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- Augmented Reality (8)
- Computergrafik (8)
- Computervisualistik (7)
- GPGPU (5)
- Raytracing (5)
- Android (4)
- Computergraphik (4)
- Line Space (4)
- OpenGL (4)
- Analyse durch Synthese (3)
Institute
Artificial neural networks is a popular field of research in artificial intelli-
gence. The increasing size and complexity of huge models entail certain
problems. The lack of transparency of the inner workings of a neural net-
work makes it difficult to choose efficient architectures for different tasks.
It proves to be challenging to solve these problems, and with a lack of in-
sightful representations of neural networks, this state of affairs becomes
entrenched. With these difficulties in mind a novel 3D visualization tech-
nique is introduced. Attributes for trained neural networks are estimated
by utilizing established methods from the area of neural network optimiza-
tion. Batch normalization is used with fine-tuning and feature extraction to
estimate the importance of different parts of the neural network. A combi-
nation of the importance values with various methods like edge bundling,
ray tracing, 3D impostor and a special transparency technique results in a
3D model representing a neural network. The validity of the extracted im-
portance estimations is demonstrated and the potential of the developed
visualization is explored.
In this thesis the possibilities for real-time visualization of OpenVDB
files are investigated. The basics of OpenVDB, its possibilities, as well
as NanoVDB and its GPU port, were studied. A system was developed
using PNanoVDB, the graphics API port of OpenVDB. Techniques were
explored to improve and accelerate a single ray approach of ray tracing.
To prove real-time capability, two single scattering approaches were
also implemented. One of these was selected, further investigated and
optimized to achieve interactive real-time rendering.
It is important to give artists immediate feedback on their adjustments, as
well as the possibility to change all parameters to ensure a user friendly
creation process.
In addition to the optical rendering, corresponding benchmarks were
collected to compare different improvement approaches and to prove
their relevance. Attention was paid to the rendering times and memory
consumption on the GPU to ensure optimal use. A special focus, when
rendering OpenVDB files, was put on the integrability and extensibility of
the program to allow easy integration into an existing real-time renderer
like U-Render.
Virtual reality is a growing field of interest as it provides a particular intuitive way of user-interaction. However, there are still open technical issues regarding latency — the delay between interaction and display reaction — and the trade-off between visual quality and frame-rate of real-time graphics, especially when taking visual effects like specular and semi-transparent surfaces and volumes into account. One solution, a distributed rendering setup, is presented in this thesis, in which the image synthesis is divided into an accurate but costly physically based rendering thread with a low refresh rate and a fast reprojection thread to remain a responsive interactivity with a high frame-rate. Two novel reprojection techniques are proposed that cover reflections and refractions produced by surface ray-tracing as well as volumetric light transport generated by volume ray-marching. The introduced setup can enhance the VR experience within several domains. In this thesis, three innovative training applications have been realized to investigate the added value of virtual reality to the three learning stages of observation, interaction and collaboration. For each stage an interdisciplinary curriculum, currently taught with traditional media, was transferred to a VR setting in order to investigate how virtual reality is capable of providing a natural, flexible and efficient learning environment
Augmented reality (AR) applications typically extend the user's view of the real world with virtual objects.
In recent years, AR has gained increasing popularity and attention, which has led to improvements in the required technologies. AR has become available to almost everyone.
Researchers have made great progress towards the goal of believable AR, in which the real and virtual worlds are combined seamlessly.
They mainly focus on issues like tracking, display technologies and user interaction, and give little attention to visual and physical coherence when real and virtual objects are combined. For example, virtual objects should not only respond to the user's input; they should also interact with real objects. Generally, AR becomes more believable and realistic if virtual objects appear fixed or anchored in the real scene, appear indistinguishable from the real scene, and response to any changes within it.
This thesis examines on three challenges in the field of computer vision to meet the goal of a believable combined world in which virtual objects appear and behave like real objects.
Firstly, the thesis concentrates on the well-known tracking and registration problem. The tracking and registration challenge is discussed and an approach is presented to estimate the position and viewpoint of the user so that virtual objects appear fixed in the real world. Appearance-based line models, which keep only relevant edges for tracking purposes, enable absolute registration in the real world and provide robust tracking. On the one hand, there is no need to spend much time creating suitable models manually. On the other hand, the tracking can deal with changes within the object or the scene to be tracked. Experiments have shown that the use of appearance-based line models improves the robustness, accuracy and re-initialization speed of the tracking process.
Secondly, the thesis deals with the subject of reconstructing the surface of a real environment and presents an algorithm to optimize an ongoing surface reconstruction. A complete 3D surface reconstruction of the target scene
offers new possibilities for creating more realistic AR applications. Several interactions between real and virtual objects, such as collision and occlusions, can be handled with physical correctness. Whereas previous methods focused on improving surface reconstructions offline after a capturing step, the presented method de-noises, extends and fills holes during the capturing process. Thus, users can explore an unknown environment without any preparation tasks such as moving around and scanning the scene, and without having to deal with the underlying technology in advance. In experiments, the approach provided realistic results where known surfaces were extended and filled in plausibly for different surface types.
Finally, the thesis focuses on handling occlusions between the real and virtual worlds more realistically, by re-interpreting the occlusion challenge as an alpha matting problem. The presented method overcomes limitations in state-of-the-art methods by estimating a blending coefficient per pixel of the rendered virtual scene, instead of calculating only their visibility. In several experiments and comparisons with other methods, occlusion handling through alpha matting worked robustly and overcame limitations of low-cost sensor data; it also outperformed previous work in terms of quality, realism and practical applicability.
The method can deal with noisy depth data and yields realistic results in regions where foreground and background are not strictly separable (e.g. caused by fuzzy objects or motion blur).
Ray tracing acceleration through dedicated data structures has long been an important topic in computer graphics. In general, two different approaches are proposed: spatial and directional acceleration structures. The thesis at hand presents an innovative combined approach of these two areas, which enables a further acceleration of the tracing process of rays. State-of-the-art spatial data structures are used as base structures and enhanced by precomputed directional visibility information based on a sophisticated abstraction concept of shafts within an original structure, the Line Space.
In the course of the work, novel approaches for the precomputed visibility information are proposed: a binary value that indicates whether a shaft is empty or non-empty as well as a single candidate approximating the actual surface as a representative candidate. It is shown how the binary value is used in a simple but effective empty space skipping technique, which allows a performance gain in ray tracing of up to 40% compared to the pure base data structure, regardless of the spatial structure that is actually used. In addition, it is shown that this binary visibility information provides a fast technique for calculating soft shadows and ambient occlusion based on blocker approximations. Although the results contain a certain inaccuracy error, which is also presented and discussed, it is shown that a further tracing acceleration of up to 300% compared to the base structure is achieved. As an extension of this approach, the representative candidate precomputation is demonstrated, which is used to accelerate the indirect lighting computation, resulting in a significant performance gain at the expense of image errors. Finally, techniques based on two-stage structures and a usage heuristic are proposed and evaluated. These reduce memory consumption and approximation errors while maintaining the performance gain and also enabling further possibilities with object instancing and rigid transformations.
All performance and memory values as well as the approximation errors are measured, presented and discussed. Overall, the Line Space is shown to result in a considerate improvement in ray tracing performance at the cost of higher memory consumption and possible approximation errors. The presented findings thus demonstrate the capability of the combined approach and enable further possibilities for future work.
Point Rendering
(2021)
In this thesis different methods for rendering point data are shown and compared with each other. The methods can be divided into two categories. For one visual methods are introduced that strictly deal with the displaying of point primitves. The main problem here lies in the depiction of surfaces since point data, unlike traditional triangle meshes, doesn't contain any connectivity information. On the other hand data strucutres are shown that enable real-time rendering of large point clouds. Point clouds often contain large amounts of data since they are mostly generated through 3D scanning processes such as laser scanning and photogrammetry.
In der Computergrafik stellte die Berechnung von Reflexionen lange ein
Problem dar. Doch mit der ständigen Weiterentwicklung der Hardware
und Vorstellung neuer Verfahren ist eine realitätsnahe,
echtzeitfähige(durchschnittlich 60 FPS) Berechnung von Reflexionen möglich. In der folgenden Ausarbeitung werden verschiedene Reflexionsverfahren vorgestellt. Alle mathematischen und physikalischen Grundlagen werden gegeben, um die Algorithmen nachvollziehen zu können. Da eine Reflexion immer das Abtasten eines reflektierten Vektors bedeutet, werden zwei verschiedene Abtastungsverfahren für blickabhängige Reflexionen vorgestellt und anschließend implementiert. Zuletzt werden die Verfahren auf Basis von Qualität und Performance gegenübergestellt.
In dieser Arbeit wird die Konzeption, Implementierung und Evaluierung einer Augmented Reality-App beschrieben. Diese wurde mit dem Ziel entwickelt, Objekte im realen Raum mit virtuellen Hilfsmitteln auszumessen, sodass diese Anwendung einen Holzgliedermaßstab ersetzen kann. Hinzu kommt die praktische Speicherung der Messwerte. Angefertigt wurde die App mit der Unity Engine und programmiert in C#.
Schwerpunkte dieser Arbeit sind die Benutzerfreundlichkeit der App, sowie die Eignung von AR Foundation für das Ausmessungstool.
Die Anwendung wird auf die genannten Kriterien im Rahmen eines Nutzertests in einer abschließenden Evaluation bewertet.
Als Ergebnis ließ sich festhalten, dass sich die AR-App noch im Prototyp-Stadium befindet, aber im Allgemeinen schon als benutzerfreundlich gilt. Kleinere Änderungen sollen und müssen noch vorgenommen werden, um auch den Umgang mit dem AR-Tool zu vereinfachen.
The Material Point Method (MPM) has proven to be a very capable simulation method in computer graphics that is able to model materials that were previously very challenging to animate [1, 2]. Apart from simulating singular materials, the simulation of multiple materials that interact with each other introduces new challenges. This is the focus of this thesis. It will be shown that the self-collision capabilities of the MPM can naturally handle multiple materials interacting in the same scene on a collision basis, even if the materials use distinct constitutive models. This is then extended by porous interaction of materials as in[3], which also integrates easily with MPM.It will furthermore be shown that regular single-grid MPM can be viewed as a subset of this multi-grid approach, meaning that its behavior can also be achieved if multiple grids are used. The porous interaction is generalized to arbitrary materials and freely changeable material interaction terms, yielding a flexible, user-controllable framework that is independent of specific constitutive models. The framework is implemented on the GPU in a straightforward and simple way and takes advantage of the rasterization pipeline to resolve write-conflicts, resulting in a portable implementation with wide hardware support, unlike other approaches such as [4].
In the context of augmented reality we define tracking as a collection of methods to obtain the position and orientation (pose) of a user. By means of various displaying techniques, this ensures a correct visual overlay of graphical information onto the reality perceived. Precise results for calculation of the camera pose are gained by methods of image processing, usually analyzing the pixels of an image and extracing features, which can be recognized over the image sequence. However, these methods do not regard the process of image synthesis or at least in a very simplyfied way. In contrast, the class of model-based methods assumes a given 3D model of the observed scene. Based on the model data features can be identified to establish correspondences in the camera image. From these feature correspondences the camera pose is calculated. An interesting approach is the strategy of analysis-by-synthesis, regarding the computer graphics rendering process for extending the knowledge about the model by information from image synthesis and other environment variables.
In this thesis the components of a tracking system are identified and further it is analyzed, to what extend information about the model, the rendering process and the environment can contribute to the components for improvement of the tracking process using analysis-by-synthesis. In particular, by using knowledge as topological information, lighting or perspective, the feature synthesis and correspondence finding should lead to visually unambiguous features that can be predicted and evaluated to be suitable for stable tracking of the camera pose.
Molecular dynamics (MD) as a field of molecular modelling has great potential to revolutionize our knowledge and understanding of complex macromolecular structures. Its field of application is huge, reaching from computational chemistry and biology over material sciences to computer-aided drug design. This thesis on one hand provides insights into the underlying physical concepts of molecular dynamics simulations and how they are applied in the MD algorithm, and also briefly illustrates different approaches, as for instance the molecular mechanics and molecular quantum mechanics approaches.
On the other hand an own all-atom MD algorithm is implemented utilizing and simplifying a version of the molecular mechanics based AMBER force field published by \big[\cite{cornell1995second}\big]. This simulation algorithm is then used to show by the example of oxytocin how individual energy terms of a force field function. As a result it has been observed, that applying the bond stretch forces alone caused the molecule to be compacted first in certain regions and then as a whole, and that with adding more energy terms the molecule got to move with increasing flexibility.
Tracking is an integral part of many modern applications, especially in areas like autonomous systems and Augmented Reality. For performing tracking there are a wide array of approaches. One that has become a subject of research just recently is the utilization of Neural Networks. In the scope of this master thesis an application will be developed which uses such a Neural Network for the tracking process. This also requires the creation of training data as well as the creation and training of a Neural Network. Subsequently the usage of Neural Networks for tracking will be analyzed and evaluated. This includes several aspects. The quality of the tracking for different degrees of freedom will be checked as well as the the impact of the Neural Network on the applications performance. Additionally the amount of required training data is investigated, the influence of the network architecture and the importance of providing depth data as part of the networks input. This should provide an insight into how relevant this approach could be for its adoption in future products.
This thesis is about the design and the implementation of a virtual reality experience. The goal is to answer two questions: Is it possible to create an immersive virtual reality experience which is mainly using impulses and triggers to scare and frighten users? Secondly, is this immersion strong enough to create an illusion in which the user can't separate the real world from the virtual world? To realise this project the design program Unity3D as well as Visual Studios 2017 were used. Furthermore, in order to verify that the experience is indeed immersive for the user, an experiment with a sample size of seven people was created. Afterwards the candidates were interviewed via a questionnaire how they felt during the virtual reality application. As a result the study showed that the application has tendencies to be immersive but the users were still aware of the situation. It can be concluded that the immersion was not strong enough to fool users regarding the separation of virtual and real world.
In order to plan the interior of a room, various programs for computers,
smart phones or head-mounted displays are available. The transfer to the
real environment is a difficult task. Therefore an augmented reality approach
is developed to illustrate the planning in the real room. If several
people want to contribute their ideas, conventional systems require to
work on one device together. The aim of this master thesis is to design and
develop a collaborative spatial planning application in augmented reality.
The application is developed in Unity with ARCore and C#.
This bachelor thesis implements a system for camera tracking based on a particle filter. For this purpose, a marker tracking is realized and the camera position is calculated based on the marker position. The marker is to be found with a particle filter and in order to accomplish this possible marker positions are simulated, also called particles, and weighted with Likelyhood-Functions. The focus lies on the evaluation of different Likelihood-Functions of the particle filter. The Likelyhood functions were implemented in CUDA as part of the implementation.
Clubs, such as Scouts, rely on the work of their volunteer members, who have a variety of tasks to accomplish. Often there are sudden changes in their organization teams and offices, whereby planning steps are lost and inexperience in planning occurs. Since the special requirements are not covered by already existing tools, ScOuT, a planning tool for the organization administration, is designed and developed in this work to support clubs with regard to the mentioned problems. The focus was on identifying and using various suitable guidelines and heuristic methods to create a usable interface. The developed product was evaluated empirically by a user survey in terms of usability.
The result of this study shows that already a high degree of the desired goal could be reached by the inclusion of the guidelines and methods. From this it can be concluded that with the help of user-specific concept ideas and the application of suitable guidelines and methods, a suitable basis for a usable application to support clubs can be created.
This thesis deals with the conception and implementation of an action role-playing game using the game engine Unity. Within the context of an evaluation, the game was supposed to be evaluated with regard to the usability of the integrated control modes, the visual conviction of the animations and the user-friendliness of the tools and visualizations provided. In addition, weaknesses and problems in the game were to be identified through open feedback. The results of the evaluation showed that the game is still expandable in terms of usability and user-friendliness, but has left a good impression on the test persons.
The goal of simulations in computergraphics is the simulation of realistic phenomena of materials. Therefore, internal and external acting forces are accumulated in each timestep. From those, new velocities get calculated that ultimately change the positions of geometry or particles. Position Based Dynamics omits thie velocity layer and directly works on the positions. Constraints are a set of rules defining the simulated material. Those rules must not be violated throughout the simulation. If this happens, the violating positions get changed so that the constraints get fullfilled once again. In this work a PBD-framework gets implemented, that allows simulations of solids and fluids. Constraints get solved using GPU implementations of Gauss-Seidel and Gauss-Jakobi solvers. Results are physically plausible simulations that are real-time capable.
Simulation von Schnee
(2019)
Using physics simulations natural phenomena can be replicated
with the computer. The aim is to calculate a physical feature as correclty as
possible in order to draw conclusions for the real world. Fields of Application
are, for example, medicine, industry, but also games or films.
Snow is a very complex natural phenomenon due to its physical structure
and properties. To simulate snow, different material properties have to be
considered.
The most important method that deals with the simulation of snow and its
dynamics is the material point method. It combines the Lagrangian particles
based on continuum mechanics with a Cartesian grid. The grid enables
communication between the snow particles, which are not actually connected.
For calculation of particles data is transferred from these particles to
the grid nodes. There, calculations are carried out with information about
neighboring particles. The results are then transferred back to the original
particles. Using GPGPU techniques, physical simulations can be implemented
on the graphics card. Procedures like the material point method
can be parallelized well with these techniques.
This paper deals with the physical basics of the material point method and
implements them on the graphics card using compute shaders. Then performance
and quality are evaluated.
The development of a game engine is considered a non-trivial problem. [3] The architecture of such simulation software must be able to manage large amounts of simulation objects in real-time while dealing with “crosscutting concerns” [3,p. 36] between subsystems. The use of object oriented paradigms to model simulation objects in class hierarchies has been reported as incompatible with constantly changing demands during game development [2, p. 9], resulting in anti-patterns and eventual, messy refactoring.[13]
Alternative architectures using data oriented paradigms revolving around object composition and aggregation have been proposed as a result. [13, 9, 1, 11]
This thesis describes the development of such an architecture with the explicit goals to be simple, inherently compatible with data oriented design, and to make reasoning about performance characteristics possible. Concepts are formally defined to help analyze the problem and evaluate results. A functional implementation of the architecture is presented together with use cases common to simulation software.
This bachelor thesis investigates the utilization of the Wii Balance Board
in virtual reality applications. For the investigation a snowboard game is
implemented, in which the virtual avatar can be controlled with the pressure
sensors of the Wii Balance Board. The user should be able to move
playfully and intuitively through the virtual environment by balancing his
body. The immersiveness and the influence on motion sickness and cybersickness
will be investigated. In Addition, the Wii Balance Board will be
compared with the Xbox Controller. The aim of the work is to evaluate
whether the Wii Balance Board is able to allow free movement in virtual
environments and whether it is more advantageous to use it rather than
a conventional controller. The results of the survey indicate that the Wii
Balance Board has a positive influence on the immersivness of the game,
despite better game results by using a conventional controller. The survey
also reveals that the use of the Wii Balance Board is responsible for more
motion-sickness/cybersickness cases.
Simulation von Rauch
(2019)
This bachelor thesis deals with the simulation of smoke in a particle
system. Here the possibilities are investigated to implement smoke as
realistically as possible in a particle system and to calculate it in real time.
The physical simulation is based on the work of Müller and
Ren, who deal with the physical properties of fluids and gases.
The simulation was implemented on the GPU using C++, OpenGL and
the compute shaders available in OpenGL. Special attention was paid
to the performance of the simulation. Hoetzlein techniques are
used to accelerate the particle system. Two acceleration methods were
then implemented and compared. The runtime, but also the used memory
space of the GPU is discussed.
The goal of this work is the induction, conception, implementation and evaluation of an interactive game application among Android. The game genre of the app is a 2D-Jump ‘n’ Run Side-Scroller, whose graphical implementation is based on the four elements earth, fire, water and wind. The application should have classic functions of a Jump ‘n’ Run game and allow the player to overcome the four game worlds to find the finish. The implementation is based on Unity Engine and Adobe Photoshop. A user test asks basic questions about the application and specific questions about the research question, which are then evaluated. The research question examines the connection between fun factor and color perception while playing the app. Represented by the natural color combinations of the four elements. At the end possibilities for expansion and future prospects will be discussed.
In this thesis, the theory of video seethrough is fundamentally presented on the basis of a panoramic view from several camera frames of
different perspectives. Based on this, a system was designed and implemented in which video streams are put together into a panoramic image by
perspective distortion. This is then projected onto the inside of a cylinder
with the virtual position of the viewer in the middle. Finally, the resulting
video panoramas will be displayed in VR glasses. Within the implementation some optimizations are also presented, among others those that make
the system real-time capable beyond the task. Furthermore, the developed
system will be evaluated and compared with two other methods.
This bachelor thesis deals with the conception, implementation and evaluation of a Jump'n'Run game and the consideration of the influence of achievment systems on players. In the game Age of Tunes you play Bardur, the beardless bard and have to try to free the cursed magical creatures in the world Harmonica. The emphasis of the thesis was the clean conception and gradual development of the game, appealing graphic quality, integration of opponents, a mini-game and the consideration of effects of an achievment system on players. In a final evaluation the game and the behavior could be evaluated regarding the achievments.
A gonioreflectometer is a device to measure the reflection properties of arbitrary materials. In this work, such an apparatus is being built from easily obtainable parts. Therefore three stepper-motors and 809 light-emitting diodes are controlled by an Arduino microcontroller. RGB-images are captured with an industrial camera which serve as refelction data. Furthermore, a control software with several capture programs and a renderer for displaying the measured materials are implemented. These allow capturing and rendering entire bidirectional reflection distribution functions (BRDFs) by which also complex anisotropic material properties can be represented. Although the quality of the results has some artifacts due to shadows of the camera, these artifacts can be largely removed by using special algorithms like inpainting. In addition, the goniorefelctometer is applied to other use cases. One can perform 3D scans, light field capturing and light staging without altering the construction. The quality of these processes also meet the expectations in a positive way. Thus, the gonioreflectometer built in this work can be seen as a widely applicable and economical alternative to other publications.
This Bachelor thesis describes the conception, implementation and evaluation of a playful augmented reality application for mobile devices. Building on the ARCore SDK, the game pARcours was developed, where the player can place virtual objects in the real environment to build their own parcours. This must be flown through with a likewise virtual aircraft. The main focus in the implementation of the game was on the interaction with the virtual objects and the collision detection of these with real surfaces. Furthermore, various input methods for building the parcours and controlling the aircrafts were examined. In a final evaluation both the game and the various input methods could be evaluated, as well as ARCore with regard to the development of augmented reality applications.
With the appearance of modern virtual reality (VR) headsets on the consumer market, there has been the biggest boom in the history of VR technology. Naturally, this was accompanied by an increasing focus on the problems of current VR hardware. Especially the control in VR has always been a complex topic.
One possible solution is the Leap Motion, a hand tracking device that was initially developed for desktop use, but with the last major software update it can be attached to standard VR headsets. This device allows very precise tracking of the user’s hands and fingers and their replication in the virtual world.
The aim of this work is to design virtual user interfaces that can be operated with the Leap Motion to provide a natural method of interaction between the user and the VR environment. After that, subject tests are performed to evaluate their performance and compare them to traditional VR controllers.
Raytracing von NURBS
(2019)
NURBS sind eine Art von Splines, die besondere Eigenschaften besitzen.
Das ray tracen von NURBS ist eine der Darstellungsmöglichkeiten von NURBS.
Dies ist durch das konkrete berechnen von Schnittpunkten mit Strahlen
möglich. Durch die vielseitige Möglichkeiten der Modellierung mittels NURBS
sind diese beliebt in Anwendungen die im Maschinenbau verwendet werden
und auch anderen CAD-Programmen. Diese Arbeit befasst sich mit der
Berechnung von NURBS-Kurven und -Oberflächen, dem direkten rendern
von diesen und wägt ab ob sich der Aufwand dafür im Vergleich zu Tesselierung
lohnt.
In this master's thesis the principle of hybrid ray tracing, consisting of a rasterization pipeline which includes ray tracing techniques for certain effects, is explained and the implementation of an application which uses a hybrid approach in which ray tracing is used to calculate shadows, ambient occlusion, and reflections and combines those with direct lighting is documented and explained. Hybrid ray tracing is based on the idea of combining the performance and flexibility of rasterization-based approaches with ray tracing to overcome the limitation of not being able to access the complete surrounding geometry at any point in the scene.
While describing the implementation of said application, the RTX API which is being used for ray tracing is explained as well Vulkan, the graphics API used.
Based on the results and the insights gained while using the RTX API, it is assessed in regards of its usage scenarios and technical sophistication.
Deformable Snow Rendering
(2019)
Accurate snow simulation is key to capture snow's iconic visuals. Intricate
methods exist that attempt to grasp snow behaviour in a holistic manner. Computational complexity prevents them from reaching real-time performance. This thesis presents three techniques making use of the GPU that focus on the deformation of a snow surface in real-time. The approaches are examined by their ability to scale with an increasing number of deformation actors and their visual portrayal of snow deformation. The findings indicate that the approaches maintain real-time performance well into several hundred individual deformation actors. However, these approaches each have their individual restrictions handicapping the visual results. An experimental approach is to combine the techniques at reduced deformation actor count to benefit from the detailed, merged deformation pattern.
The aim of this work is to develop a simple concept for monitoring dogs that are alone at home for several hours. The prototypical implementation of such a "DogCam" can be considered as proof of concept. The basis for the prototype‘s implementation are the requirements identified within a conducted requirement analysis. Furthermore, the present work shows which improvements and extensions of the prototypical "DogCam" are possible and which similar projects already exist.
Ist es möglich, allein mittels VR-Headset bei Nutzern Immersion zu
erzeugen? Zur Beantwortung dieser Frage werden zwei Simulationen einer
Achterbahnfahrt ohne haptisches Feedback mittels der Unreal Engine
4.20.3 für ein HTC-Vive VR Headset entwickelt und implementiert. Die
zweite Simulation unterscheidet sich von der ersten durch die Darbietung
außergewöhnlicher Ereignisse während der Fahrt, für die vermutet wird,
dass sie das Immersionserleben verstärken. Elf Probanden nahmen an der
Untersuchung teil. Die Auswertung eines Fragebogens zur Erfassung der
Intensität der Immersion und der Antworten auf offenen Fragen zeigt, dass
Immersion in beiden Simulation erfolgreich erzeugt werden konnte. Manche
Merkmale der Simulation vertieften bei einzelnen Probanden das immersive
Erleben, bei anderen dagegen nicht. Die Bedeutung der Ergebnisse
und Optimierungsmöglichkeiten für künftige Studien werden diskutiert.
The following bachelor thesis gives an overview of various approaches and techniques for procedural generation of three-dimensional city models. Especially the usage of generative grammars is being examined and later used for the implementation of an own application. Its focus was the embedding of predetermined primary street networks as well as the procedural generation of secondary street networks and different kinds of buildings. The application allows the efficient creation of extensive and variably structured city models. However, there are restrictions regarding the realism and variation of the results.
In order to simulate realistic motion sequences, muscles must be able to be modelled anatomically correct. Yet it is only possible in SimPack to define muscles as a straight line between two points. This thesis presents an approach where ellipses can be defined through which a muscle must pass. The main problem is to calculate the length of this muscle through the ellipses. An algorithm is presented that calculates the shortest path of a muscle path through this ellipses. This algorithm is then implemented in Fortran 90 and integrated into an existing muscle model in SimPack.
Im Bereich der Computergraphik bilden die Nicht-Photorealistischen Renderingverfahren einen Schwerpunkt in der technischen und wissenschaftlichen Visualisierung, vor allem aber in den künstlerischen Bereichen. Verschiedene Kunststile, sowie Zeichenmaterialien und ihre Eigenschaften stellen unterschiedliche Herausforderungen dar. Eine dieser Herausforderungen ist hierbei die Simulation flüssiger Zeichenmittel.
Diese Arbeit beschäftigt sich mit der Erstellung eines interaktiven Zeichensystems für ein flüssiges Zeichenmittel, der Aquarellmalerei. Für die Simulation wird eine raue Zeichengrundlage generiert, sowie die Fluid Simulation und das optische Farbverhalten der Aquarellmalerei implementiert.
Global-Illumination is an important part of the rendering of realistic images. However, the computational complexity of an accurate simulation of these effects is too high for the use in real time applications. In this paper Light-Propagation-Volumes, Screen-Space-Reflections and multiple variants of Screen-Space-Ambient-Occlusion are investigated as a solution for real time rendering. It is shown that they are fast enough for the use in real time applications. The various techniques approximate only a few aspects of the light transport, but complement each other.
In no field of computer science has the hardware developed as rapidly as in the field of computer graphics. Today, we can display complex, geometric scenes in real time in immersive systems and also integrate elaborate simulations.
The aim of this work is to realize the simulation of paint splashes in a virtual world. For this purpose, an application will be implemented with the help of Unity, that uses three different techniques to color the environment with the help of paint splashes. Based on this application, the limits and possibilities of the techniques in virtual environments are examined more closely.
This examination shows that an inverse projection produces the best results.
Bildsynthese durch Raytracing gewinnt durch Hardware-Unterstützung in Verbraucher-Grafikkarten eine immer größer werdende Relevanz. Der Linespace dient dabei als eine neue, vielversprechende Beschleunigungsstruktur. Durch seine richtungsbasierte Natur ist es sinnvoll, ihn in andere Datenstrukturen zu integrieren. Bisher wurde er in ein Uniform-Grid integriert. Problematisch werden einheitlich große Voxel allerdings bei Szenen mit variierbarem Detailgrad. Diese Arbeit führt den adaptiven Linespace ein, eine Kombination aus Octree und Linespace. Die Struktur wird hinsichtlich ihrer Beschleunigungsfähigkeit untersucht und mit dem bisherigen Grid-Ansatz verglichen. Es wird gezeigt, dass der adaptive Linespace für hohe Grid-Auflösungen besser skaliert, durch eine ineffiziente GPU-Nutzung allerdings keine optimalen Werte erzielt.
Helicopters are crucial in today’s life. A vast amount of applications prove
their range, which are not coverable by other types of aircraft. But they are
very complex systems, both, technically and physically. This is one of the
reasons why pilot training for helicopters is quite challenging. In the last
two decades flight simulators became a supplementary instrument in the
educational process of pilots. With flight simulators it is possible to replay
uncommon or dangerous situations. In this thesis a simple flight simulator
for helicopters will be developed based on rigid body physics. The foundation is a simplified rotor model which omits complex fluid dynamics. This
helps to keep the implementation simple and illustrative as well as provide simulation rates at real-time. The modules are implemented within
the Unreal Engine in such way, that changing helicopter characteristics is
very easy.
Algorithmische Komposition
(2018)
Algorithmic composition is an interdisciplinary topic that unites music and science. The computer is able to generate algorithmic music with the aid of a specific algorithm. In this bachelor thesis, algorithmic composition is realized with the biology-inspired algorithms called Lindenmayer-system and cellular automaton. In order to realize the compositions, several techniques are presented as well as implemented and evaluated. Those techniques map the generated data from the algorithms on a meaningful musical result.
In no other field of computer science has the hardware been evolved more
quickly than in computer graphics. Therefore the GPU offers, aside from
the pure rendering of triangles, a bunch of further pipeline steps that allows
visualisation of other graphics objects, like freeform surfaces.
This bachelor’s thesis is about the rendering of freeform surfaces, in particular
bezier surfaces. For that reason an implementation for management
and visualisation of bézier surfaces was created for the rendering framework
of the university Koblenz (CVK). For this purpose first a triangulation
was implemented and finally a tesselation of bezier surfaces with normals
and texture coordinates, as well as the handling of trim curves.
In der Computergrafik stellte das echtzeitfähige
Rendern von Haaren und Fell ein Problem dar. Die
Berechnung der Beleuchtung, Schattierung und
Transparenz erfordert einen hohen Rechenaufwand,
welcher sich negativ auf die Performanz auswirkt.
Doch durch verbesserte Hardware und neue Verfahren
ist es möglich, solch komplexe Effekte in Echtzeit
zu simulieren. In folgender Arbeit werden die
Grundlagen des Renderings von Haaren erläutert.
Außerdem wurde im Rahmen der Arbeit eine
echtzeitfähige Demo implementiert, deren zugrunde
liegende Verfahren und Funktionalitäten beschrieben
werden. Um die Demo zu evaluieren wurde die mögliche
Anzahl an Bildern pro Sekunde bei Modellen
unterschiedlicher Komplexität gemessen. Schließlich
wurden die Ergebnisse mit Bildern von echten Haaren
verglichen.
In this bachelor thesis a code for astrophysical self-gravitating fluid
simulation is developed. The code runs mainly on the GPU. Minimal
simplifications of the physical model and some parameters for accuracy
and tuning allow simulations to be performed at interactive framerates
on most modern consumer grade computers that feature a dedicated
graphics card. It is used to simulate the birth of stars from a turbulent
molecular cloud. Multiple features of star formation, like accretion
discs and fragmentation, can be observed in the simulation, even when
low particle counts are used.
In this bachelor thesis a system for the simulation of the movements of molecules is developed. The calculation of the forces between chemically bonded atoms as well as intermolecular forces is done almost entirely on the GPU. The visualization of the simulation happens at an interactive framerate. To achieve rendering in realtime on off-the-shelf graphics cards, apt optimizations and slight abstractions of the underlying physical models are needed. One can control the execution speed or completely stop the simulation at any given moment. Some of the parameters of the underlying physical models of the simulation can be modified at runtime. With the right settings for the parameters, some phenomena of molecular dynamics can be observed, for example the spacial structure of the molecules.
The following work describes the prototypical conception and development of the stat-raising game "Adventurer's Guild" using the game engine Ren'Py. The game's narrative is influenced by player decisions and the planning of activities. The game is to be visually pleasing and enjoyable.
After giving an overview of stat-raising as a genre, the existing games "Dandelion - Wishes Brought to You", "Pastry Lovers", "Long Live the Queen" and "Magical Diary" are analysed to pinpoint various strengths and weaknesses of their different takes on the genre.
The resultant findings are used for the conception of a new stat-raising game.
The game mechanics and the design decisions made are then shown in screenshots and thoroughly explained.
In a final assessment, the game will be examined with regard to the given task. Further possibilities for potential improvements and expansions will be detailed at the end.
Photo realistic rendering of fur is a common problem in computer graphics and is often needed in animation films. This work presents two illumination models, originally presented for human hair rendering. The first model is from Marschner et al. presented in 2003, which is the basis of many other models. The second model is from d’Eon et al., which was presented in 2011. Both models are implemented into a path tracer, which simulates global illumination. The special features of fur fibers in contrast to human hair fibers will be shown and an explanation, to why both models can also be used for fur rendering, will be given. The main point of interest is a realistic visualization of fur. In addition to that the performance of both models will be compared and a suggestion to improve the performance will be given and evaluated in form of the use of a cylindrical intersection object for path tracing.
Volumetrische Beleuchtung
(2018)
Volumetric lighting is a common lighting phenomena in nature and carries an important role in the realistic appearance of computergenerated images. This thesis explains the physical background of this phenomena and lists common modells for visualising volumetric lighting in Computergraphics. Following this, this thesis compares three methods for visualising volumetric lighting with modern graphics hardware and compares these according to their abilities, restrictions and performance in an OpenGL implementation.
The present thesis gives an overview of the general conditions for the programming of graphics cards. For this purpose, the most important Application Programming Interfaces (APIs) available on the market are presented and compared. Subsequently, two standard algorithms from the field data processing, prefix sum and radixsort are presented and examined with regard to the implementation with parallel programming on the GPU. Both algorithms were implemented using the OpenGL-API and OpenGL compute shaders. Finally, the execution times of the two algorithms were compared.
The present thesis describes the development of an OpenGL-based tool visualizing cavities of proteins, which can be observed during a static docking simulation. The goal is to achieve knowledge about interactions between proteins and ligands based on information about distances between them. At first chemical basics, which motivate the topic and are important for understanding the topic and the used algorithms, are presented. Furthermore existing software, which deals with similar issues, is described. Next the prerequisites for the development of the program are presented and the tool is described in detail. Concluding the tool is evaluated concerning performance and usage and a summarizing conclusion is given. The program turns out as a helpful tool for current research and a good base for further and deeper research projects.
This Bachelor thesis illustrates the connection between the technologies Augmented and Virtual Reality and creates an expedient interdependency of the two forms of presentation. For this purpose, an application in the area of interior design has been implemented, where designing a room can be made more intuitive by using Augmented Reality, as it provides a realistic impression of the planned apartment with a Virtual Reality simulation. Based on the relevant knowledge, a project-concept has been drafted and realized by using several development systems. During a series of tests this implementation has been evaluated and subsequently optimized. The result confirms the assumption, that Augmented and Virtual Reality with their strengths can be combined to an evident solution. This thesis is relevant for computer science students as well as for people interested in innovative solutions.
In dieser Arbeit wird ein System zur Erzeugung und Darstellung stereoskopischen Video-Panoramen vorgestellt. Neben der theoretischen Grundlagen werden der Aufbau und die Funktionsweise dieses Systems erläutert.
Dazu werden spezielle Kameras verwendet, die Panoramen aufnehmen
können und zur Wiedergabe synchronisiert werden. Anschließend wird ein Renderer implementiert, welcher die Panoramen mithilfe einer VirtualReality Brille stereoskopisch darstellen kann. Dafür werden separate Aufnahmen für die beiden Augen gemacht und getrennt wiedergegeben. Zum Abschluss wird das entstandene Video-Panorama mit einem Panorama eines schon bestehenden Systems verglichen.
How does gameplay influence the fun in video games? This article will search for an answer to this question by using a self-made video game created from scratch. This video game will be programmed in two versions with differences only in gameplay. Several test persons are then to play this game. A survey will be answered afterwards. In order to gain values that are merely influenced by gameplay changes, thoughts on the game design and conception were made. Results suggest that gameplay has a big impact on fun in video games. But gameplay isn't the only responsible factor that makes a video game amusing. Psychological aspects are present when the gameplay of a video game changes.
Es wird ein Augmented-Reality Ansatz zur Erforschung modularer OSGi-Softwaresysteme präsentiert. Der Prototyp wird unter der Verwendung der Microsoft HoloLens implementiert. Module, wie Komponenten und Packages, werden in einer virtuellen Stadt dargestellt. Dieser Ansatz ermöglicht es dem Anwender, die Software-Architektur mittels intuitiver Navigation zu erkunden: Spracheingabe, Blickpunkt- und Gestenkontrolle. Eine multifunktionale Benutzeroberfläche wird vorgestellt, die für verschiedene Zielgruppen adaptiert werden kann. Viele veröffentlichte Visualisierungen weisen keine klare Zielgruppendefinition auf. Das Konzept kann leicht auf andere Darstellungsformen, wie beispielsweise der Inselmetapher übertragen werden. Erste Ergebnisse einer Evaluierung, die mittels kleiner strukturierter Interviews gewonnen werden konnten, werden präsentiert. Die Probanden mussten vier Programm-verständnis Aufgaben lösen und ihren Aufwand, sowie ihre Arbeitsbelastung einschätzen. Die Ergebnisse bilden eine gute Grundlage für weitere Forschung im Bereich der Software- Visualisierung in Augmented Reality.
Das Ziel der vorliegenden Masterarbeit ist es, einen Einführungskurs in die Computervisualistik mit dem Schwerpunkt Computergrafik zu konzeptionieren und zu prototypisieren. Der Kurs sollte Grundlagen der Computergrafik vermitteln und dabei Bezüge zu anderen Veranstaltungen des Studiums herstellen, um Motivation und Verständnis für die komplexen Zusammenhänge der Studieninhalte in der Computervisualistik zu schaffen. Der aktuelle Studiengangplan weist hier bislang ein erkennbares Defizit auf. Für den Einführungskurs wurden prototypische Lerneinheiten auf Grundlage der didaktischen Methode der Moderation und unter Verwendung von Unity entwickelt. Konzept und Prototypen wurden an Probanden ohne informationstechnischen Hintergrund evaluiert. Die Ergebnisse zeigten, dass Unity eine geeignete Oberfläche für die Vermittlung der Informationen bietet. Diese stieß auf Akzeptanz und konnte leichte Zugänglichkeit bei den Probanden aufweisen, obwohl die Lerneinheiten selbst kleinere Schwächen aufwiesen. Im Anschluss an die erste Evaluationsphase wurde eine qualitative Umfrage mit Alumini der Computervisualistik durchgeführt. Die Ergebnisse bestätigten den Bedarf nach einer einführenden Veranstaltung zur Orientierung und zur Förderung von Motivation und Verständnis für die breiten Themengebiete der Computervisualistik.
E-Learning Anwendungen sind heutzutage im Trend. Jedoch nicht nur aus diesem Grund sind sie vom großen Interesse. Im Vordergrund steht ihr didaktisches Konzept. Heutzutage ist es technisch möglich, die Teilnehmer interaktiv in einen
E- Learning Kurs einzubinden. Die Lernschritte können durch die Anwendung kontrolliert werden. Im Gegensatz zu einer Vorlesung, kann die Theorie direkt mit der Praxis verknüpft werden. Das Ziel der Arbeit ist die Erstellung eines Konzeptes und die Entwicklung eines Prototypen einer interaktiven Entwicklungsumgebung von Java für Programmieranfänger. In dieser Arbeit wurden aktuelle E-Learning Plattformen zu Java analysiert. Aus den gewonnen Erkenntnissen wurde ein Konzept für eine E-Learningplattform entwickelt. Dieses Konzept wurde erfolgreich als Prototyp implementiert. Für die Implementation wurden bewährte Technologien, wie das Django-Framework und das Javascript-Framework Vue.js eingesetzt. Der Kurs wurde von neun Teilnehmern getestet. Zusätzlich wurde eine Umfrage zu der Kursanwendung durchgeführt. Das Testergebnis bestätigt, dass die Teilnehmer den Kurs bestanden haben.
Augmented reality is being present for many years. Through progress in technology smaller augmented reality glasses became possible. These new technologies allow many new ways of interaction and usage of augmented reality.
This thesis is about the Microsoft HoloLens and its possiblities for consumers and industry. In the context of this thesis a new interactive and augmented application to measure the possiblities and limitations of the Microsoft HoloLens has been developed. The scene is an assembly szenario with a step by step instruction of building with Lego bricks. The evaluation showed that the HoloLens can already be used to assist in assembling scenarios and offers some advantages over other methods, although the glasses still have some flaws.
This thesis presents two methods for the computation of global illumination. The first is an extension of Reflective Shadow Maps with an additional shadow test in order to handle occlusion. The second method is a novel, bidirectional Light-Injection approach. Rays originating from the light source are traced through the scene and stored inside the shafts of the Linespace datastructure. These shafts are a discretization of the possible spatial directions. The Linespaces are embedded in a Uniform Grid. When retrieving this pre-calculated lightning information no traversal of datastructures and no additional indirection is necessary in the best-case scenario. This reduces computation time and variance compared to Pathtracing. Areas that are mostly lit indirectly and glas profit the most from this. However, the result is only approximative in nature and produces visible artifacts.
This thesis tests several methods and measures in pathtracing for selecting either the Line Space or the Bounding Volume Hierarchy data structure to make use of the advantages of both. The structures are defined locally around each object and each Line Space shaft contains one candidate ID each. All implementation is done as a C++ and OpenGL framework with compute shaders handling the pathtracing and Line Space generation. The measures include the probability distribution, the effect dependency, as well as a distance threshold and are tested against several different scenes. In most situations, the results show a noticeable increase in performance, partly only with minor visual differences, with the probability measure producing the highest quality images for a given performance. The fundamental problems of the Line Space concering the high memory consumption and a long generation time compared to the BVH still persist, despite the object local structure, a minimal amount of data per shaft and the compute shader implementation.
In scientific data visualization huge amounts of data are generated, which implies the task of analyzing these in an efficient way. This includes the reliable detection of important parts and a low expenditure of time and effort. This is especially important for the big-sized seismic volume datasets, that are required for the exploration of oil and gas deposits. Since the generated data is complex and a manual analysis is very time-intensive, a semi-automatic approach could on one hand reduce the time required for the analysis and on the other hand offer more flexibility, than a fully automatic approach.
This master's thesis introduces an algorithm, which is capable of locating regions of interest in seismic volume data automatically by detecting anomalies in local histograms. Furthermore the results are visualized and a variety of tools for the exploration and interpretation of the detected regions are developed. The approach is evaluated by experiments with synthetic data and in interviews with domain experts on the basis of real-world data. Conclusively further improvements to integrate the algorithm into the seismic interpretation workflow are suggested.
With the emergence of current generation head-mounted displays (HMDs), virtual reality (VR) is regaining much interest in the field of medical imaging and diagnosis. Room-scale exploration of CT or MRI data in virtual reality feels like an intuitive application. However in VR retaining a high frame rate is more critical than for conventional user interaction seated in front of a screen. There is strong scientific evidence suggesting that low frame rates and high latency have a strong influence on the appearance of cybersickness. This thesis explores two practical approaches to overcome the high computational cost of volume rendering for virtual reality. One lies within the exploitation of coherency properties of the especially costly stereoscopic rendering setup. The main contribution is the development and evaluation of a novel acceleration technique for stereoscopic GPU ray casting. Additionally, an asynchronous rendering approach is pursued to minimize the amount of latency in the system. A selection of image warping techniques has been implemented and evaluated methodically, assessing the applicability for VR volume rendering.
One of the greatest goals in computer graphics is the aesthetic representation of objects. In addition to conventional methods, another field focuses on non-photorealistic renderings. The so-called example-based rendering is an area where users can transfer their art style to a pre-computed 3D rendering, using a hand-painted template. There are some algorithms that already provide impressive results, but their problem is that most of these procedures count as offline methods and are not able to produce results in real-time. For this reason, this work show a method that satisfies this condition. In addition, the influence of the run-time reduction on the results is investigated. Requirements are defined, to which the method and its results are examined. Other methods in this field are referenced and compared with their results.
This thesis presents a novel technique in computer graphics to simulate realtime
global illumination using path tracing. Path tracing is done with compute shaders on the graphics card (GPU) to perform rendering in a highly parallelized manner. To improve the overall performance of tracing rays, the Line Space is used as an acceleration data structure in different variations, resulting in better
empty space skipping. The Line Space saves scene information based on a previous voxelization in direction-dependent shafts and is generated and traversed on the GPU. With this procedure, indirect lighting and soft shadows can be computed in a physically correct way. Furthermore, using the Line Space, path tracing can be performed mostly independent of the complexity of the scene geometry with over 100 frames per second, which is truly real-time and much faster than using a comparable voxel grid. The image quality is not affected negatively by this technique and the shadow quality is in most cases much better compared to shadow-mapping.
The market for virtual reality is rapidly evolving regarding its hardware components. Further applications are the result of this progress. In addition to the gaming market virtual reality offers further possibilities and advantages in research. That way this technology provides the investigation of perceptual phenomena. Therefore the present thesis aimed to examine the induced roelofs effect in a virtual environment and in reality in front of a computer screen. The roelofs effect describes a misperception that occurs if a persons midline and a target surrounding frame are offset, which results in a false localisation of the object. Thus the present study provides insight into the influence of a computer screen regarding this effect. Moreover, conclusions concerning the suitability of virtual reality in perceptual research are drawn. The results obtained by the virtual reality indicated a greater degree of perceptual distortion. Therefore the fixed frame of the computer screen can be assumed as an additional orientation.
This thesis deals with the exploration of different interaction possibilities
for three-dimensional, virtual objects in a real environment. The focus lies
especially on interaction possibilities from new AR-technologies.
A playful prototype of an application for Microsofts HoloLens will be
designed and implemented. The prototype consists of three parts. The first
part is the scan-process of the real environment of the user. In the second
part the user can augment the real environment with three-dimensional,
virtual objects. In the third part the user is supposed to navigate a virtual
avatar through the real environment.
The interaction possibilities of the HoloLens like Gaze, Gesture and VoiceInput
will be evaluated in the following categories menu navigation, positioning
of three-dimensional objects in a real environment and controlling an
avatar.
Motion capture refers to the process of capturing, processing and trans- lating real motions onto a 3D model. Not only in the movie and gaming industries, motion capture creates an indispensable realism of human and animal movement. Also in the context of robotics, medical movement therapy, as well as in AR and VR, motion capture is used extensively. In addition to the well established optical processes, especially in the last three areas, alternative systems based on inertial navigation (IMUs) are being used in-creasingly, because they do not rely on external cameras and thus limit the area of movement considerably less.
Fast evolving technical progress in the manufacturing of such IMUs allows building small sensors, wearable on the body which can transfer movements to a computer. The development of applying inertial systems to a motion capture context, however, is still at an early state. Problems like drift can currently only be minimized by adding additional hardware for correcting the read data.
In the following master thesis an IMU based motion capture system is designed and constructed. This contains the assembly of the hardware components as well as processing of the received movement data on the software side and their application to a 3D model.
This thesis explores different approaches for the acceleration of raytracing calculations on the graphics processing unit (GPU). For that a voxel grid is used and extended by the linespace data structure. The linespace consists of direction based shafts and stores the objects located in those shafts in a candidate list. Different methods for the sorting and traversal of the linespace are presented and evaluated. The shown methods cannot provide a speed up of the frame rate without resulting in a loss of image quality.
This thesis presents the use of a local linespace data structure, which is designed and implemented on the basis of an existing GPU-based raytra- cer with a global linespace data structure. For each scene object, an N-tree is generated whose nodes each have a linespace. This saves informations about existing geometry in its shafts. A shaft represents a volume between two faces on the outside of the node. This allows a faster skipping of em- pty spaces during raytracing. Identical objects can access already calcula- ted linespaces, which can reduce the memory requirement by up to 94.13% and the initialization time of the datastructure by up to 97.15%. Due to the local access possibilities dynamic scenes can be visualized. An increase in quality can also be observed.
This bachelor thesis deals with the development of an application for the Microsoft HoloLens. The application is used for the marketing of advertis- ing spaces that belongs to the company awk AUSSENWERBUNG GmbH. On basis of the development, the question is answered which are the pos- sibilities and limitations of the HoloLens and the Mixed Reality Platform. Problems are also addressed, that come along with the development of an application for such a new technology, like the HoloLens is. Beside the new technologies, some challenges come also from the applications oper- ational locations. Several application examples and presentations suggest, that the HoloLens is primarily designed for indoor usage. Instead the de- veloped application is for outdoor use only. During the development, sev- eral insights can be gained about this new technology. On the one hand it becomes clear, that the HoloLens and also the development environment aren’t completely matured yet. On the other hand, that the HoloLens isn’t an outdoor device at all. Despite the difficulties during the development, there occur many possibilities that are associated with this new technology.
Im Bereich Augmented Reality ist es von großer Bedeutung, dass virtuelle
Objekte möglichst realistisch in ein Kamerabild eingebettet werden. Nur
so ist es möglich, dem Nutzer eine immersive Erfahrung zu bieten. Dazu
gehört unter anderem, Verdeckung dieser Objekte korrekt zu behandeln.
Während schon verschiedene Ansätze existieren, dieses Verdeckungsproblem
zu beheben, wird in dieser Arbeit eine Lösung mittels Natural Image
Matting vorgestellt. Mit Hilfe einer Tiefenkamera wird das Kamerabild in
Vorder- und Hintergrund aufgeteilt und anschließend das virtuelle Objekt
im Bild platziert. Für Bereiche, in denen die Zugehörigkeit zu Vorder- oder
Hintergrund nicht eindeutig ist, wird anhand bekannter Pixel ein Transparenz-
Wert geschätzt. Es werden Methoden präsentiert, welche einen
Ablauf des Image Matting in Echtzeit ermöglichen. Zudem werden
Verbesserungsmöglichkeiten dieser Methoden präsentiert und gezeigt, dass
durch diese eine höhere Bildqualität für schwierige Szenen erreicht wird.
Statistical Shape Models (SSMs) are one of the most successful tools in 3Dimage analysis and especially medical image segmentation. By modeling the variability of a population of training shapes, the statistical information inherent in such data are used for automatic interpretation of new images. However, building a high-quality SSM requires manually generated ground truth data from clinical experts. Unfortunately, the acquisition of such data is a time-consuming, error-prone and subjective process. Due to this effort, the majority of SSMs is often based on a limited set of this ground truth training data, which makes the models less statistically meaningful. On the other hand, image data itself is abundant in clinics from daily routine. In this work, methods for automatically constructing a reliable SSM without the need of manual image interpretation from experts are proposed. Thus, the training data is assumed to be the result of any segmentation algorithm or may originate from other sources, e.g. non-expert manual delineations. Depending on the algorithm, the output segmentations will contain errors to a higher or lower degree. In order to account for these errors, areas of low probability of being a boundary should be excluded from the training of the SSM. Therefore, the probabilities are estimated with the help of image-based approaches. By including many shape variations, the corrupted parts can be statistically reconstructed. Two approaches for reconstruction are proposed - an Imputation method and Weighted Robust Principal Component Analysis (WRPCA). This allows the inclusion of many data sets from clinical routine, covering a lot more variations of shape examples. To assess the quality of the models, which are robust against erroneous training shapes, an evaluation compares the generalization and specificity ability to a model build from ground truth data. The results show, that especially WRPCA is a powerful tool to handle corrupted parts and yields to reasonable models, which have a higher quality than the initial segmentations.
This thesis presents an approach to optimizing the computation of soft shadows from area lights. The light source is sampled uniformly by traversing shadow rays as packets through an N-tree. This data structure stores an additional line space for every node. A line space stores precomputed information about geometry inside of shafts from one to another side of the node. This visibility information is used to terminate a ray. Additionally the graphics processing unit (short GPU) is used to speed up the computations through parallelism. The scene is rendered with OpenGL and the shadow value is computed on the GPU for each pixel. Evaluating the implementation shows a performance gain of 86% by comparison to the CPU, if using the GPU implementation. Using the line space instead of triangle intersections also increases the performance. The implementation provides good scaling with an increasing amount of triangles and has no visual disadvantages for many rays.
Augmented Reality has many areas of application. It can be used to simplify everyday life as well as working processes. However, since there are
many manufacturers that offer greatly varying systems, choosing the correct system according to application as well as cross-platform development are dfficult. This thesis attempts to develop an application which can be used to simulate Augmented Reality devices on Virtual Reality systems. This should simplify the processes of choosing a system as well as cross-platform
development.
Since the simulation will be designed to run on mobile devices, it should be possible to render high quality, realistic environments in advance, using a panoramic image. On a Virtual Reality device, they need to be displayed as a stereoscopic image. To achieve this, several methods are presented that can be used to perform this conversion. An editor will be created which will allow the creation of scenes, configuration of Augmented Reality devices and displaying them on a Virtual Reality system. For closing this thesis a test will be performed, to check the quality of the simulation as well as improvements that can be made.
A special challenge of the basic musical education of children is to give them an understanding of reading and writing musical scores. During the training of young choristers it is furthermore important to educate them in directly transforming the written scores into sounds.
Therefore it is an interesting idea to play the sounds to the children via piano or keyboard and simultaneously present them on a screen in musical notation.
The aim of this bachelor thesis is the implementation of such a system that allows to enter scores using a MIDI-compatible keyboard and then depicting these as musical notation. The prototype of the application operates in three steps. It receives the musical scores via keyboard in form of MIDIdatasets. These MIDI-information are converted to the MusicXML-format. Based on this MusicXML-notation the software finally generates and displays the visual output.
The goal of this thesis is to create and develop a concept for a mobile city guide combined with game-based contents.
The application is intented to support flexible and independent exploration of the city of Koblenz.
Based on the geographical data, historical information for and interesting stories of various places were provided in this application. These informations are combined with playful elements in order to create a motivating concept.
Therefore, related approaches were examined and, combined with own ideas, a new concept has been developed. This concept has been prototypically implemented as an Android application and afterwards evaluated by 15 test persons. A questionnaire was used to examine the operability, the motivation of game patterns and the additional value of the application.
In einer Welt, in der mittlerweile "Die Cloud" als Lösung für nahezu alles angepriesen wird, stellt sich immer häufiger die Frage, ob man seine persönlichen Daten einem Fremden anvertrauen möchte, oder sie doch lieber unter der eigenen Kontrolle behält. Für die Befürworter der letzten Option steht "ownCloud" als freies Softwarepaket zur Verfügung, um eine eigene Cloud aufzusetzen und ihre Inhalte mit Anderen zu teilen.
Um das Teilen von Lernwerkzeugen zu vereinheitlichen und damit zu vereinfachen, wurde von IMS GLOBAL die "Learning Tools Interoperability" Spezifikation - kurz LTI - entwickelt. Diese wird inzwischen von einer zunehmenden Anzahl von Lernmanagementsystemen und Lernressourcen unterstützt. Eine interessante Herausforderung ist daher, zu untersuchen, ob und wie man ownCloud mit verschiedenen bestehenden Lernwerkzeugen mittels LTI verbinden und daraus Nutzen ziehen kann.
Ziel dieser Arbeit ist es, ein Plugin für ownCloud zu konzeptionieren und zu entwickeln, das die Kommunikation mit Lernwerkzeugen per LTI
ermöglicht. Dabei soll sowohl die Consumer- als auch die Providerseite mit einem Proof of Concept berücksichtigt werden, um jeweils die Möglichkeiten und Grenzen dieser Verbindungen zu untersuchen.
Der natürliche Prozess der Verwitterung ist ein komplexer Vorgang, der von unterschiedlichsten Parametern beeinflusstwird. Hauptbestandteil dieses Prozesses ist das Zusammenziehen des Fruchtvolumens infolge von Wasserverlust durch Transpiration sowie die Veränderung der Fruchtfarbe und Oberfläche. Es wurden bereits Verfahren entwickelt, die diese Eigenschaften mit Hilfe von Parametrisierung sowie physikalischer Ansätze simulieren. Die in dieser Arbeit erstellte Anwendung simuliert das Fruchtfleisch durch ein Tetraedernetz und die Veränderung der Haut mit Hilfe von dynamischer Texturanpassung. Der entwickelte Algorithmus arbeitet in linearer Laufzeit und seine Ergebnisse werden anhand selbst erstellter Fruchtmodelle präsentiert.
Ray Tracing als Bildsyntheseverfahren ist relevant für viele Anwendungsbereiche, da es Aspekte des Lichttransports physikalisch korrekt simulieren kann. Aufgrund des hohen Berechnungsaufwands sind der Einsatz von Datenstrukturen zur Beschleunigung und die parallele Verarbeitung notwendig. GPUs sind inzwischen hoch parallele, programmierbare Prozessoren mit zahlreichen Kernen und eignen sich aufgrund ihrer hohen Leistungsfähigkeit dazu, aufwändige, parallelisierbare Probleme zu lösen. In dieser Arbeit geht es um GPU Ray Tracing, beschleunigt durch Bounding Volume Hierarchien (BVH). Auf Basis relevanter Veröffentlichungen zu Aufbau und Traversierung von BVHs und der Abbildung des Ray Tracing Prozesses auf die GPU Architektur wird ein GPU Ray Tracer konzeptioniert und entwickelt. Während der BVH Aufbau vorab auf dem Host stattfindet, wird der gesamte Ray Tracing Prozess durch mehrere Kernel komplett auf der GPU ausgeführt. Die Implementierung der Kernel erfolgt in Form von OpenGL Compute Shader Programmen, und die Aufteilung des Ray Tracers auf mehrere Kernel ist durch die GPU Achitektur und das SIMT Ausführungsmodell motiviert. Für die Speicherorganisation der binären BVHs werden zwei Varianten betrachtet, klassisch und als MBVH, wobei sich die MBVH Organisation als effizienter erweist. Zudem werden verschiedene Varianten für die Traversierung ohne Stack und für die Stack-basierte Traversierung umgesetzt und bewertet. Der in mehrere Kernel strukturierte GPU Ray Tracer wird zudem mit einer Einzelkernel Version verglichen. Die besten Ergebnisse erreicht die Traversierung ohne Stack mit einem while-while Ablauf und MBVH im Rahmen des aufgeteilten GPU Ray Tracers.
One of the fundamental decisions during the development of any system is the representation of data. In computer graphics, objects are usually represented as sets of triangles. There are however many different variants with their own strengths and weaknesses. This thesis will explore distancefields as a representation for objects. Distancefields are functions, which map every point in space to the distance to the closest surface point. While this description is very simple, a number of interesting properties can be derived, allowing for a multitude of shapes, operations and effects. An overview of the necessary background and methods is given. Furthermore, some extended or new approaches are presented, such as displaying implicit surfaces, approximating indirect illumination or implementing a GPU tracer.
While Virtual Reality has been around for decades it gained new life in recent years. The release of the first consumer hardware devices allows fully immersive and affordable VR for the user at home. This availability lead to a new focus of research on technical problems as well as psychological effects. The concepts of presence, describing the feeling of being in the virtual place, body ownership and their impact are central topics in research for a long time and still not fully understood.
To enable further research in the area of Mixed Reality, we want to introduce a framework that integrates the users body and surroundings inside a visual coherent virtual environment. As one of two main aspects we want to merge real and virtual objects to a shared environment in a way such that they are no longer visually distinguishable. To achieve this the main focus is not supposed to be on a high graphical fidelity but on a simplified representation of reality. The essential question is, what level of visual realism is necessary to create a believable mixed reality environment that induces a sense of presence in the user? The second aspect considers the integration of virtual persons. Can characters be recorded and replayed in a way such that they are perceived as believable entities of the world and therefore act as a part of the users environment?
The purpose of this thesis was the development of a framework called Mixed Reality Embodiment Platform. This inital system implements fundamental functionalities to be used as a basis for future extensions to the framework. We also provide a first application that enables user studies to evaluate the framework and contribute to aforementioned research questions.
This thesis presents the analysis of gamebased touristic applications. In tourism, actions can only be motivated intrinsic. Thus, this thesis at first researches specific intrinsic motivation concepts. It shows how gamebased motivation can be produced on purpose and answers the question whether gamebased motivation can be transferred to non-gamebased applications.
Using these results, different touristic applications have been developed and evaluated.
All applications aimed to add value to the touristic experience. The applications are sorted by their mobility. There are completely mobile, completely stationary and hybrid systems in this work. There are different ways to add value which are presented in this work: Gamebased exploration, knowledge transfer and social interaction between tourists.
Finally, an authoring tool for gamebased touristic tours on smartphones is presented.
In recent years head mounted displays (HMD) and their abilities to create virtual realities comparable with the real world moved more into the focus of press coverage and consumers. The reason for this lies in constant improvements in available computing power, miniaturisation of components as well as the constantly shrinking power consumption. These trends originate in the general technical progress driven by advancements made in smartphone sector. This gives more people than ever access to the required components to create these virtual realities. However at the same time there is only limited research which uses the current generation of HMDs especially when comparing the virtual and real world against each other. The approach of this thesis is to look into the process of navigating both real and virtual spaces while using modern hardware and software. One of the key areas are the spatial and peripheral perception without which it would be difficult to navigate a given space. The influence of prior real and virtual experiences on these will be another key aspect. The final area of focus is the influence on the emotional state and how it compares to the real world. To research these influences a experiment using the Oculus Rift DK2 HMD will be held in which subjects will be guided through a real space as well as a virtual model of it. Data will be gather in a quantitative manner by using surveys. Finally, the findings will be discussed based on a statistical evaluation. During these tests the different perception of distances and room size will the compared and how they change based on the current reality. Furthermore, the influence of prior spatial activities both in the real and the virtual world will looked into. Lastly, it will be checked how real these virtual worlds are and if they are sufficiently sophisticated to trigger the same emotional responses as the real world.
This work covers techniques for interactive and physically - based rendering of hair for computer generated imagery (CGI). To this end techniques
for the simulation and approximation of the interaction of light with hair are derived and presented. Furthermore it is described how hair, despite such computationally expensive algorithms, can be rendered interactively.
Techniques for computing the shadowing in hair as well as approaches to render hair as transparent geometry are also presented. A main focus of
this work is the DBK-Buffer, which was conceived, implemented and evaluated. Using the DBK-Buffer, it is possible to render thousands of hairs as
transparent geometry without being dependent on either the newest GPU hardware generation or a great amount of video memory. Moreover, a comprehensive evaluation of all the techniques described was conducted with respect to the visual quality, performance and memory requirements. This
revealed that hair can be rendered physically - based at interactive or even at real - time frame rates.
This thesis shows an interaction of primitives in a three-dimensional space which is done by gestures. Functions which are difficult to do by gestures without any absolute feeling of the position are implemented with a touchscreen. Besides the touchscreen a second input device, a Leap-Motion, is used to obtain data of the motion of the hand. To get its data the Leap-Motion uses two CCD-cameras and three infrared LEDs. The interactions that can be done without any feedback of the absolute position are the translation, rotation and scale. These three and the movement through space are implemented as gestures in this thesis. This is done in Blender with the BlenderrnGame Engine and Python. The only function which has been implemented for the touchscreen is to select an object. Later on, a comparative control of the mouse was invented to contrast it with the control of the gestures. There are two big differences between these two controls. On the one hand, the gesture controls can be done in a three-dimensional space but most people aren't used to it yet. On the other hand, there is just a two-dimensional input possibility with the mouse control. Otherwise it is familiar to most persons. The evaluation should reveal if people prefer interaction by mouse control or by gestures. The result shows that the prefered control is done by the mouse. However in some categories of the tests the gestures are quite close to the result of the mouse.
Real-time graphics applications are tending to get more realistic and approximate real world illumination gets more reasonable due to improvement of graphics hardware. Using a wide variation of algorithms and ideas, graphics processing units (GPU) can simulate complex lighting situations rendering computer generated imagery with complicated effects such as shadows, refraction and reflection of light. Particularly, reflections are an improvement of realism, because they make shiny materials, e.g. brushed metals, wet surfaces like puddles or polished floors, appear more realistic and reveal information of their properties such as roughness and reflectance. Moreover, reflections can get more complex, depending on the view: a wet surface like a street during rain for example will reflect lights depending on the distance of the viewer, resulting in more streaky reflection, which will look more stretched, if the viewer is locatedrnfarther away from the light source. This bachelor thesis aims to give an overview of the state-of-the-art in terms of rendering reflections. Understanding light is a basic need to understand reflections and therefore a physical model of light and its reflection will be covered in section 2, followed by the motivational section 2.2, that will give visual appealing examples for reflections from the real world and the media. Coming to rendering techniques, first, the main principle will be explained in section 3 followed by a short general view of a wide variety of approaches that try to generate correct reflections in section 4. This thesis will describe the implementation of three major algorithms, that produce plausible local reflections. Therefore, the developed framework is described in section 5, then three major algorithms will be covered, that are common methods in most current game and graphics engines: Screen space reflections (SSR), parallax-corrected cube mapping (PCCM) and billboard reflections (BBR). After describing their functional principle, they will be analysed of their visual quality and the possibilities of their real-time application. Finally they will be compared to each other to investigate the advantages and disadvantages over each other. In conclusion, the gained experiences will be described by summarizing advantages and disadvantages of each technique and giving suggestions for improvements. A short perspective will be given, trying to create a view of upcoming real-time rendering techniques for the creation of reflections as specular effects.
In this thesis, we deal with the question if challenge, flow and fun in computer games are related to each other, and which influence the motivational, psychological components motivation of success, motivation of failure and the chance of success do have. In addition, we want to know if a free choice in the level of difficulty is the optimal way to flow. To examine these theories, a study based on an online survey was executed, in which the participants played the game “flOw“. The results were evaluated with the help of a two-factorial analysis of variance with repeated measurement and tests on correlation. Thereby we found out that there actually exists a relation between challenge, flow and fun and that motivation does matter indirectly.
In this thesis, an interactive application is developed for Android OS. The application is about a virtual-reality game. The game is settled in the genre of first-person shooters and takes place in a space scenario. By using a stereo renderer, it is possible to play the game combined with virtual-reality glasses.
Simulation von Schnee
(2015)
Physic simulations allow the creation of dynamic scenes on the computer. Computer generated images become lively and find use in movies, games and engineering applications. GPGPU techniques make use of the graphics card to simulate physics. The simulation of dynamic snow is still little researched. The Material Point Method is the first technique which is capable of showing the dynamics andrncharacteristics of snow.
The hybrid use of Lagrangian particles and a regular cartesian grid enables solving of partial differential equations. Therefore articles are transformed to the grid. The grid velocities can then be updated with the calculation of gradients in an FEM-manner (finite element method). Finally grid node velocities are weight back to the particles to move them across the scene. This method is coupled with a constitutive model to cover the dynamic nature of snow. This include collisions and breaking.
This bachelor thesis connects the recent developments in GPGPU techniques of OpenGL with the Material Point Method to efficiently simulate visually compelling, dynamic snow scenes.
Das Thema dieser Arbeit ist die Entwicklung einer hardwarebeschleunigten Einzelbildkompression zur Videoübertragung. Verfahren zur Einzelbildkompressionrn existieren bereits seit längerer Zeit. Jedoch genügen die gängigen Verfahren nicht den Anforderungen der Echtzeit und Performanz, um während einer Videoübertragung ohne spürbare Latenz zum Einsatz zu kommen. In dieser Arbeit soll einer der geläufigsten Algorithmen zur Bildkompression auf Parallelisierbarkeit, unter zu Hilfenahme der Grafikkarte, untersucht werden, um Echtzeitfähigkeit während der Kompression und Dekompression von computergenerierten Bildern zu erreichen. Die Ergebnisse werden evaluiert und in den Rahmen aktueller Verfahren parallelisierter Kompressionstechniken eingeordnet.
The mitral valve is one of the four valves in the human heart. It is located in the left heart chamber and its function is to control the blood flow from the left atrium to the left ventricle. Pathologies can lead to malfunctions of the valve so that blood can flow back to the atrium. Patients with a faulty mitral valve function may suffer from fatigue and chest pain. The functionality can be surgically restored, which is often a long and exhaustive intervention. Thorough planning is necessary to ensure a safe and effective surgery. This can be supported by creating pre-operative segmentations of the mitral valve. A post-operative analysis can determine the success of an intervention. This work will combine existing and new ideas to propose a new approach to (semi-)automatically create such valve models. The manual part can guarantee a high quality model and reliability, whereas the automatic part contributes to saving valuable labour time.
The main contributions of the automatic algorithm are an estimated semantic separation of the two leaflets of the mitral valve and an optimization process that is capable of finding a coaptation-line and -area between the leaflets. The segmentation method can perform a fully automatic segmentation of the mitral leaflets if the annulus ring is already given. The intermediate steps of this process will be integrated into a manual segmentation method so a user can guide the whole procedure. The quality of the valve models generated by the method proposed in this work will be measured by comparing them to completely manually segmented models. This will show that commonly used methods to measure the quality of a segmentation are too general and do not suffice to reflect the real quality of a model. Consequently the work at hand will introduce a set of measurements that can qualify a mitral valve segmentation in more detail and with respect to anatomical landmarks. Besides the intra-operative support for a surgeon, a segmented mitral valve provides additional benefits. The ability to patient-specifically obtain and objectively describe the valve anatomy may be the base for future medical research in this field and automation allows to process large data sets with reduced expert dependency. Further, simulation methods that use the segmented models as input may predict the outcome of a surgery.
This thesis deals with the development of an interactive Android card game. As an example, the Hebrew game Yaniv was implemented. Focus is the elaboration of required background components and the corresponding implementation in that application. Required game processes will be screened and a possible solution will be identified.
For definite isolation and classification of important features in 3D multi-attribute volume data, multidimensional transfer functions are inalienable. Yet, when using multiple dimensions, the comprehension of the data and the interaction with it become a challenge. That- because neither the control of the versatile input parameters nor the visualization in a higher dimensional space are straightforward.
The goal of this thesis is the implementation of a transfer function editor which supports the creation of a multidimensional transfer function. Therefore different visualization and interaction techniques, like Parallel Coordinates, are used. Furthermore it will be possible to choose and combine the used dimensions interactively and the rendered volume will be adapted to the user interaction in real time.
Ray Tracing enables a close to reality rendering implementation of a modelled scene. Because of its functioning, it is able to display optical phenomena and complex lighting. Though, numerous computations per pixel have to be done. In practice implementations can not achieve computer graphics" aim of real-time rendering close to 60 frames per second. Current Graphics Processing Units (GPU) allows high execution parallelism of general-purpose computations. By using the graphics-API OpenGL this parallelism can be achieved and it is possible to design and realize a Ray-Tracer, which operates entirely on the GPU. The developed approach will be extended by an Uniform Grid - a Ray-Tracing acceleration structure. Hence, a speed-up is expected.
This thesis` purpose is the implementation of Ray-Tracer, which operates completely on the GPU, and its expansion by integrating an Uniform Grid. Afterwards, the evaluation of maximum achievable performance takes place. Possible problems regarding GPU-programming will be identified and analysed.
Thematik dieser Arbeit ist das dreidimensionale Image-Warping für diffuse und reflektierende Oberflächen. Das Warpingverfahren für den reflektierenden Fall gibt es erst seit 2014. Bei diesem neuen Algorithmus treten Artefakte auf, sobald ein Bild für einen alternativen Blickwinkel auf eine sehr unebene Fläche berechnet werden soll.
In dieser Arbeit wird der Weg von einem Raytracer, der die Eingabetexturen erzeugt, über das Warpingverfahren für beide Arten der Oberflächen, bis zur Optimierung des Reflective-Warping-Verfahrens erarbeitet. Schließlich werden die Ergebnisse der Optimierung bewertet und in den aktuellen sowie zukünftigen Stand der Technik eingeordnet.
Today, augmented reality is becoming more and more important in several areas like industrial sectors, medicine, or tourism. This gain of importance can easily be explained by its powerful extension of real world content. Therefore, augmented realty became a way to explain and enhance the real world information. Yet, to create a system which can enhance a scene with additional information, the relation between the system and the real world must be known. In order to establish this relationship a commonly used method is optical tracking. The system calculates its relation to the real world from camera images. To do so, a reference which is known is needed in the scene to serve as an orientation. Today, this is mostly a 2D-marker or a 2D-texture. These are placed in the real world scenery to serve as a reference. But, this is an intrusion in the scene. That is why it is desirable that the system works without such an additional aid. An strategy without manipulating the scene is object-tracking. In this approach, any object from the scene can be used as a reference for the system. As an object is far more complex than a marker, it is harder for the system to establish its relationship with the real world. That is why most methods for 3D-object-tracking reduce the object by not using the whole object as reference. The focus of this thesis is to research how a whole object can be used as a reference in a way that either the system or the camera can be moved in any 360 degree angle around the object without loosing the relation to the real world. As a basis the augmented reality framework, the so called VisionLib, is used. Extensions to this system for 360 degree tracking are implemented in different ways and analyzed in the scope of this work. Also, the different extensions are compared. The best results were achieved by improving the reinitialization process. With this extension, current camera images of the scene are given to the system. With the hek of these images, the system can calculate the relation to the real world faster in case the relation went missing.
The present work introduces a rigid-body physics engine, focusing on the collision detection by GPU. The increasing performance and accessibility of modern graphics cards ensures that they can be also used for algorithms that are meant not only for imaging. This advantage is used to implement an efficient collision detection based on particles. The performance differences between CPU and GPU are presented by using a test environment.
Zusätzlich zum Rendern wird die Rechenleistung moderner Grafikkarten immer häufiger auch für allgemeine Berechnungen (GPGPU) genutzt. Für die Umsetzung stehen verschiedene Möglichkeiten zur Verfügung, die von der Verwendung der Renderingpipeline bis zu eigenständigen Schnittstellen reichen. In dieser Arbeit werden mit Render-To-Texture, Transform Feedback, Compute Shader und OpenCL vier verschiedene GPGPU-Methoden untersucht. Anhand von Partikelsystemen werden sie hinsichtlich der benötigten Berechnungszeit, der GPU-Auslastung, Lines of Code und Portierbarkeit miteinander verglichen. Dazu wurden sowohl das N-Körper Problem, Smoothed Particle Hydrodynamics und ein Partikelschwarm als Partikelsysteme umgesetzt. Es konnte gezeigt werden, dass insbesondere OpenCL und Compute Shader sehr gute Ergebnisse liefern.