Bachelor Thesis
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- Bachelor Thesis (100) (remove)
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- Institut für Computervisualistik (100) (remove)
The mitral valve is one of four human heart valves. It is located in the left heart and acts as a unidirectional passageway for blood between the left atrium and the left ventricle. A correctly functioning mitral valve prevents a backflow of blood into the pulmonary circulation (lungs) and thus constitutes a vital part of the cardiac cycle. Pathologies of the mitral valve can manifest in a variety of symptoms with severity ranging from chest pain and fatigue to pulmonary edema (fluid accumulation in the tissue and air space of lungs), which may ultimately cause respiratory failure.
Malfunctioning mitral valves can be restored through complex surgical interventions, which greatly benefit from intensive planning and pre-operative analysis. Visualization techniques provide a possibility to enhance such preparation processes and can also facilitate post-operative evaluation. The work at hand extends current research in this field, building upon patient-specific mitral valve segmentations developed at the German Cancer Research Center, which result in triangulated 3D models of the valve surface. The core of this work will be the construction of a 2D-view of these models through global parameterization, a method that can be used to establish a bijective mapping between a planar parameter domain and a surface embedded in higher dimensions.
A flat representation of the mitral valve provides physicians with a view of the whole surface at once, similar to a map. This allows assessment of the valve's area and shape without the need for different viewing angles. Parts of the valve that are occluded by geometry in 3D become visible in 2D.
An additional contribution of this work will be the exploration of different visualizations of the 3D and 2D mitral valve representations. Features of the valve can be highlighted by associating them with specified colors, which can for instance directly convey pathology indicators.
Quality and effectiveness of the proposed methods were evaluated through a survey conducted at the Heidelberg University Hospital.
This work describes a novel software tool for visualizing anatomical segmentations of medical images. It was developed as part of a bachelor's thesis project, with a view to supporting research into automatic anatomical brain image segmentation. The tool builds on a widely-used visualization approach for 3D image volumes, where sections in orthogonal directions are rendered on screen as 2D images. It implements novel display modes that solve common problems with conventional viewer programs. In particular, it features a double-contour display mode to aid the user's spatial orientation in the image, as well as modes for comparing two competing segmentation labels pertaining to one and the same anatomical region. The tool was developed as an extension to an existing open-source software suite for medical image processing. The visualization modes are, however, suitable for implementation in the context of other viewer programs that follow a similar rendering approach.
The modified code can be found here: soundray.org/mm-segmentation-visualization.tar.gz.
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.
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.
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.
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.
The goal of this bachelor thesis was to add an image processing step to the music recognition software AudiVeris, in order to extract data even from faulty music sheet images. The procedure starts with a binarization using a regional version of Otsu's method. Following this the music sheet is searched for possible bendings, similar to those a hardcover book would cause. To achieve this the Hough transform is used for line detection and the k-means algorithm for cluster detection. Thereafter the music image is straightened using the discovered curvature.
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.
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.
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.
This thesis explores a 3D object detection and pose estimation approach based on the point pair features method presented by Drost et. al. [Dro+10]. While pose estimation methods have shown good improvements, they still remain a crucial problem on the computer vision field. In this work, we implemented a program that takes point cloud scenes as input and returns the detected object with their estimated pose. The program fully covers an object detection pipeline by processing 3D models during an offline phase, extracting their point pair features and creating a global descriptor out of them. During an online phase, the same features are extracted from a point cloud scene and are matched to the model features. After the voting scheme, potential poses of the object are retrieved. The poses end being clustered together and post-processed to finally deliver a result. The program was tested using simulated and real data. We evaluate these tests and present the final results, by discussing the achieved accuracy of the detections and the estimated poses.