78 research outputs found
Skeletonization and segmentation of binary voxel shapes
No full textPreface. This dissertation is the result of research that I conducted between January 2005 and December 2008 in the Visualization research group of the Technische Universiteit Eindhoven. I am pleased to have the opportunity to thank a number of people that made this work possible. I owe my sincere gratitude to Alexandru Telea, my supervisor and first promotor. I did not consider pursuing a PhD until my Master’s project, which he also supervised. Due to our pleasant collaboration from which I learned quite a lot, I became convinced that becoming a doctoral student would be the right thing to do for me. Indeed, I can say it has greatly increased my knowledge and professional skills. Alex, thank you for our interesting discussions and the freedom you gave me in conducting my research. You made these four years a pleasant experience. I am further grateful to Jack vanWijk, my second promotor. Our monthly discussions were insightful, and he continuously encouraged me to take a more formal and scientific stance. I would also like to thank Prof. Jan de Graaf from the department of mathematics for our discussions on some of my conjectures. His mathematical rigor was inspiring. I am greatly indebted to the Netherlands Organisation for Scientific Research (NWO) for funding my PhD project (grant number 612.065.414). I thank Prof. Kaleem Siddiqi, Prof. Mark de Berg, and Dr. Remco Veltkamp for taking part in the core doctoral committee and Prof. Deborah Silver and Prof. Jos Roerdink for participating in the extended committee. Our Visualization group provides a great atmosphere to do research in. In particular, I would like to thank my fellow doctoral students Frank van Ham, Hannes Pretorius, Lucian Voinea, Danny Holten, Koray Duhbaci, Yedendra Shrinivasan, Jing Li, NielsWillems, and Romain Bourqui. They enabled me to take my mind of research from time to time, by discussing political and economical affairs, and more trivial topics. Furthermore, I would like to thank the senior researchers of our group, Huub van de Wetering, Kees Huizing, and Michel Westenberg. In particular, I thank Andrei Jalba for our fruitful collaboration in the last part of my work. On a personal level, I would like to thank my parents and sister for their love and support over the years, my friends for providing distractions outside of the office, and Michelle for her unconditional love and ability to light up my mood when needed
A Tool for Optimizing the Build Performance of Large Software Code Bases
No full textWe present Build Analyzer, a tool that helps developers optimize the build performance of huge systems written in C. Due to complex C header dependencies, even small code changes can cause extremely long rebuilds, which are problematic when code is shared and modified by teams of hundreds of individuals. Build Analyzer supports several use cases. For developers, it provides an estimate of the build impact and distribution caused by a given change. For architects, it shows why a build is costly, how its cost is spread over the entire code base, which headers cause build bottlenecks, and suggests ways to refactor these to reduce the cost. We demonstrate Build Analyzer with a use-case on a real industry code base.
Combining Extended Table Lens and Treemap Techniques for Visualizing Tabular Data
No full textWe present a framework for visualizing large tabular data that combines two views: the table view and the treemap view. The table view extends the known table lens as follows: We cluster related elements to reduce subsampling artifacts and achieve table size independent rendering time; we use multiple-column sorting to create scenario-specific data hierarchies on the fly; and we use shaded cushions to show data structure and variation. Hierarchies built in the table view are shown in a customizable treemap view. One can choose both layout and rendering by a few clicks, effectively creating visual scenarios on-the-fly. We illustrate our framework on real-life stock data.
Combining Object Orientation and Dataflow Modeling in the VISSION Simulation System
No full textScientific visualization and simulation frameworks mostly use data/event flow mechanisms for simulation specification, control, and interactivity. Even though object orientation powerfully and elegantly models many application domains, integration of OO libraries in such systems remains difficult. The elegance and simplicity of OO design gets lost in the integration phase, as most systems do not support combination of OO and dataflow concepts. We propose a general-purpose OO visualization and simulation system which addresses simulation design, control and interactivity by merging OO and dataflow modelling in a single abstraction. The system’s advantages over similar ones are illustrated by a comprehensive setofexamples.
A Component-Based Dataflow Framework for Simulation and Visualization
No full textReuse in the context of scientific simulation applications has mostly taken the form of procedural or object-oriented libraries. End users of such systems are however often non software experts needing very simple, possibly interactive ways to build applications from domain-specific components and to control their parameters. Integrating independently written (existing or new) code as components should ideally be a simple, possibly automated black-box process. We propose a dataflow-based component framework for simulation and visualization in which large existing C++ application libraries were easily integrated as interactively manipulable components by using a meta-layer object-oriented component abstraction. The path from user-level requirements to the framework design and implementation decisions is outlined.
Visualisation and simulation with object-oriented networks
No full textAmong the existing systems, visual programming environments address best these issues. However, producing interactive simulations and visualisations is still a difficult task. This defines the main research objective of this thesis: The development and implementation of concepts and techniques to combine visualisation, simulation, and application construction in an interactive, easy to use, generic environment. The aim is to produce an environment in which the above mentioned activities can be learnt and carried out easily by a researcher. Working with such an environment should decrease the amount of time usually spent in redesigning existing software elements such as graphics interfaces, existing computational modules, and general infrastructure code. Writing new computational components or importing existing ones should be simple and automatic enough to make using the envisaged system an attractive option for a non programmer expert. Besides this, all proven successful elements of an interactive simulation and visualisation environment should be provided, such as visual programming, graphics user interfaces, direct manipulation, and so on. Finally, a large palette of existing scientific computation, data processing, and visualisation components should be integrated in the proposed system. On one hand, this should prove our claims of openness and easy code integration. On the other hand, this should provide the concrete set of tools needed for building a range of scientific applications and visualisations. This thesis is structured as follows. Chapter 2 defines the context of our work. The scientific research environment is presented and partitioned into the three roles of end user, application designer, and component developer. The interactions between these roles and their specific requirements are described and lead to a more precise formulation of our problem statement. Chapter 3 presents the most used architectures for simulation and visualisation systems: the monolithic system, the application library, and the framework. The advantages and disadvantages of these architectural models are then discussed in relation with our problem statement requirements. The main conclusion drawn is that no single existing architectural model suffices, and that what is needed is a combination of the features present in all three models. Chapter 4 introduces the new architectural model we propose, based on the combination of object-orientation in form of the C++ language and dataflow modelling in the new MC++ language. Chapter 5 presents VISSION, an interactive simulation and visualisation environment constructed on the introduced new architectural model, and shows how the usual tasks of application construction, steering, and visualisation are addressed. In chapter 6, the implementation of VISSIONis architectural model is described in terms of its component parts. Chapter 7 presents the applications of VISSION to numerical simulation, while chapter 8 focuses on its visualisation and graphics applications. Finally, chapter 9 concludes the thesis and outlines possible direction for future research
Voxel-based assessment of printability of 3D shapes
No full textPrintability, the capability of a 3D printer to closely reproduce a 3D model, is a complex decision involving several geometrical attributes like local thickness, shape of the thin regions and their surroundings, and topology with respect to thin regions. We present a method for assessment of 3D shape printability which efficiently and effectively computes such attributes. Our method uses a simple and efficient voxel-based representation and associated computations. Using tools from multi-scale morphology and geodesic analysis, we propose several new metrics for various printability problems. We illustrate our method with results taken from a real-life application
Probabilistic View-based 3D Curve Skeleton Computation on the GPU
No full textComputing curve skeletons of 3D shapes is a challenging task. Recently, a high-potential technique for this task was proposed, based on integrating medial information obtained from several 2D projections of a 3D shape. However effective, this technique is strongly influenced in terms of complexity by the quality of a so-called skeleton probability volume, which encodes potential 3D curve-skeleton locations. In this paper, we extend the above method to deliver a highly accurate and discriminative curve-skeleton probability volume. For this, we analyze the error sources of the original technique, and propose improvements in terms of accuracy, culling false positives, and speed. We show that our technique can deliver point-cloud curve-skeletons which are close to the desired locations, even in the absence of complex postprocessing. We demonstrate our technique on several 3D models.
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