approach considers the rows and/or columns of a matrix as the basic elements of the analysis. We project these vectors for pairs of matrices into a low-dimensional space which is used as the reference to compare matrices and identify relationships among them. Bipartite graph matching is applied on the projected elements to compute a measure of distance. A key advantage of this measure is that it can be interpreted and manipulated as a visual distance function, and serves as a comprehensible basis for ranking, clustering and comparison in sets of matrices. We present an interactive system in which users may explore the matrix distances and understand potential differences in a set of matrices. A flexible semantic zoom mechanism enables users to navigate through sets of matrices and identify patterns at different levels of detail. We
demonstrate the effectiveness of our approach through a case study and provide a technical evaluation to illustrate its strengths.

Bernard, Jürgen; Sessler, David; Ruppert, Tobias; Davey, James; Kuijper, Arjan; Kohlhammer, Jörn

User-Based Visual-Interactive Similarity Definition for Mixed Data Objects - Concept and First Implementation

2014

Skala, Vaclav (Ed.): WSCG 2014. Communication Papers Proceedings : 22nd International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision. Plzen: University of West Bohemia, 2014, pp. 329-338

International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG) <22, 2014, Plzen, Czech Republic>

The definition of similarity between data objects plays a key role in many analytical systems. The process of similarity definition comprises several challenges as three main problems occur: different stakeholders, mixed data, and changing requirements. Firstly, in many applications the developers of the analytical system (data scientists) model the similarity, while the users (domain experts) have distinct (mental) similarity notions. Secondly, the definition of similarity for mixed data types is challenging. Thirdly, many systems use static similarity models that cannot adapt to changing data or user needs. We present a concept for the development of systems that support the visual-interactive similarity definition for mixed data objects emphasizing 15 crucial steps. For each step different design considerations and implementation variants are presented, revealing a large design space. Moreover, we present a first implementation of our concept, enabling domain experts to
express mental similarity notions through a visual-interactive system. The provided implementation tackles the different-stakeholders problem, the mixed data problem, and the changing requirements problem. The implementation is not limited to a specific mixed data set. However, we show the applicability of our implementation in a case study where a functional similarity model is trained for countries as objects.

Bernard, Jürgen; Steiger, Martin; Widmer, Sven; Lücke-Tieke, Hendrik; May, Thorsten; Kohlhammer, Jörn

Visual-interactive Exploration of Interesting Multivariate Relations in Mixed Research Data Sets

2014

Computer Graphics Forum, Vol.33 (2014), 3, pp. 291-300

Eurographics Conference on Visualization (EuroVis) <16, 2014, Swansea, Wales, UK>

The analysis of research data plays a key role in data-driven areas of science. Varieties of mixed research data sets exist and scientists aim to derive or validate hypotheses to find undiscovered knowledge. Many analysis techniques identify relations of an entire dataset only. This may level the characteristic behavior of different subgroups in the data. Like automatic subspace clustering, we aim at identifying interesting subgroups and attribute sets.

We present a visual-interactive system that supports scientists to explore interesting relations between aggregated bins of multivariate attributes in mixed data sets. The abstraction of data to bins enables the application of statistical dependency tests as the measure of interestingness. An overview matrix view shows all attributes, ranked with respect to the interestingness of bins. Complementary, a node-link view reveals multivariate bin relations by positioning dependent bins close to each other. The system supports information drill-down based on both expert knowledge and algorithmic support. Finally, visual-interactive subset clustering assigns multivariate bin relations to groups. A list-based cluster result representation enables the scientist to communicate multivariate findings at a glance. We demonstrate the applicability of the system with two case studies from the earth observation domain and the prostate cancer research domain. In both cases, the system enabled us to
identify the most interesting multivariate bin relations, to validate already published results, and, moreover, to discover unexpected relations.

Braun, Andreas; Wichert, Reiner; Kuijper, Arjan; Fellner, Dieter W.

A Benchmarking Model for Sensors in Smart Environments

2014

Aarts, Emile (Ed.) et al.: Ambient Intelligence : European Conference, AmI 2014. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8850), pp. 242-257

European Conference on Ambient Intelligence (AmI) <11, 2014, Eindhoven, The Netherlands>

In smart environments, developers can choose from a large variety of sensors supporting their use case that have specific advantages or disadvantages. In this work we present a benchmarking model that allows estimating the utility of a sensor technology for a use case by calculating a single score, based on a weighting factor for applications and a set of sensor features. This set takes into account the complexity of smart environment systems that are comprised of multiple subsystems and applied in non-static environments. We show how the model can be used to find a suitable sensor for a use case and the inverse option to find suitable use cases for a given set of sensors. Additionally, extensions are presented that normalize differently rated systems and compensate for central tendency bias. The model is verified by estimating technology popularity using a frequency analysis of associated search terms in two scientific databases.

Butt, Moazzam; Damer, Naser

Helper Data Scheme for 2D Cancelable Face Recognition Using Bloom Filters

2014

Mustra, Mario (Ed.) et al.: lWSSIP 2014. Proceedings : 21st International Conference on Systems, Signals and Image Processing. Zagreb: Faculty of Electrical Engineering and Computing, University of Zagreb, 2014, pp. 271-274

International Conference on Systems, Signals and Image Processing (lWSSIP) <21, 2014, Dubrovnik, Croatia>

Biometrics provide a source of automated recognition of individuals based on their physiological and behavioral characteristics. As per Directive 95/46/EC, biometric data is considered to be personal data. And according to article 8 of the European Convention on Human Rights, personal data needs to be privacy preserved. Biometric template protection mechanisms provide a privacy preserved biometric authentication. Such mechanisms assist irreversibility, revocability and unlinkability of biometric templates. Recently, a bloom filter based approach was proposed to generate irreversible iris template.

In this paper, a helper data scheme for 2D cancelable face verification using bloom filters is proposed. The positions of most representative features (stable features) are used as helper data, which helps in the face recognition. The features used are extracted using Local Binary Linear Discriminant Analysis. The effect of stable features on recognition performance under scenarios of with and without using bloom filters is investigated. In addition, recognition performance after compressing multiple features into a single bloom filter is presented. The results are experimentally proved on two benchmark databases namely LFW and ORL datasets.

Dambruch, Jens; Krämer, Michel

Leveraging Public Participation in Urban Planning with 3D Web Technology

2014

Polys, Nicholas F. (General Chair) et al.: Proceedings Web3D 2014 : 19th International Conference on 3D Web Technology. New York: ACM, 2014, pp. 117-124

International Conference on 3D Web Technology (WEB3D) <19, 2014, Vancouver, BC, Canada>

In this paper we present a web-based platform that makes use of HTML5 technology and WebGL to facilitate public participation in urban planning. It consists of components that enable city administrations to present urban plans to the public and to engage with stakeholders. One of these components uses the open source library X3DOM to visualise 3D content-for example, a city model containing a 3D representation of a planned building. Since X3DOM does not need additional software to be installed on the user's system our implementation is more portable than previous work.

Our solution is based on the open source software Liferay which allows it to be configured for various urban planning projects. In order to enable communication between different web application components residing in inline frames (iframes) we implemented a special message bus based on HTML5 postMessage. In this paper we describe implementation details, but we also intensively discuss the possibilities of modern web technology for urban planning. We motivate the use of such technology through three examples that can be implemented using our web application. In this paper we also present results from evaluating our application in user workshops carried out within the project urbanAPI that is funded by the European Commission. Finally, we draw conclusions and discuss possibilities for future urban planning use cases.

Damer, Naser; Opel, Alexander

Multi-biometric Score-Level Fusion and the Integration of the Neighbors Distance Ratio

2014

Aurélio, Campilho (Ed.) et al.: Image Analysis and Recognition. Proceedings Part II : 11th International Conference, ICIAR 2014. Berlin; Heidelberg; New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8815), pp. 85-93

International Conference on Image Analysis and Recognition (ICIAR) <11, 2014, Vilamoura, Portugal>

Multi-biometrics aims at building more accurate unified biometric decisions based on the information provided by multiple biometric sources. Information fusion is used to optimize the process of creating this unified decision. In previous works dealing with score-level multibiometric fusion, the scores of different biometric sources belonging to the comparison of interest are used to create the fused score. The novelty of this work focuses on integrating the relation of the fused scores to other comparisons within a 1:N comparison. This is performed by considering the neighbors distance ratio in the ranked comparisons set within a classification-based fusion approach. The evaluation was performed on the Biometric Scores Set BSSR1 database and the enhanced performance induced by the integration of neighbors distance ratio was clearly presented.

Dolereit, Tim; Kuijper, Arjan

Converting Underwater Imaging into Imaging in Air

2014

Battiato, Sebastiano (Ed.) et al.: VISAPP 2014 - Volume I : Proceedings of the International Conference on Computer Vision Theory and Applications. SciTePress, 2014, pp. 96-103

International Conference on Computer Vision Theory and Applications (VISAPP) <9, 2014, Lisbon, Portugal>

The application of imaging devices in underwater environments has become a common practice. Protecting the camera's constituent electric parts against water leads to refractive effects emanating from the water-glassair transition of light rays. These non-linear distortions can not be modeled by the pinhole camera model. For our new approach we focus on flat interface systems. By handling refractive effects properly, we are able to convert the problem to imaging conditions in air. We show that based on the location of virtual object points in water, virtual parameters of a camera following the pinhole camera model can be computed per image ray. This enables us to image the same object as if it was situated in air. Our novel approach works for an arbitrary camera orientation to the refractive interface. We show experimentally that our adopted physical methods can be used for the computation of 3D object points by a stereo camera system with much higher precision than with a naive
in-situ calibration.

Edelsbrunner, Johannes; Krispel, Ulrich; Havemann, Sven; Sourin, Alexei; Fellner, Dieter W.

Constructive Roof Geometry

2014

2014 International Conference on Cyberworlds : CW 2014. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2014, pp. 63-70

International Conference on Cyberworlds (CW) <13, 2014, Santander, Spain>

While the growing demand for new building models contained in virtual worlds, games, and movies, makes the easy and fast creation of modifiable models more and more important, 3D modeling of buildings can be a tedious task due to their sometimes complex geometry. For historic buildings, especially the roofs can be challenging. We present a new method of combining simple building solids to form more complex buildings, and give an emphasis on the blending of roof faces. This can be integrated in common pipelines for procedural modeling of buildings and will bring more expressiveness than existing methods.

Franke, Tobias

Delta Voxel Cone Tracing

2014

Julier, Simon (Ed.) et al.: IEEE International Symposium on Mixed and Augmented Reality - Science & Technology 2014 : ISMAR 2014. Piscataway, NJ: IEEE Service Center, 2014, pp. 39-44

IEEE International Symposium on Mixed and Augmented Reality (ISMAR) <13, 2014, Munich, Germany>

Mixed reality applications which must provide visual coherence between synthetic and real objects need relighting solutions for both: synthetic objects have to match lighting conditions of their real counterparts, while real surfaces need to account for the change in illumination introduced by the presence of an additional synthetic object. In this paper we present a novel relighting solution called Delta Voxel Cone Tracing to compute both direct shadows and first bounce mutual indirect illumination. We introduce a voxelized, pre-filtered representation of the combined real and synthetic surfaces together with the extracted illumination difference due to the augmentation. In a final gathering step this representation is conetraced and superimposed onto both types of surfaces, adding additional light from indirect bounces and synthetic shadows from antiradiance present in the volume. The algorithm computes results at interactive rates, is temporally coherent and to our knowledge
provides the first real-time rasterizer solution for mutual diffuse, glossy and perfect specular indirect reflections between synthetic and real surfaces in mixed reality.

Fuhrmann, Simon; Goesele, Michael

Floating Scale Surface Reconstruction

2014

ACM Transactions on Graphics, Vol.33 (2014), 4, 11 p.; Article No. 46

International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) <41, 2014, Vancouver, BC, Canada>

Any sampled point acquired from a real-world geometric object or scene represents a finite surface area and not just a single surface point. Samples therefore have an inherent scale, very valuable information that has been crucial for high quality reconstructions. We introduce a new method for surface reconstruction from oriented, scale-enabled sample points which operates on large, redundant and potentially noisy point sets. The approach draws upon a simple yet efficient mathematical formulation to construct an implicit function as the sum of compactly supported basis functions. The implicit function has spatially continuous "floating" scale and can be readily evaluated without any preprocessing. The final surface is extracted as the zero-level set of the implicit function. One of the key properties of the approach is that it is virtually parameter-free even for complex, mixed-scale datasets. In addition, our method is easy to implement, scalable and does not require any global
operations. We evaluate our method on a wide range of datasets for which it compares favorably to popular classic and current methods.

Gollmer, Sebastian T.; Kirschner, Matthias; Buzug, Thorsten M.; Wesarg, Stefan

Using Image Segmentation for Evaluating 3D Statistical Shape Models Built With Groupwise Correspondence Optimization

2014

Computer Vision and Image Understanding, Vol.125 (2014), pp. 283-303

Statistical shape models (SSMs) are a well-established tool in medical image analysis. The most challenging part of SSM construction, which cannot be solved trivially in 3D, is the establishment of corresponding points, so-called landmarks. A popular approach for solving the correspondence problem is to minimize a groupwise objective function using the optimization by re-parameterization approach. To this end, several objective functions, optimization strategies and re-parameterization functions have been proposed.

While previous evaluation studies focused mainly on the objective function, we provide a detailed evaluation of different correspondence methods, objective functions, re-parameterization, and optimization strategies. Moreover and contrary to previous works, we use distance measures that compare landmark shape vectors to the original input shapes, thus adequately accounting for correspondences which undersample certain regions of the input shapes. Additionally, we segment binary expert segmentations to benchmark SSMs constructed from different correspondences. This new evaluation technique overcomes limitations of the correspondence based evaluation and allows for directly quantifying the influence of the correspondence on the expected segmentation accuracy. From our evaluation results we identify pitfalls of the current approach and derive practical recommendations for implementing a groupwise optimization pipeline.

Große-Puppendahl, Tobias; Herber, Sebastian; Wimmer, Raphael; Englert, Frank; Beck, Sebastian; Wilmsdorff, Julian von; Wichert, Reiner; Kuijper, Arjan

Capacitive Near-Field Communication for Ubiquitous Interaction and Perception

2014

ACM SIGCHI: UbiComp' 14 : Proceedings of the 2014 ACM International Joint Conference on Pervasive and Ubiquitous Computing. New York: ACM Press, 2014, pp. 231-242

International Conference on Ubiquitous Computing (Ubicomp) <16, 2014, Seattle, WA, USA>

Smart objects within instrumented environments offer an always available and intuitive way of interacting with a system. Connecting these objects to other objects in range or even to smartphones and computers, enables substantially innovative interaction and sensing approaches. In this paper, we investigate the concept of Capacitive Near-Field Communication to enable ubiquitous interaction with everyday objects in a short-range spatial context. Our central contribution is a generic framework describing and evaluating this communication method in Ubiquitous Computing. We prove the relevance of our approach by an open-source implementation of a low-cost object tag and a transceiver offering a high-quality communication link at typical distances up to 15 cm. Moreover, we present three case studies considering tangible interaction for the visually impaired, natural interaction with everyday objects, and sleeping behavior analysis.

Happel, Kathrin; Dörsam, Edgar; Urban, Philipp

Measuring Isotropic Subsurface Light Transport

2014

Optics Express, Vol.22 (2014), 8, pp. 9048-9062

Subsurface light transport can affect the visual appearance of materials significantly. Measuring and modeling this phenomenon is crucial for accurately reproducing colors in printing or for rendering translucent objects on displays. In this paper, we propose an apparatus to measure subsurface light transport employing a reference material to cancel out adverse signals that may bias the results. In contrast to other approaches, the setup enables improved focusing on rough surfaces (e.g. uncoated paper). We derive a measurement equation that may be used to deduce the point spread function (PSF) of subsurface light transport. Main contributions are the usage of spectrally-narrowband exchangeable LEDs allowing spectrally-resolved measurements and an approach based on quadratic programming for reconstructing PSFs in the case of isotropic light transport.

Herrmann, Daniel; Turba, Martin; Kuijper, Arjan; Schweizer, Immanuel

Inbound Interdomain Traffic Engineering with LISP

2014

Aschenbruck, Nils (Ed.) et al.: Proceedings of the 39th Annual IEEE Conference on Local Computer Networks : LCN 2014. New York: IEEE, Inc., 2014, pp. 458-461

Annual IEEE Conference on Local Computer Networks (LCN) <39, 2014, Edmonton, Canada>

Stub autonomous systems usually utilize multiple links to single or multiple ISPs. Today, inbound traffic engineering is considered hard, as there is no direct way to influence routing decisions on remote systems with BGP. Current traffic engineering methods built on top of BGP are heuristic and time-consuming. The Locator/Identifier Separation Protocol (LISP) promises to change that. In this paper, we conduct the first comprehensive evaluation of LISP and its built-in traffic engineering methods on a real-world testbed. First, we compare LISP to plain BGP and BGP advertising more specific prefixes. This comparison shows that LISP allows effective load-balancing with an accuracy of approximately 5%, while being easier to configure than BGP and its variants. Further experiments show that these results are independent from the number of concurrent streams.

Heß, Martin; Bremm, Sebastian; Weissgraeber, Stephanie; Hamacher, Kay; Goesele, Michael; Wiemeyer, Josef; Landesberger, Tatiana von

Visual Exploration of Parameter Influence on Phylogenetic Trees

2014

IEEE Computer Graphics and Applications, Vol.34 (2014), 2, pp. 48-56

Evolutionary relationships between organisms are represented as phylogenetic trees inferred from multiple sequence alignments (MSAs). The proposed approach clusters trees created with many MSA parameterizations. It displays the chosen parameters' impact on the phylogenetic trees. This view offers interactive parameter exploration and automatic identication of relevant parameters.

Jung, Florian; Steger, Sebastian; Knapp, Oliver; Noll, Matthias; Wesarg, Stefan

COSMO - Coupled Shape Model for Radiation Therapy Planning of Head and Neck Cancer

2014

Linguraru, Marius George (Ed.) et al.: Clinical Image-Based Procedures. Translational Research in Medical Imaging : Third International Workshop, CLIP 2014. Held in Conjunction with MICCAI 2014. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8680), pp. 25-32

International Workshop on Clinical Image-based Procedures (CLIP) <3, 2014, Boston, MA, USA>

Radiation therapy plays a major role in head and neck cancer treatment. Segmentation of organs at risk prior to the radiation therapy helps to prevent the radiation beam from damaging healthy tissue, whereas a concentrated ray can target the cancerous regions. Unfortunately, the manual annotation of all relevant structures in the head and neck area is very time-consuming and existing atlas-based solutions don't provide sufficient segmentation accuracy. Therefore, we propose a coupled shape model (CoSMo) for the segmentation of key structures within the head and neck area. The model's adaptation to a test image is done with respect to the appearance of its items and the trained articulation space. 40 data sets labeled by clinicians containing 22 structures were used to build the CoSMo. Even on very challenging data sets with unnatural postures, which occur far more often than expected, the model adaptation algorithm succeeds. A first evaluation showed an average directed
Hausdorff distance of 13.22mm and an average DICE overlap of 0.62. Furthermore, we review some of the challenges we encountered during the course of building our model from image data, taken from actual radiation therapy planing cases.

Kahn, Svenja; Haumann, Dominik; Willert, Volker

Hand-Eye Calibration with a Depth Camera: 2D or 3D?

2014

Battiato, Sebastiano (Ed.) et al.: VISAPP 2014 - Volume III : Proceedings of the International Conference on Computer Vision Theory and Applications. SciTePress, 2014, pp. 481-489

International Conference on Computer Vision Theory and Applications (VISAPP) <9, 2014, Lisbon, Portugal>

Real time 3D imaging applications such as on the fly 3D inspection or 3D reconstruction can be created by rigidly coupling a depth camera with an articulated measurement arm or a robot. For such applications, the "hand-eye transformation" between the depth camera and the measurement arm needs to be known. For depth cameras, the hand-eye transformation can either be estimated using 2D images or the 3D measurements captured by the depth camera.

This paper investigates the comparison between 2D image based and 3D measurement based hand-eye-calibration. First, two hand-eye calibration approaches are introduced which differ in the way the camera pose is estimated (either with 2D or with 3D data). The main problem in view of the evaluation is, that the ground truth hand-eye transformation is not available and thus a direct evaluation of the accuracy is not possible. Therefore, we introduce quantitative 2D and 3D error measures that allow for an implicit evaluation of the accuracy of the calibration without explicitly knowing the real ground truth transformation. In view of 3D precision, the 3D calibration approach provides more accurate results on average but requires more manual preparation and much more computation time than the 2D approach.

Knuth, Martin; Altenhofen, Christian; Kuijper, Arjan; Bender, Jan

Efficient Self-Shadowing Using Image-Based Lighting on Glossy Surfaces

2014

Bender, Jan (Ed.) et al.: VMV 2014 : Vision, Modeling, and Visualization. Goslar: Eurographics Association, 2014, pp.159-166

Workshop on Vision, Modeling, and Visualization (VMV) <19, 2014, Darmstadt, Germany>

In this paper we present a novel natural illumination approach for real-time rasterization-based rendering with environment map-based high dynamic range lighting. Our approach allows to use all kinds of glossiness values for surfaces, ranging continuously from completely diffuse up to mirror-like glossiness. This is achieved by combining cosine-based diffuse, glossy and mirror reflection models in one single lighting model. We approximate this model by filter functions, which are applied to the environment map. This results in a fast, image-based lookup for the different glossiness values which gives our technique the high performance that is necessary for real-time rendering. In contrast to existing real-time rasterization-based natural illumination techniques, our method has the capability of handling high gloss surfaces with directional self-occlusion.

While previous works exchange the environment map by virtual point light sources in the whole lighting and shadow computation, we keep the full image information of the environment map in the lighting process and only use virtual point light sources for the shadow computation. Our technique was developed for the usage in real-time virtual prototyping systems for garments since here typically a small scene is lit by a large environment which fulfills the requirements for imagebased lighting. In this application area high performance rendering techniques for dynamic scenes are essential since a physical simulation is usually running in parallel on the same machine. However, also other applications can benefit from our approach.

Koa, Ming Di; Johan, Henry

ESLPV: Enhanced Subsurface Light Propagation Volumes

2014

The Visual Computer, Vol.30 (2014), 6-8, pp. 821-831

Computer Graphics International (CGI) <31, 2014, Sydney, Australia>

In this paper, we present an Enhanced Subsurface Light Propagation Volumes (ESLPV) method for real-time rendering of translucent materials. Our method is an extension of the Subsurface Light Propagation Volumes (SSLPV) technique. We improve the SSLPV by incorporating a single scattering framework that uses the same Spherical Harmonics (SH) storage structure as the SSLPV. The new single scattering technique deposits radiance as SH coefficients during a ray marching procedure. The final result is rendered using a ray tracer with importance sampling along the camera ray. This framework also enables the ESLPV to render refractive objects. In addition, we also propose a distance transform optimization that can remove the unnecessary computations during the propagation cycle of LPV [17] based methods. A hierarchical propagation process is also proposed to render highly translucent materials. Similar to the SSLPV, our ESLPV method contains no precomputations, and has low storage
requirements that is independent of the mesh size.

Kochtchi, Arjtom; Landesberger, Tatiana von; Biemann, Chris

Networks of Names: Visual Exploration and Semi-Automatic Tagging of Social Networks from Newspaper Articles

2014

Computer Graphics Forum, Vol.33 (2014), 3, pp. 211-220

International EuroVis Workshop on Visual Analytics (EuroVA) <5, 2014, Swansea, Wales, UK>

Understanding relationships between people and organizations by reading newspaper articles is difficult to manage for humans due to the large amount of data. To address this problem, we present and evaluate a new visual analytics system, which offers interactive exploration and tagging of social networks extracted from newspapers. For the visual exploration of the network, we extract "interesting" neighbourhoods of nodes, using a new degree of interest (DOI) measure based on edges instead of nodes. It improves the seminal definition of DOI, which we find to produce the same "globally interesting" neighbourhoods in our use case, regardless of the query. Our approach allows answering different user queries appropriately, avoiding uniform search results.

We propose a user-driven pattern-based classifier for discovery and tagging of non-taxonomic semantic relations. Our approach does not require any a-priori user knowledge, such as expertise in syntax or pattern creation. An evaluation shows that our classifier is capable of identifying known lexico-syntactic patterns as well as various domain-specific patters. Our classifier yields good results already with a small amount of training, and continuously improves through user feedback.

We conduct a user study to evaluate whether our visual interactive system has an impact on how users tag relationships, as compared to traditional text-based interfaces. Study results suggest that users of the visual system tend to tag more concisely, avoiding too abstract or overly specific relationship labels.

Lenz, Olav; Keul, Frank; Bremm, Sebastian; Hamacher, Kay; Landesberger, Tatiana von

Visual Analysis of Patterns in Multiple Amino Acid Mutation Graphs

2014

Chen, Min (Ed.) et al.: IEEE Conference on Visual Analytics Science and Technology. Proceedings : VAST 2014. Los Alamitos, Calif.: IEEE Computer Society, 2014, pp. 93-102

IEEE Symposium on Visual Analytics Science and Technology (VAST) <9, 2014, Paris, France>

Proteins are essential parts in all living organisms. They consist of sequences of amino acids. An interaction with reactive agent can stimulate a mutation at a specific position in the sequence. This mutation may set off a chain reaction, which effects other amino acids in the protein. Chain reactions need to be analyzed, as they may invoke unwanted side effects in drug treatment.

A mutation chain is represented by a directed acyclic graph, where amino acids are connected by their mutation dependencies. As each amino acid may mutate individually, many mutation graphs exist. To determine important impacts of mutations, experts need to analyze and compare common patterns in these mutations graphs. Experts, however, lack suitable tools for this purpose.

We present a new system for the search and the exploration of frequent patterns (i.e., motifs) in mutation graphs. We present a fast pattern search algorithm specifically developed for finding biologically relevant patterns in many mutation graphs (i.e., many labeled acyclic directed graphs). Our visualization system allows an interactive exploration and comparison of the found patterns. It enables locating the found patterns in the mutation graphs and in the 3D protein structures. In this way, potentially interesting patterns can be discovered. These patterns serve as starting point for a further biological analysis.

In cooperation with biologists, we use our approach for analyzing a real world data set based on multiple HIV protease sequences.

Liu, Yisi; Sourina, Olga

EEG-based Subject-Dependent Emotion Recognition Algorithm Using Fractal Dimension

2014

Institute of Electrical and Electronics Engineers (IEEE): Proceedings 2014 IEEE International Conference on Systems, Man, and Cybernetics : SMC. New York: Curran Associates, 2014, pp. 3166-3171

IEEE International Conference on Systems, Man and Cybernetics (SMC) <2014, San Diego, CA, USA>

In this paper, a real-time Electroencephalogram (EEG)-based emotion recognition algorithm using Higuchi Fractal Dimension (FD) Spectrum is proposed. As EEG is a nonlinear and multi-fractal signal, its FD spectrum can give a better understanding of the nonlinear property of EEG. Three values are selected from the whole spectrum and are combined with the other features such as statistical and Higher Order Crossings ones. The Support Vector Machine is used as the classifier. The proposed algorithm is validated on both benchmark database DEAP with video stimuli and our own dataset which used visual stimuli to evoke emotions. Up to 8 emotions can be recognized with only 4 channels. The experiment analysis results show that using FD spectrum features it is possible to improve classification accuracy.

Nazemi, Kawa; Kuijper, Arjan; Hutter, Marco; Kohlhammer, Jörn; Fellner, Dieter W.

Measuring Context Relevance for Adaptive Semantics Visualizations

2014

Lindstaedt, Stefanie (Ed.) et al.: i-KNOW 2014. Proceedings : 14th International Conferences on Knowledge Management and Knowledge Technologies. New York: ACM, 2014. (ACM International Conference Proceedings Series 889), 8 p.

International Conference on Knowledge Management and Knowledge Technologies (I-KNOW) <14, 2014, Graz, Austria>

Semantics visualizations enable the acquisition of information to amplify the acquisition of knowledge. The dramatic increase of semantics in form of Linked Data and Linked-Open Data yield search databases that allow to visualize the entire context of search results. The visualization of this semantic context enables one to gather more information at once, but the complex structures may as well confuse and frustrate users. To overcome the problems, adaptive visualizations already provide some useful methods to adapt the visualization on users' demands and skills. Although these methods are very promising, these systems do not investigate the relevance of semantic neighboring entities that commonly build most information value. We introduce two new measurements for the relevance of neighboring entities: The Inverse Instance Frequency allows weighting the relevance of semantic concepts based on the number of their instances. The Direct Relation Frequency inverse Relations
Frequency measures the relevance of neighboring instances by the type of semantic relations. Both measurements provide a weighting of neighboring entities of a selected semantic instance, and enable an adaptation of retinal variables for the visualized graph. The algorithms can easily be integrated into adaptive visualizations and enhance them with the relevance measurement of neighboring semantic entities. We give a detailed description of the algorithms to enable a replication for the adaptive and semantics visualization community. With our method, one can now easily derive the relevance of neighboring semantic entities of selected instances, and thus gain more information at once, without confusing and frustrating users.

Nazemi, Kawa; Retz, Wilhelm; Kohlhammer, Jörn; Kuijper, Arjan

User Similarity and Deviation Analysis for Adaptive Visualizations

2014

Yamamoto, Sakae (Ed.): Human Interface and the Management of Information. Proceedings Part I : Information and Interaction for Learning, Culture, Collaboration and Business.. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8521), pp. 64-75

International Conference on Human Interface and the Management of Information (HIMI) <2014, Heraklion, Crete, Greece>

Adaptive visualizations support users in information acquisition and exploration and therewith in human access of data. Their adaptation effect is often based on approaches that require the training by an expert. Further the effects often aim to support just the individual aptitudes. This paper introduces an approach for modeling a canonical user that makes the predefined training-files dispensable and enables an adaptation of visualizations for the majority of users. With the introduced user deviation algorithm, the behavior of individuals can be compared to the average user behavior represented in the canonical user model to identify behavioral anomalies. The further introduced similarity measurements allow to cluster similar deviated behavioral patterns as groups and provide them effective visual adaptations.

Oyarzun Laura, Cristina; Drechsler, Klaus; Wesarg, Stefan

Anatomical Discovery: Finding Organs in the Neighborhood of the Liver

2014

Romero, Laura M. Roa (Ed.): XIII Mediterranean Conference on Medical and Biological Engineering and Computing : MEDICON 2013. Berlin, Heidelberg, New York: Springer, 2014. (IFMBE Proceedings 41), pp. 348-351

The Mediterranean Conference on Medical and Biological Engineering and Computing (MEDICON) <13, 2013, Seville, Spain>

Image segmentation and registration algorithms are fundamental to assist medical doctors for better treatment of the patients. To this end accuracy in the results given by those algorithms is crucial. The surroundings of the organ to be segmented or registered can provide additional information that at the end improves the result. In this paper a novel algorithm to detect the organs that surround the liver is introduced. Even though our work is focused on the liver, the algorithm could be extended to other parts of the body. The algorithm has been tested in 24 clinical CT datasets. In addition to this, an example application is introduced for which the detection is a useful tool.

Preiss, Jens; Fernandes, Felipe; Urban, Philipp

Color-Image Quality Assessment: From Prediction to Optimization

2014

IEEE Transactions on Image Processing, Vol.23 (2014), 3, pp. 1366-1378

While image-difference metrics show good prediction performance on visual data, they often yield artifact-contaminated results if used as objective functions for optimizing complex image-processing tasks. We investigate in this regard the recently proposed color-image-difference (CID) metric particularly developed for predicting gamut-mapping distortions. We present an algorithm for optimizing gamut mapping employing the CID metric as the objective function. Resulting images contain various visual artifacts, which are addressed by multiple modifications yielding the improved color-image-difference (iCID) metric. The iCID-based optimizations are free from artifacts and retain contrast, structure, and color of the original image to a great extent. Furthermore, the prediction performance on visual data is improved by the modifications.

Ruppert, Tobias; Bernard, Jürgen; Ulmer, Alex; Lücke-Tieke, Hendrik; Kohlhammer, Jörn

Visual Access to an Agent-based Simulation Model to Support Political Decision Making

2014

Lindstaedt, Stefanie (Ed.) et al.: i-KNOW 2014. Proceedings : 14th International Conferences on Knowledge Management and Knowledge Technologies. New York: ACM, 2014. (ACM International Conference Proceedings Series 889), 8 p.

International Conference on Knowledge Management and Knowledge Technologies (I-KNOW) <14, 2014, Graz, Austria>

Decision making in the field of policy making is a complex task. On the one hand conflicting objectives influence the availability of alternative solutions for a given problem. On the other hand economic, social, and environmental impacts of the chosen solution have to be considered. In the political context, these solutions are called policy options. To tackle societal problems a thorough analysis of policy options needs to be executed before a policy can be put into practice. Computational simulation is a method considered for measuring the impacts of policy options. However, due to their complexity, the underlying models and their output may be difficult to access by decision makers. In this work, we present a visual-interactive interface for an agent-based simulation model that enables decision makers to evaluate the impacts of alternative policy options in the field of regional energy planning. The decision maker can specify different subsidy strategies for supporting
public photovoltaic installations as input and evaluate their impact on the actual adoption via the simulation output. We show the usability and usefulness of the visual interface in a real-world example evolved from the European research project ePolicy.

Rus, Silvia; Große-Puppendahl, Tobias; Kuijper, Arjan

Recognition of Bed Postures Using Mutual Capacitance Sensing

2014

Aarts, Emile (Ed.) et al.: Ambient Intelligence : European Conference, AmI 2014. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8850), pp. 51-66

European Conference on Ambient Intelligence (AmI) <11, 2014, Eindhoven, The Netherlands>

In recent years, mutual capacitive sensing made significant advances in the field of gathering implicit contextual data. These systems find broad usage in pervasive activity-recognition systems, installed stationary or made portable. In the domain of context recognition new ways of interaction with the environment opened up since conductive objects can be detected under certain conditions at distances up to 50 cm.

This paper investigates an approach to recognize bed postures using mutual capacitance sensing. The overall goal is to develop a technological concept that can be applied to recognize bed postures of patients in elderly homes. The use of this contextual data may lead to many desired benefits in elderly care e.g. the better prevention of decubitus ulcer, a condition caused by prolonged pressure on the skin resulting in injuries to skin and underlying tissues. For this, we propose a low-cost grid of crossed wires of 48 measurement points placed between the mattress and the bed sheet. The experimental results analyze a set of five lying positions. We achieved for all tested individuals an accuracy of 80.76% and for several individuals of the same bodysize an accuracy of 93.8%.

Santos, Pedro; Ritz, Martin; Tausch, Reimar; Schmedt, Hendrik; Monroy Rodriguez, Rafael; Stefano, Antonio; Posniak, Oliver; Fuhrmann, Constanze; Fellner, Dieter W.

CultLab3D - On the Verge of 3D Mass Digitization

2014

Klein, Reinhard (Ed.) et al.: GCH 2014 : Eurographics Workshop on Graphics and Cultural Heritage. Goslar: Eurographics Association, 2014, pp. 65-73

Eurographics Symposium on Graphics and Cultural Heritage (GCH) <12, 2014, Darmstadt, Germany>

Acquisition of 3D geometry, texture and optical material properties of real objects still consumes a considerable amount of time, and forces humans to dedicate their full attention to this process. We propose CultLab3D, an automatic modular 3D digitization pipeline, aiming for efficient mass digitization of 3D geometry, texture, and optical material properties. CultLab3D requires minimal human intervention and reduces processing time to a fraction of today's efforts for manual digitization. The final step in our digitization workflow involves the integration of the digital object into enduring 3D Cultural Heritage Collections together with the available semantic information related to the object. In addition, a software tool facilitates virtual, location-independent analysis and publication of the virtual surrogates of the objects, and encourages collaboration between scientists all around the world. The pipeline is designed in a modular fashion and allows for further extensions
to incorporate newer technologies. For instance, by switching scanning heads, it is possible to acquire coarser or more refined 3D geometry.

Schiffer, Thomas; Fellner, Dieter W.

Efficient Multi-kernel Ray Tracing for GPUs

2014

Coquillart, Sabine (Ed.) et al.: GRAPP 2014 : Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications. SciTePress, 2014, pp. 209-217

International Conference on Computer Graphics Theory and Applications (GRAPP) <9, 2014, Lisbon, Portugal>

Images with high visual quality are often generated by a ray tracing algorithm. Despite its conceptual simplicity, designing an efficient mapping of ray tracing computations to massively parallel hardware architectures is a challenging task. In this paper we investigate the performance of state-of-the-art ray traversal algorithms for bounding volume hierarchies on GPUs and discuss their potentials and limitations. Based on this analysis, a novel ray traversal scheme called batch tracing is proposed. It decomposes the task into multiple kernels, each of which is designed for efficient parallel execution. Our algorithm achieves comparable performance to currently prevailing approaches and represents a promising avenue for future research.

Schinko, Christoph; Berndt, Rene; Eggeling, Eva; Fellner, Dieter W.

A Scalable Rendering Framework for Generative 3D Content

2014

Polys, Nicholas F. (General Chair) et al.: Proceedings Web3D 2014 : 19th International Conference on 3D Web Technology. New York: ACM, 2014, pp. 81-87

International Conference on 3D Web Technology (WEB3D) <19, 2014, Vancouver, BC, Canada>

Delivering high quality 3D content through a web browser is still a challenge especially when intellectual property (IP) protection is necessary. Thus, the transfer of 3D modeling information to a client should be avoided. In our work we present a solution to this problem by introducing a server-side rendering framework. Only images are transferred to the client, the actual 3D content is not delivered. By providing simple proxy geometry it is still possible to provide direct interaction on the client.

Our framework incorporates the Generative Modeling Language (GML) for the description and rendering of generative content. It is then possible to not only interact with the 3D content, but to modify the actual shape within the possibilities of the generative content. By introducing a control layer and encapsulating processing and rendering of the generative content in a so called GML Rendering Unit (GRU) it is possible to provide a scalable rendering framework.

Schmidt, Uwe; Roth, Stefan

Shrinkage Fields for Effective Image Restoration

2014

IEEE Computer Society: 2014 IEEE Conference on Computer Vision and Pattern Recognition. Proceedings : CVPR 2014. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2014, pp. 2774-2781

IEEE Conference on Computer Vision and Pattern Recognition (CVPR) <32, 2014, Columbus, Ohio, USA>

Many state-of-the-art image restoration approaches do not scale well to larger images, such as megapixel images common in the consumer segment. Computationally expensive optimization is often the culprit. While efficient alternatives exist, they have not reached the same level of image quality. The goal of this paper is to develop an effective approach to image restoration that offers both computational efficiency and high restoration quality. To that end we propose shrinkage fields, a random field-based architecture that combines the image model and the optimization algorithm in a single unit. The underlying shrinkage operation bears connections to wavelet approaches, but is used here in a random field context. Computational efficiency is achieved by construction through the use of convolution and DFT as the core components; high restoration quality is attained through loss-based training of all model parameters and the use of a cascade architecture. Unlike heavily engineered
solutions, our learning approach can be adapted easily to different trade-offs between efficiency and image quality. We demonstrate state-of-the-art restoration results with high levels of computational efficiency, and significant speedup potential through inherent parallelism.

Steiger, Martin; Bernard, Jürgen; Mittelstädt, Sebastian; Lücke-Tieke, Hendrik; Keim, Daniel A.; May, Thorsten; Kohlhammer, Jörn

Visual Analysis of Time-Series Similarities for Anomaly Detection in Sensor Networks

2014

Computer Graphics Forum, Vol.33 (2014), 3, pp. 401-410

Eurographics Conference on Visualization (EuroVis) <16, 2014, Swansea, Wales, UK>

We present a system to analyze time-series data in sensor networks. Our approach supports exploratory tasks for the comparison of univariate, geo-referenced sensor data, in particular for anomaly detection. We split the recordings into fixed-length patterns and show them in order to compare them over time and space using two linked views. Apart from geo-based comparison across sensors we also support different temporal patterns to discover seasonal effects, anomalies and periodicities.

The methods we use are best practices in the information visualization domain. They cover the daily, the weekly and seasonal and patterns of the data. Daily patterns can be analyzed in a clustering-based view, weekly patterns in a calendar-based view and seasonal patterns in a projection-based view. The connectivity of the sensors can be analyzed through a dedicated topological network view. We assist the domain expert with interaction techniques to make the results understandable. As a result, the user can identify and analyze erroneous and suspicious measurements in the network. A case study with a domain expert verified the usefulness of our approach.

Stenin, Igor; Hansen, Stefan; Becker, Meike; Sakas, Georgios; Fellner, Dieter W.; Klenzner, Thomas; Schipper, Jörg

Minimally Invasive Multiport Surgery of the Lateral Skull Base

2014

BioMed Research International, Vol.2014 (2014), Article ID 379295, 7 p.

Objective: Minimally invasive procedures minimize iatrogenic tissue damage and lead to a lower complication rate and high patient satisfaction. To date only experimental minimally invasive single-port approaches to the lateral skull base have been attempted. The aim of this study was to verify the feasibility of a minimally invasive multiport approach for advanced manipulation capability and visual control and develop a software tool for preoperative planning.

Methods: Anatomical 3D models were extracted from twenty regular temporal bone CT scans. Collision-free trajectories, targeting the internal auditory canal, round window, and petrous apex, were simulated with a specially designed planning software tool. A set of three collision-free trajectories was selected by skull base surgeons concerning the maximization of the distance to critical structures and the angles between the trajectories.

Results: A set of three collision-free trajectories could be successfully simulated to the three targets in each temporal bone model without violating critical anatomical structures.

Conclusion: A minimally invasive multiport approach to the lateral skull base is feasible. The developed software is the first step for preoperative planning. Further studies will focus on cadaveric and clinical translation.

Ullrich, Torsten; Fellner, Dieter W.

Statistical Analysis on Global Optimization

2014

MCSI 2014 : 2014 International Conference on Mathematics and Computers in Sciences and in Industry. Los Alamitos, Calif.: IEEE Computer Society Conference Publishing Services (CPS), 2014, pp. 99-106

International Conference on Mathematics and Computers in Sciences and in Industry (MCSI) <2014, Varna, Bulgaria>

The global optimization of a mathematical model determines the best parameters such that a target or cost function is minimized. Optimization problems arise in almost all scientific disciplines (operations research, life sciences, etc.). Only in a few exceptional cases, these problems can be solved analytically-exactly, so in practice numerical routines based on approximations have to be used. The routines return a result - a so-called candidate of a global minimum. Unfortunately, the question whether the candidate represents the optimal solution, often remains unanswered. This article presents a simple-to-use, statistical analysis that determines and assesses the quality of such a result. This information is valuable and important - especially for practical application.

Vogel, Christoph; Roth, Stefan; Schindler, Konrad

View-Consistent 3D Scene Flow Estimation over Multiple Frames

2014

Fleet, David (Ed.) et al.: Computer Vision - ECCV 2014. Proceedings Part IV : 13th European Conference on Computer Vision. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8692), pp. 263-278

European Conference on Computer Vision (ECCV) <13, 2014, Zurich, Switzerland>

We propose a method to recover dense 3D scene flow from stereo video. The method estimates the depth and 3D motion field of a dynamic scene from multiple consecutive frames in a sliding temporal window, such that the estimate is consistent across both viewpoints of all frames within the window. The observed scene is modeled as a collection of planar patches that are consistent across views, each undergoing a rigid motion that is approximately constant over time. Finding the patches and their motions is cast as minimization of an energy function over the continuous plane and motion parameters and the discrete pixel-to-plane assignment. We show that such a view-consistent multi-frame scheme greatly improves scene flow computation in the presence of occlusions, and increases its robustness against adverse imaging conditions, such as specularities. Our method currently achieves leading performance on the KITTI benchmark, for both flow and stereo.

Weber, Daniel; Mueller-Roemer, Johannes; Altenhofen, Christian; Stork, André; Fellner, Dieter W.

A p-Multigrid Algorithm using Cubic Finite Elements for Efficient Deformation Simulation

2014

Bender, Jan (Ed.) et al.: VRIPHYS 14: 11th Workshop in Virtual Reality Interactions and Physical Simulations. Goslar: Eurographics Association, 2014, pp. 49-58

International Workshop in Virtual Reality Interaction and Physical Simulations (VRIPHYS) <11, 2014, Bremen, Germany>

We present a novel p-multigrid method for efficient simulation of co-rotational elasticity with higher-order finite elements. In contrast to other multigrid methods proposed for volumetric deformation, the resolution hierarchy is realized by varying polynomial degrees on a tetrahedral mesh. We demonstrate the efficiency of our approach and compare it to commonly used direct sparse solvers and preconditioned conjugate gradient methods. As the polynomial representation is defined w.r.t. the same mesh, the update of the matrix hierarchy necessary for co-rotational elasticity can be computed efficiently. We introduce the use of cubic finite elements for volumetric deformation and investigate different combinations of polynomial degrees for the hierarchy. We analyze the applicability of cubic finite elements for deformation simulation by comparing analytical results in a static scenario and demonstrate our algorithm in dynamic simulations with quadratic and cubic elements. Applying
our method to quadratic and cubic finite elements results in speed up of up to a factor of 7 for solving the linear system.

Wächter, Michael; Moehrle, Nils; Goesele, Michael

Let There Be Color! Large-Scale Texturing of 3D Reconstructions

2014

Fleet, David (Ed.) et al.: Computer Vision - ECCV 2014. Proceedings Part V : 13th European Conference on Computer Vision. Berlin, Heidelberg, New York: Springer, 2014. (Lecture Notes in Computer Science (LNCS) 8693), pp. 836-850

European Conference on Computer Vision (ECCV) <13, 2014, Zurich, Switzerland>

3D reconstruction pipelines using structure-from-motion and multi-view stereo techniques are today able to reconstruct impressive, large-scale geometry models from images but do not yield textured results. Current texture creation methods are unable to handle the complexity and scale of these models. We therefore present the first comprehensive texturing framework for large-scale, real-world 3D reconstructions. Our method addresses most challenges occurring in such reconstructions: the large number of input images, their drastically varying properties such as image scale, (out-of-focus) blur, exposure variation, and occluders (e.g., moving plants or pedestrians). Using the proposed technique, we are able to texture datasets that are several orders of magnitude larger and far more challenging than shown in related work.