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  • 1.
    Karlsson, Johan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Selegård, Mikael
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rendering Realistic Augmented Objects Using a Image Based Lighting Approach2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Augmented Reality (AR), the combination of real and virtual worlds, is a growing area in computer graphics. Until now, most of the focus has been on placing synthetic objects in the right position with regards to the real world, and to explor the possibilities of human interaction within the two worlds. This thesis presents the fact that virtual objects must not only be placed correctly but also lit truthfully in order to achieve a good degree of immersion. Conventional rendering techniques such as ray-tracing and radiosity requires intensive calculations and preparations for satisfying results. Hence, they are less usable for AR that demands calculations to perform in real time. We present a framework for rendering the synthetic objects using captured lighting conditions in real time. We use improved standard techniques for shadowing and lighting that we adapt for the use in a dynamic AR system as well as recent techniques of image based lighting.

  • 2.
    Malmström, Therese
    et al.
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Svedjeholm, Sanna
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Heteronormativitet – en begreppsanalys: ”Alla är både offer och supportrar av systemet”2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The concept heteronormativity was used in the literature for the first time in 1993. This term can be found in dictionaries and encyclopedias from 2006 but only in a few of the most modern publications. The term currently lacks an exact definition. The aim of concept analysis is to identify characteristics for a term by studying its use. Healthcare relations can and should be developed into a caring relation, which is dependent on a connection involving body, mind and soul between the caregiver and the patient. The aim of this work was to describe and deepen the understanding of the term heteronormativity from a healthcare perspective. Rodgers’ evolutionary concept analysis of 23 scientific papers and common newspapers resulted in seven defined attributes: assumptions, norms, social hierarchies, sanctions for those deviating from the norm, gender roles, sexual relationships and stereotype family apprehension. The analysis also identified what precedes the concept, two women working with the concept and five related concepts: equality, gender, power, discrimination and homophobia. A number of consequences of which all were negative for both individuals and the society were found. Healthcare is negatively influenced in several ways by heteronormativity rendering the caring relation impossible. Conclusion: Heteronormativity leads to a number of problems and everyone are both victims and supporters of the system.

  • 3.
    Wolmerud, Markus
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Real-Time Fluid Simulation and Visualization2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents a method based on Smoothed Particle Hydrodynamics to simulate sparse particle systems with fluid like properties in real-time. The simulation supports interactions with terrain and objects and is scaled depending on activity of the fluid. We use a carpet method on the GPU to visualize the water surface with translucency, reflection, refraction and added topology. Splash effects and foam are imitated and added as a last step.

  • 4.
    Zeitler, Jonas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Adaptive rendering of celestial bodies in WebGL2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report covers theory and comparison of techniques for rendering massive scale 3D geospa- tial planet data in a web browser. It also presents implementation details of a few of these tech- niques in WebGL and Javascript, using the Three.js [1] 3D library. The thesis project is part of the implementation of Unitea, a web based education platform for interactive astronomy visualizations. Unitea is a derivative of Uniview, which is a fulldome interactive simulation of the universe. A major part of this thesis is dedicated to the implementa- tion of Hierarchical Level of Detail (HLOD) modules for Three.js based on the theory presented by T. Ulrich [2] and later generalized by Cozzi and Ring [3]. HLOD techniques are dynamic level of detail algorithms that represent the surface of objects as accurately as possible from a certain viewing angle. By using space partitioning tree-structures, view based error metrics and culling techniques detailed representations of the objects (in this case planets) can be efficiently rendered in real-time. The modules developed provide a general-purpose library for rendering planets (or other spher- ical objects) with dynamic level of detail in Three.js. The library also features connections to online web map services (WMS) and tile services.

  • 5.
    Andersson, Simon
    et al.
    Linköping University, The Tema Institute. Linköping University, Faculty of Arts and Sciences.
    Rundström, Robin
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Kommunikation av ekologiskt livsmedel: En intervju- och textanalysstudie av hur ekologiskt livsmedel kommuniceras mot konsumenter2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study focuses on the rhetorical rendering of organic foods, within the research area of environmental communication and ecological theories. The aim is to analyse which renderings are connected to the concept organic foods. Further on Swedish authorities and organisations views on organic foods are examined, in comparison to the grocery retailer’s rhetorical rendering of organic foods. The methodology is based on two methods of data collection. Qualitative research interviews have been conducted with the following authorities: the Swedish Food Agency, the Swedish Consumer Agency and the Swedish Board of Agriculture. Interviews were also conducted with the organisations KRAV and the Swedish Society for Nature Conservation. The interviews were conducted with the intention of making visible the underlying rendering of the concept of organic foods. A textual and metaphor analyses of ICA, Coop and Axfood’s combined communication of organic foods were performed. The aim with these analyses is to examine the grocery retailer’s rhetorical rendering of the concept. The study highlights that there are two main attitudes towards the rendering of organic foods among the actors. Additionally this study clarifies that the authorities, organisations and grocery retailer’s use of the concept differ. Partly the authorities rendering of organics are mainly focused around environmental benefits. While the grocery retailers rendering of organic foods is based on metaphors and idyllic nature values. The study also shows that organic labels is part of green consumerism and thereby legitimize consumption as a solution of environmental and social problems. 

  • 6.
    Stenbeck, Marcus
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Automatisk testning av WebGL på mobil- och desktopenheter2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    WebGL is a standard for drawing graphics in a web browser. Currently it isn’t widely understood how consistently WebGL performs across a majority of the de- vices that support it. Determining if an image looks correct to a human observer is an interesting problem. The solution for this is useful when developing WebGL applications, since a developer could make better informed decisions during de- velopment. The differences in capability between WebGL implementations are studied, and a few factors are selected that likely will contribute to variations in the rendered output. These factors are found by studying the WebGL specification documen- tation, and in the cases where it is ambiguous, further, authorative sources have contributed to the choice of factors studied. A prototype testing system is developed, including a tool for simulating imple- mentation differences. Two image processing algorithms are evaluated for their suitability in an automatic testing system. For testing, four test cases are devel- oped. The testing system is run with the test cases on wide range of devices, both mobile and desktop. The results show that image processing is not suitable alone the source for deter- mining a test success or failure. However, some promise is shown in using image processing as one component in a fully automatic testing system. Furthermore, developing test cases that perform as the test constructor intends is proven to be a challenge in itself.

  • 7.
    Sand, Victor
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Dynamic Visualization of Space Weather Simulation Data2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The work described in this thesis is part of the Open Space project, a collaboration between Linköping University, NASA and the American Museum of Natural History. The long-term goal of Open Space is a multi-purpose, open-source scientific visualization software. The thesis covers the research and implementation of a pipeline for preparing and rendering volumetric data. The developed pipeline consists of three stages: A data formatting stage which takes data from various sources and prepares it for the rest of the pipeline, a pre-processing stage which builds a tree structure of of the raw data, and finally an interactive rendering stage which draws a volume using ray-casting. The pipeline is a fully working proof-of-concept for future development of Open Space, and can be used as-is to render space weather data using a combination of suitable data structures and an efficient data transfer pipeline. Many concepts and ideas from this work can be utilized in the larger-scale software project.

  • 8.
    Felekidis, Dimitrios
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Advanced Visualization Techniques for Laparoscopic Liver Surgery2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Laparoscopic liver surgery is mainly preferred over the traditional open liver surgery due to its unquestionable benefits. This type of surgery is executed by inserting an endoscope camera and the surgical tools inside the patient’s body through small incisions. The surgeons perform the operation by watching the video transmitted from the endoscope camera to high-resolution monitors. The location of the tumors and cysts is examined before and during the operation by the surgeons from the pre-operative CT scans displayed on a different monitor or on printed copies making the operation more difficult to perform.

    In order to make it easier for the surgeons to locate the tumors and cysts and have an insight for the rest of the inner structures of the liver, the 3D models of the liver’s inner structures are extracted from the preoperative CT scans and are overlaid on to the live video stream transmitted from the endoscope camera during the operation, a technique known as virtual X-ray. In that way the surgeons can virtually look into the liver and locate the tumors and cysts (focus objects) and also have a basic understanding of their spatial relation with other critical structures. The current master thesis focuses on enhancing the depth and spatial perception between the focus objects and their surrounding areas when they are overlaid on to the live endoscope video stream. That is achieved by placing a cone on the position of each focus object facing the camera. The cone creates an intersection surface (cut volume) that cuts the structures that lay in it, visualizing the depth of the cut and the spatial relation between the focus object and the intersected structures. The positioning of the cones is calculated automatically according to the center points of the focus objects but the sizes of the cones are user defined with bigger sizes revealing more of the surrounding area. The rest of the structures that are not part of any cut volume are not discarded but handled in such way that still depict their spatial relation with the rest of the structures. Different rendering results are presented for a laparoscopic liver test surgery in which a plastic liver model was used. The results include different presets of the cut volumes’ characteristics. Additionally, the same technique can be applied on the 3D liver’s surface instead of the live endoscope image and provide depth and spatial information. Results from that case are also presented.

  • 9.
    Hiltunen, Mattias
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Olander, Robin
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Visualisering på arkitektkontor, En effektivitetsjämförelse mellan fyra visualiseringsprogram2014Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Idag har det blivit allt vanligare att visualisering tillämpas inom byggsektorn. Det finns en mängd olika program där det kan vara stora skillnader på användarvänlighet samt kvalitet på de bilder programmen producerar. Några av de program som används på många arkitektkontor är Revit, ArchiCad, 3DS Max Design och Lumion. Ett stort problem idag är att för att få bra säljande bilder kostar det ofta mer än vad det är möjligt att ta betalt.

    Syftet med detta examensarbete är att ta reda på vilka visualiseringsprogram som är effektivast med avseende på tid, kostnad, användarvänlighet och resultat för ett arkitektkontor då de vill ha säljande bilder. Syftet är även att presentera ett förslag för vilket program ett arkitektkontor får ut mest av att använda och om det är värt att investera i ny programvara. Studien avser arkitektkontor utan visualiseringsenhet. Studien som görs är tänkt som en utvärdering och uppdraget kommer att utföras åt Sonark Arkitektkontor AB.

    För att besvara detta syfte har följande frågeställningar formulerats:

    • Vilket/vilka av programmen 3DS Max Design, Lumion, Revit och ArchiCad lämpar sig bäst till att ta fram fotorealistiska bilder på ett arkitektkontor och varför?
    • Finns det ett samband mellan god användarvänlighet och kvalitet?
    • Vilket program är det mest effektiva med avseende på tid, kostnad, användarvänlighetoch kvalitet?

    Genom att utgå ifrån att samma visualisering ska göras med samtliga program blir det möjligt att jämföra resultatet och därmed kunna lämna en rekommendation. I samtliga program har ett hus med tillhörande komponenter valts ut. Detta hus har sedan visualiserats i de fyra programmen. Tiden för visualisering och rendering har mätts och jämförts, likaså kostnaden. För att jämföra användarvänlighet och kvalitet har bedömningsmallar upprättats.

    Resultatet av användarvänlighet visar att Lumion är det bästa i just den kategorin tätt följt av ArchiCad som bara kom en poäng efter. 3DS max design och Revit kom på delad tredje plats, en poäng bakom tvåan.

    I kvalitetstestet vann 3DS Max Design med några enstaka poäng mer än Revit. På tredje plats en bra bit efter tvåan kom Lumion och på fjärde plats ArchiCad.

    Utifrån de betygsmallar, de största för- respektive nackdelar som finns för varje program samt vår egen upplevelse har bedömning skett om programmen rekommenderas och vilket som är det mest effektiva. De program som fick stämpeln “Bäst effektivitet” samt ”Rekommenderas” blev följande:

    • Bäst effektivitet: Revit
    • Rekommenderas: Lumion och 3DS max design
  • 10.
    Ekman, Viktor
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Moen, Jesper
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Exteriör och interiör visualisering av ett bostadshus i 3ds max2014Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Denna rapport beskriver och drar jämförelser mellan olika visualiseringstekniker i 3D Studio Max och Adobe Photoshop CS3. Syftet med studien är att undersöka olika visualiserings- och renderingstekniker för att se vilka tekniker som ger ett smidigast och mest verklighetstroget resultat utifrån olika förutsättningar. Studien grundar sig på en huvudfråga och två stycken underfrågor. Hur skapar man ett effektivt och verklighetstroget visualiseringsresultat av ett bostadskvarter för intressenter? • Vilka fördelar och nackdelar finns det med olika visualiseringstekniker? • Vilka metoder ger ett verklighetstroget visualiseringsresultat vid interiör respektive exteriör visualisering? Slutsatsen med studien är att varje situation är unik och att det finns fördelar och nackdelar med varje teknik och metod i de olika programmen. För att nå ett önskat slutresultat så gäller det att lära sig hur varje metod fungerar och sedan anpassa den utifrån varje enskild situation.

  • 11.
    Ek, Nathalie
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Realtidsrendering av försimulerade partiklar2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis presents a method for real-time streaming of pre-simulated particle systems. The particle systems are simulated offline in any software and then saved as an Alembic file. This Alembic file is then imported into Frostbite and can be loaded at run-time. The result of this master the- sis work is the implementation of a streaming and rendering framework for pre-simulated particles. The implementation contains only basic shad- ing and lighting due to the time constraints of the work but the streaming part features an advanced solution to get predictable and manageable CPU and memory overhead. The implentation performs well and works satisfac- tory.

  • 12.
    Tsirikoglou, Apostolia
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Efficient Simulation and Rendering of Sub-surface Scattering2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, a new improved V-Ray subsurface scattering shader based on the improved diffusion theory is proposed. The new shader supports the better dipole and the quantized diffusion reflectance model for layered translucent materials. These new implemented models build on previous diffusion BSSRDFs and in the case of quantized diffusion uses an extended source function for the material layer. One of the main contributions and significant improvement over V-Ray’s existing subsurface scattering shader is the front and back subsurface scattering separation. This was achieved by dividing the illumination map that is used to calculate each shading’s point color, in two parts: the front part that comes of front lighting and the back one that comes of back lighting. Thus, the subsurface scattering layer can be divided in its consisting parts and each of them can be controlled, weighted and used independently. Finally, the project’s outcome is a new V-Ray material that provides all the above improvements in an intuitive, practical and efficient shader with several intuitive algorithm and light map controls, where artists can create subsurface scattering effects through three subsurface scattering layers.

  • 13.
    Törnros, Martin
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Interactive visualization of space weather data2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This work serves to present the background, approach, and selected results for the initial master thesis and prototyping phase of Open Space, a joint visualization software development project by National Aeronautics and Space Administration (NASA), Linköping University (LiU) and the American Museum of Natural History (AMNH). The thesis report provides a theoretical introduction to heliophysics, modeling of space weather events, volumetric rendering, and an understanding of how these relate in the bigger scope of Open Space. A set of visualization tools that are currently used at NASA and AMNH are presented and discussed. These tools are used to visualize global heliosphere models, both for scientific studies and for public presentations, and are mainly making use of geometric rendering techniques. The paper will, in detail, describe a new approach to visualize the science models with volumetric rendering to better represent the volumetric structure of the data. Custom processors have been developed for the open source volumetric rendering engine Voreen, to load and visualize science models provided by the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center (GSFC). Selected parts of the code are presented by C++ code examples. To best represent models that are defined in non-Cartesian space, a new approach to volumetric rendering is presented and discussed. Compared to the traditional approach of transforming such models to Cartesian space, this new approach performs no such model transformations, and thus minimizes the amount of empty voxels and introduces less interpolation artifacts. Final results are presented as rendered images and are discussed from a scientific visualization perspective, taking into account the physics representation, potential rendering artifacts, and the rendering performance.

  • 14.
    Thellman, Sam
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Arts and Sciences.
    Assessing the Representational Capacity of Haptics in a Human-Computer Interface2013Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis was to contribute to our knowledge of what haptics can bring to the table as a human-computer interface rendering technique, which other rendering techniques cannot. An experiment was set up in which a multi-interfaced game was used to convey an information structure to interface users. Each of the game’s three user interfaces utilized one of three different rendering techniques: haptic rendering, graphic rendering, and graphic-haptic rendering. The capacity of each rendering technique to represent the information structure was assessed in terms of the effect of the corresponding interface on three aspects of the user interaction: user performance, user satisfaction and system usability.

    The result indicated that user performance benefitted from a graphic or graphic-haptic rendering over a haptic rendering. There were no differences between the rendering techniques with regards to the overall user satisfaction. However, there were notable differences on the user satisfaction metric subscale level. The haptic rendering required higher attentive effort than other renderings. Also, the graphic rendering better facilitated the perception of having clear goals and feedback. The results also suggested that the overall system usability benefitted from a graphic or graphic-haptic rendering over a haptic rendering.

  • 15.
    Englund, Rickard
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ultrasound Surface Extraction for Advanced Skin Rendering2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report evaluates possibilities to combine volumetric ultrasound (us) data together with the recent work published on advanced skin rendering techniques. We focus mainly on how to filter us data and localize surfaces within us data. We also evaluate recent skin rendering techniques in order to have a good understanding of what is needed from the us for rendering realistic skin. us data is acquired using sonography and have a low signal-to-noise ratio by nature, this makes it harder to extract surfaces compared to other medical data acquisition methods such as ct and mr. This report present an algorithm which implements a variational classification technique to emphasize surfaces within us and using a rbf network to fit an implicit function to these surfaces. Using this approach presented we have successfully extract smooth meshes from the noisy us data.

  • 16.
    Hulth, Anna-Karin
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Melakari, Erik
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    IBR camera system for live TV sport productions2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The mix of regular sport production and new digital techniques can give the audience a more spectacular viewing experience. Nowadays, for example, commercial banners can be virtually added onto the arenas, and statistical information, such as shot speed in soccer games, lengths in athletics and yards in

    American football, can be calculated and visualized during the events. A dream scenario for many sport producers would be to have a virtual camera system that can give a free viewpoint of the events delivered in real-time. A virtual camera system can render a new viewpoint of the scenery using only existing image material as input. This kind of system would be able to produce more spectacular images and give the audience a clearer view of the events taking place.

    The purpose with this thesis work is to investigate whether Image Based Rendering techniques can be used to produce such a system and what the difficulties and the restrictions from the broadcasting techniques are. Based on a theoretical background and interviews with Swedish sport producers a software system for the virtual camera was designed. This system was then evaluated based on three tests performed. At the moment the system is unable to fulfil all of the requests set up by the producers.

    An important part of the work has therefore been to make suggestions on further improvements that can increase the system performance.

  • 17.
    Lagerkvist, Rebecca
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Mesh simplification of complex VRML models2005Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a large part of their work Volvo Cars uses digital models - in the design process, geometry simulation, safety tests, presentation material etc. The models may be used for many purposes but they are normally only produced in one level of detail. In general, the level that suits the most extreme demands. High resolution models challenge rendering performances, transmission bandwidth and storage capacities. At Volvo Cars there is time, money and energy to be saved by adapting the the model’s level of detail to their area of usage.

    The aim of this thesis is to investigate if the Volvo Cars models can be reduced to containing less than 20% of its original triangles without compromising too much in quality. In the thesis, the mesh simplification field is researched and the simplification algorithm judged to best suit the needs of Volvo Cars is implemented in a C++ program. The program is used to test and analyze the Volvo Cars’ models.

    The results show that it is possible to take away more than 80% of the the model’s polygons hardly without affecting the appearance.

  • 18.
    Engström, Philip
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Interactive GPU-based Volume Rendering2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Modern GPUs possess enormous computational capabilities, power that has just become available for general purpose programming via the development of highly programmable shaders. This thesis investigates ways to use this power for the purpose of medical visualization.

    The project was carried out in collaboration with Sectra Imtec, a Linköpingbased medical imaging company. The problem to be solved was how best to render high quality images at interactive frame rates for the purpose of previewing a medical data set. Two different GPU-accelerated volume rendering approaches were investigated and implemented. One approach based on textured slices of proxy geometry, and one based on ray casting.

    It is shown that the ray casting implementation presented far superior image quality. Because of this, most of the work during the project concerned improving the method enough to make the visualization interactive. In particular, an empty space skipping method via a complex bounding geometry was implemented and is described in detail.

    This report also presents important background facts regarding volume rendering and modern graphics cards, so that it is accessible for any reader with basic computer graphics knowledge.

  • 19.
    Khoury, Richard
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Spatially Varying IBL Using Light Probe Sequences2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Visual media, such as film and computer games, often require the need for the realistic rendering of synthetic objects. Image Based Lighting (IBL) techniques provide methods for applying measured real-world lighting to synthetic objects, making them appear believable within their environment. Given this ability, IBL techniques have drawn interest within many industries involved in visual effects, however its adoption has been mostly confined to implementations of its original method.

    Traditional IBL, as it is now known, only requires the measurement of light at one position in space to provide the data for illuminating all synthetic objects in the scene. This single requirement places large constraints on the complexity of illumination within a scene by assuming there are negligible changes in lighting within the extent of the local environment. Due to this, lighting features such as shadows, that exhibit a spatial frequency greater than zero, cannot be represented within this limited model.

    Modern research into IBL techniques aim to resolve this problem by presenting methods to capture, process, and render spatially varying illumination. This thesis builds upon recent research into densely sampled light probe sequences and considers its use in a production environment. Its objective is to present set of tools for processing and rendering this data for use with the commercial software packages Maya, a modelling and animation application, and mental ray, a high-fidelity renderer.

  • 20.
    Tarigan, Jos Timanta
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Pre-computed surface radiance transfer2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rendering a complex global illumination scene requires an extensive computational resource. It is hard to achieve a real time rendering of a complex object using explicit 3D information. To tackle this obstacle, many techniques have been introduced to close the gap between complex 3D scene and real time rendering. One of the proposed solutions is using an image-based rendering technique. Image-based rendering is a method to achieve the desired image by referencing the sampled image as a source.

    This thesis will focus on a mix between image-based rendering and geometrybased rendering. Instead of rendering directly using a global illumination method, we use a set of image, which are captured during the offline rendering. We call the firstprocess as light transport pre-calculation process. These images then treated as a texture and will be attached to the polygon during the online rendering process. Based on the viewer position, the system decides which value to attach on the polygon. This rendering process however requires a lot of calculation. Luckily, recent graphic card allows developer to exploit GPU‟s hardware by making it possible to reprogram the rendering pipeline. As a graphic dedicated hardware, GPU has a lot of advantage to do a rendering compared to CPU. For example its nature of parallel processing is an advantage considering most of rendering process is a parallel processing. Other than splitting the computational task, we also would like to see how we can use the availability of memory. This can be done by processing the scene before the rendering process took place.

    This thesis will discuss and implement how to split the burden of processing power by rendering a pre-calculated data for later render. Since the pre-rendered data could be huge, it is also important to discuss a compression method that can be applied in GPU architecture and fast enough to be rendered as a real time.

    Keywords: Pre-computed Surface Radiance Transfer, Global Illumination, BRDF, Image Based Modeling and Rendering, Real Time Rendering, GPU Programming, GLSL.

  • 21.
    Mensmann, Jörg
    et al.
    University of Münster, Germany.
    Ropinski,, Timo
    University of Münster, Germany.
    Hinrichs, Klaus
    University of Münster, Germany.
    An Advanced Volume Raycasting Technique using GPU Stream Processing2010In: Computer Graphics Theory and Applications, GRAPP 2010, 2010, 190-198 p.Conference paper (Other academic)
    Abstract [en]

    GPU-based raycasting is the state-of-the-art rendering technique for interactive volume visualization. The ray traversal is usually implemented in a fragment shader, utilizing the hardware in a way that was not originally intended. New programming interfaces for stream processing, such as CUDA, support a more general programming model and the use of additional device features, which are not accessible through traditional shader programming. In this paper we propose a slab-based raycasting technique that is modeled specifically to use these features to accelerate volume rendering. This technique is based on experience gained from comparing fragment shader implementations of basic raycasting to implementations directly translated to CUDA kernels. The comparison covers direct volume rendering with a variety of optional features, e.g., gradient and lighting calculations. Our findings are supported by benchmarks of typical volume visualization scenarios. We conclude that new stream processing models can only gain a small performance advantage when directly porting the basic raycasting algorithm. However, they can be advantageous through novel acceleration methods which use the hardware features not available to shader implementations.

  • 22.
    Liu, Bingchen
    et al.
    University of Auckland, New Zealand.
    Wuensche, Burkhard
    University of Auckland, New Zealand.
    Ropinski, Timo
    University of Münster, Germany.
    Visualization by Example - A Constructive Visual Component-Based Interface for Direct Volume Rendering2010In: GRAPP 2010, 2010, 254-259 p.Conference paper (Other academic)
    Abstract [en]

    The effectiveness of direct volume rendered images depends on finding transfer functions which emphasize structures in the underlying data. In order to support this process, we present a spreadsheet-like constructive visual component-based interface, which also allows novice users to efficiently find meaningful transfer functions. The interface uses a programming-by-example style approach and exploits the domain knowledge of the user without requiring visualization knowledge. Therefore, our application automatically analysis histograms with the Douglas-Peucker algorithm in order to identify potential structures in the data set. Sample visualizations of the resulting structures are presented to the user who can refine and combine them to more complex visualizations. Preliminary tests confirm that the interface is easy to use, and enables non-expert users to identify structures which they could not reveal with traditional transfer function editors.

  • 23.
    Nilsson, Andreas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    IBL in GUI for mobile devices2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mobile phones are here to stay, and the interaction with them is an evolving process. Designing software for mobile devices poses new challenges not seen in desktop computer environments. Screen size, performance and inputs, are just a few areas where they significantly differ. Although, intriguingly the gap between them is narrowing. Devices are now able to do things previously only restricted to PCs. The graphics chip integrated with high-end devices of today and tomorrow has capabilities worth exploring. With more power and advanced shader support, techniques such as image based lighting becomes worth exploring.

    To solve the problem described in this thesis I built a framework for image processing. This framework is further described indirectly throughout the report and is available upon request. The framework is never the focus of the report since any framework should suffice and the developed framework should not hinder the reader’s own experimentations.

    The purpose of this thesis is to see whether image based lighting (IBL) and image based rendering (IBR) is feasible with a mobile phone, as well as explore which applications it would suit for. Also, examining if it can be combined with high dynamic range imaging (HDRI) to enhance the user experience. Both IBL/IBR and HDRI might be new terms for the reader; if so I encourage you to read 2.2 for a deeper understanding.

  • 24.
    Sievert, Andreas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Tools and Algorithms for Classification in Volume Rendering of Dual Energy Data Sets2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the last few years, technology within the medical imaging sector has made many advances, which in turn has opened many new possibilities. One such recent advance is the development of imaging with data from dual energy computed tomography, CT, scanners. However, with new possibilities come new challenges.

    One challenge, that is discussed in this thesis, is rendering of images created from two volumes in an efficient way with respect to the classification of the data. Focus lies on investigating how dual energy data sets can be classified in order to fully use the potential of having volumes from two different energy levels. A critical asset in this investigation is the ability to utilize a transfer function description that extends into two dimensions. One such transfer function description is presented in detail.

    With this two-dimensional description comes the need for a new way to interact with the transfer function. How the interaction between a user and the transfer function description is implemented for Siemens Corporate Research in Princeton, NJ will also be discussed in this thesis as well as the classification results of rendering dual energy data. These results show that it is possible to classify blood vessels correctly when rendering dual energy computed tomography angiography, CTA, data.

  • 25.
    Östergaard, Johan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Planet Rendering Using Online High-Resolution Datasets2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A large amount of image datasets are publicly available online through the web map service standard. The contents of the datasets span from satellite imagery of the earth and other planets of our solar system to various scientific data.

    This thesis presents an implementation of a planet renderer streaming high resolution image and height data from online datasets. The planet renderer uses a level of detail technique based on nodes connected by a quad tree data structure. The level of detail is determined by the size of the nodes in screen coordinates which ensures a sufficient texel to pixel ratio of the image data and a reasonably consistent polygon size in screen space.

    The project will be implemented in Uniview which is an application developed by SCISS AB and is primarily used in planetarium domes to visualize the Universe. Being able to visualize the high resolution image data and scientific measurements in a dome environment will provide the viewers a greater perspective of the data.

  • 26.
    Andersson, Filip Lars Roland
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Real-Time Ray Tracing on the Cell Processor2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The first ray casting algorithm was introduced as early as 1966 and was followed by the first ray tracing algorithm in 1979. Since then many revisions to both these algorithms have been presented along with the strong development of computer processors. For a very long time both ray casting and ray tracing were associated with rendering of single images. One single image could take several hours to compute and to date still can for very complex scenes.

    Only during the last few years have attempts to write algorithms for real time been made. This thesis focuses on the question of how a real time ray caster can be mapped on the Cell Broadband Engine Architecture. It addresses the development of a ray caster on a single unit processor and then goes through the steps on how to rewrite an application to exploit the full potential of the cell broadband engine. This includes identifying the compute intensive parts of the application and parallelizing these over all the available elements in the cell architecture.

  • 27.
    Lindholm, Stefan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Large fused GPU volume rendering2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis describes the underlying theory and implementation of a fused GPU volume rendering pipeline. The open source framework of XIP, largely developed at Siemens Corporate Research, is extended with fusion capabilities through a Binary Space Partitioning approach. Regions in the intersection pattern of multiple volumes are identified and subsequently rendered using either Texture Slicing or Raycasting in a cell based fashion. Results demonstrate interactive frame rates for reasonable scenes and are encouraging as the implementation can be extended by several key acceleration methods.

  • 28.
    Åkerlund, Oskar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Clustered Importance Sampling for Fast Reflectance Rendering2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In realistic image synthesis, a major challenge is how to account for largescale, complex lighting environments in an ecient and robust way. This thesis presents a simple and ecient method for bidirectional importance sampling from large-scale illumination sources.

    The method is based on a clustered representation of the potential light source samples. Combined with an ecient BRDF sampling strategy, an importance function can rapidly be constructed and used to select the lighting samples that will contribute the most in the rendering equation. Most existing methods similar to the one presented in this thesis are restricted to environment lighting only; in contrast, the proposed algorithm can also be used in local lighting scenarios where the illumination exists on an unstructured point set, which may not have the same natural parameterization as an environment map.

  • 29.
    Mishra, Sushmit
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research.
    Lunner, Thomas
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research.
    Stenfelt, Stefan
    Linköping University, Department of Clinical and Experimental Medicine.
    Rönnberg, Jerker
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research.
    Rudner, Mary
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning, Disability Research.
    Audiovisual presentation supports cognitive processing of information heard in modulated noise2013Conference paper (Other academic)
    Abstract [en]

    The cognitive spare capacity test (CSCT) assesses the ability to process heard information stored in working memory. This is important because listening that is effortful, due to noise or hearing impairment, consumes cognitive resources leaving less capacity available for further processing. The CSCT pinpoints the effects of modality of presentation (Audiovisual, Audio-only); memory load (High, Low) and different kinds of executive processing demands (Updating, Inhibition). In the present study, 24 participants with mild to moderate hearing loss performed CSCT with amplification in quiet, in steady-state noise at an individually adapted signal to noise ratio (SNR) rendering intelligibility of ~95% and in modulated noise (International Speech Test Signal; ISTS) at the same SNR. An independent battery of cognitive tests was also administered. Analysis of variance showed main effects of all factors, including better performance with Audiovisual than Audio-only modality. However, a significant interaction revealed that the Audiovisual benefit was most prominent in ISTS. The benefit of Audiovisual presentation over Audio-only presentation correlated with the independent measure of working memory capacity. The pattern of results suggests that for the hearing impaired population, Audiovisual presentation supports cognitive processing of information heard in modulated noise and that the magnitude of this benefit is related to working memory capacity.

  • 30.
    Högberg, Nils
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Larsson, Per
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Building a Pipeline for Gathering and Rendering With Spatially Variant Incident Illumination Using Real Time Video Light Probes2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lighting plays an important part in computer graphics. When making photo realistic renderings the ultimate goal is to generate an image that would be indistinguishable from a real photograph or to seamlessly integrate a synthetic object into a photo. One of the key elements is to get correct lighting and shading in the rendering since the human vision is very well attuned to subtile variations of the lighting.

    Recent image based techniques has been developed that uses high dynamic range omni directional images, light probes, from the real world as light information to illuminate synthetic objects. Such images are capturing the incident light information in the point it was taken. By using these images as lighting information the objects illuminated will integrate seamlessly into a background photography of the scene. However these techniques assumes that the lighting is spatially constant throughout the scene.

    By using more light probes spatial variations in the scene can be captured. We will here present a pipeline for capturing and rendering with spatially variant light probes using a device that can capture light probes at very high dynamic range. Using this pipeline we have captured high frequency variations in a scene and scenes with complex real world lighting and used this information to render objects representing these variations.

  • 31.
    Cervin, Albert
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Adaptive Hardware-accelerated Terrain Tessellation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this master thesis report, a scheme for adaptive hardware terrain tessellation is presented. The scheme uses an offline processing approach where a height map is analyzed in terms of curvature and the result is stored in a resource called density map. This density map is then bound as a resource to the hardware tessellation stage and used to bias the tessellation factor for a given edge. The scheme is implemented inside FrostbiteTM2 by EATM DICETM and produces good results while making the heightfield rendering more efficient. The performance gain can be used to increase the rendering detail, allowing for better visual appearance for the terrain mesh. The scheme is currently implemented for hardware tessellation but could also be used for software terrain mesh generation. The implementation works satisfactory and produces good results with a reasonable speed.

  • 32.
    Ekelin, Jonna
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Fernqvist, Lena
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lighting and Graphics Effects for Real-Time Visualization of the Universe2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This work has been performed at SCISS AB, a company situated in Norrk öping and whose business lies in developing platforms for graphics visualization. SCISS's main software product, UniView, is a fully interactive system allowing the user to explore all parts of the observable universe, from rocks on the surface of a planet to galaxies and quasars in outer space. It is used mainly for astronomical and scientic presentation.

    The aim of this work has been to enhance the visual appearance of lighting eects in the solar system, which has included implementing atmospheric eects for planets, shadow casting and an enhanced representation of the sun. We have managed to implement a visually convincing atmosphere applicable to all of the planets in the solar system. The atmospheric eects can be viewed from space as well as from the surface of a planet and allow for a seamless transition between the two locations. The atmosphere simulates the eects of day and night, sunrise and sunset, and gives important depth cues through the eect of aerial perspective.

    Combining the atmospheric eects with an algorithm for rendering accurate soft shadows for spherical objects and a sun that varies in size with visibility has enabled the visualization of the phenomena of solar and lunar eclipses. This feature can be watched from space, where the shape of the shadow becomes apparent and can be studied, as well as from the planet's surface, where one can experience the darkening of the sky as the moon slowly obscures the sun and then observe the corona of the sun around the dark moon. All this can be run at interactive frame rates on ATI and Nvidia graphics cards using shader model 2.0 or above.

  • 33.
    Edling, Andréas
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Franke, Jonas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    IBR camera system for live TV production2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Traditional television and video recordings are limited to show only views of a scene from were a camera is positioned. For certain situations, positioning a camera at the most attractive viewpoints might not be possible, such as above a crowd at a concert. In this thesis, technologies for alleviating this limitation, and extending traditional filming processes, by using video-based rendering methods are investigated. With such video-based rendering methods, given a set of existing cameras, images from novel viewpoints can be produced without having any capturing device at the chosen viewpoint.

    This thesis investigates the current state of image and video-based systems for creating virtual camera views, which techniques are used in different approaches, and what the current limitations are. Furthermore, an implementation of a virtual camera system is created which can be run on consumer graphics hardware. By merging geometries from different cameras, calculated with a stereo algorithm, a representation of the current scene can be rendered. The viewpoint can be changed by a user interactively in real-time.

  • 34.
    Bernhardsson, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Sörensen, Christian
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Realtime Volume Visualization of Time Evolving Nebulae for Immersive Environments2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper presents the result of our master thesis work in media technology, which is an implementation of a realtime volume rendering engine capable of visualizing reflection nebulae. The engine is using scattering and emission properties of time evolving volumetric data, created by astrophysicists at the Hayden Planetarium, New York. The visualization is designed towards full dome planetarium displays. Using the latest GPU based techniques for volume rendering and impostor techniques we are able to interactively fly around as well as animate several nebulae embedded in their true astronomical content.

    This paper is aimed towards fellow media technology students and people interested in the area of realtime volume renderings. It is written with the presumption that the reader has the same knowledge as we did when starting our thesis work, which implies good confidence in modern 3D computer graphics, some experience in object-oriented programming and basic knowledge of algebra and calculus. It is our hope that this report can be enjoyed even if skipping some of the more technical parts.

  • 35.
    Levén, Lina
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Integrating HDR with a Real-Time Graphics Engine2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report covers the work on integrating HDR rendering in the existing Digital Arts graphics engine and in this case the HDR rendering will come to use mainly in architectural visualization. The basics of the HDR concept is covered and the use of HDR in real-time applications is motivated and the pros and cons of different image formats are considered. The necessity of a suitable tone mapping operator is taken into account and the tone mapping operator used is the one described in the paper Perceptual Effects in Real Time Tone Mapping by Krawczyk et al and the implementation of it is considered.

  • 36.
    Ek, Joel
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    A Data-Parallel Graphics Pipeline Implemented in OpenCL2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report documents implementation details, results, benchmarks and technical discussions for the work carried out within a master’s thesis at Linköping University. Within the master’s thesis, the field of software rendering is explored in the age of parallel computing. Using the Open Computing Language, a complete graphics pipeline was implemented for use on general processing units from different vendors. The pipeline is tile-based, fully-configurable and provides means of rendering visually compelling images in real-time. Yet, further optimizations for parallel architectures are needed as uneven work loads drastically decrease the overall performance of the pipeline.

  • 37.
    Syversen, Eva
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Wayshowing i Visualiceringscenter C: Jämförelse av observationer under skyltskapande i virtuell miljo2012Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis is about wayshowing in a 3D model of Visualiseringscenter C, Norrköping. The aim is to examine different ways to make signs in a virtual environment and which of these ways is the easiest to apply for the user.

    The essay is based on theory regarding wayshowing and how a good sign should look in order to fulfill its purpose. With the use of this theory, signs have been created in a 3D environment. The collected data which the results are based on comes from two structured observations and one interview. The participant and the observer of the observations was the author herself and the interview was done with a student who has similar experiences in graphic design and 3D as the author.

    The observations evaluated two different ways to create signs. One way in which the texture was made before the signs were made in the 3D environment and one way in which the texture was made after the signs had been manufactured in the 3D environment. The results of the observations show that the latter approach is more convenient to use because it is easier to adjust the texture after the sign has been created. The observations also considered the digital processes used and the time spent on these processes. The observations revealed that rendering was the most used digital process. The digital process which was most time consuming was the use of tutorials, i.e. to acquire knowledge of how an previously unknown digital process could be performed. The observations also revealed that re-use of cameras, materials, and 3D models was time saving.

  • 38.
    Miandji, Ehsan
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Surface Light Field Generation, Compression and Rendering2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    We present a framework for generating, compressing and rendering of SurfaceLight Field (SLF) data. Our method is based on radiance data generated usingphysically based rendering methods. Thus the SLF data is generated directlyinstead of re-sampling digital photographs. Our SLF representation decouplesspatial resolution from geometric complexity. We achieve this by uniform samplingof spatial dimension of the SLF function. For compression, we use ClusteredPrincipal Component Analysis (CPCA). The SLF matrix is first clustered to lowfrequency groups of points across all directions. Then we apply PCA to eachcluster. The clustering ensures that the within-cluster frequency of data is low,allowing for projection using a few principal components. Finally we reconstructthe CPCA encoded data using an efficient rendering algorithm. Our reconstructiontechnique ensures seamless reconstruction of discrete SLF data. We applied ourrendering method for fast, high quality off-line rendering and real-time illuminationof static scenes. The proposed framework is not limited to complexity of materialsor light sources, enabling us to render high quality images describing the full globalillumination in a scene.

  • 39.
    Ländell, Karl-Rikard
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wiksten Färnström, Axel
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    FPGA Implementation of a UPnP Media Renderer2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Actiwave AB delivers audio solutions for active speakers. One of the features is that audio can be streamed to the speakers over a local network connection. The module that provides this functionality is expensive. This thesis investigates if this can instead be achieved by taking advantage of the Spartan-6 FPGA on their platform, using part of it as a MicroBlaze soft processor on which a rendering device can be implemented. The thesis discusses design decisions such as selection and integration of operating system, UPnP framework and media decoder. A fully functional prototype application for a desktop computer was implemented, with the intention of porting it to the FPGA platform. There turned out to be too many compability issues though, so instead, a simpler renderer was implemented on the FPGA. Mp3 music files were successfully streamed to and decoded on the soft processor, but without fulfilling real-time constraints. The conclusion is that it is reasonable to implement a UPnP Media Renderer on the FPGA. Decoding in real-time can be an issue due to insufficient performance of the soft processor, but several possible solutions exist.

  • 40.
    Jonsson, Erik
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Illustrative Visualization of Anatomical Structures2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Illustrative visualization is a term for visualization techniques inspired by traditional technical and medical illustration. These techniques are based on knowledge of the human perception and provide effective visual abstraction to make the visualizations more understandable. Within volume rendering these expressive visualizations can be achieved using non-photorealistic rendering that combines different levels of abstraction to convey the most important information to the viewer. In this thesis I will look at illustrative techniques and show how these can be used to visualize anatomical structures in a medical volume data. The result of the thesis is a prototype of an anatomy education application, that makes use of illustrative techniques to have a focus+context visualization with feature enhancement, tone shading and labels describing the anatomical structures. This results in an expressive visualization and interactive exploration of the human anatomy.

  • 41.
    Jennergren, Johan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Storängen Söderköping- en visualisering av blivande ägarlägenheter på Storängen i Söderköping2012Independent thesis Basic level (university diploma), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    På Storängen i Söderköping bygger Bygg GG i Norrköping i samarbete med G Gunnarsons Fastighets AB ett hus innehållande 14 ägarlägenheter. Då försäljningen av lägenheterna startade innan huset var färdigt bestod den största delen av säljunderlaget av ritningar och skisser.

    Syftet med examensarbetet var att utföra en visualisering av det blivande husets yttre i form av en digital 3d-modell samt att visa hur några av de blivande lägenheterna skulle komma att se ut. Då många av lägenheterna i huset liknar varandra togs beslutet att visualisera tre av husets lägenheter.

    Rapporten beskriver hur arbetet med att ta fram visualiseringen genomförts. Den ger även en inblick i visualiseringsprocessen samt de programvaror som använts för projektet.

    Projektet kan delas in i två delar. En exteriör del och en interiör del.

    I den exteriöra delen byggdes en 3d-modell av huset i 3d-programmet Google SketchUp som är ett lättanvänt program för att skapa digitala skisser och 3d-modeller. Modellen som kopplades samman med programmet Google Earth som är en ”digital jordglob” visar hur husets yttre skulle komma att se ut.

    Till den interiöra delen, som var projektets huvuddel byggdes en ny modell i samma program som den tidigare modellen. Modellen exporterades till 3d-programmet Autodesk 3ds Max där texturering, ljussättning och rendering för tre av de fjorton lägenheterna i huset genomfördes. 3ds Max som är ett mer avancerat program än SketchUp, ger användaren möjligheten att göra verklighetstrogna visualiseringar.

    Från 3ds Max renderades totalt 36 olika bilder fram från de tre lägenheterna. Ett urval av bilderna användes senare som säljunderlag för lägenheterna.

  • 42.
    Daungklang, Phummipat
    et al.
    Linköping University, Department of Science and Technology.
    Mahavongvun, Amnauy
    Linköping University, Department of Science and Technology.
    Create a process for manually editing Rapid 3D Mapping Datasets2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In an existing process, Rapid 3D Mapping datasets are automatically generated and converted to a format suitable for simulators and mission support systems. However, this high level automation does not allow manual error fixes and the addition of important features to the map data. The aim of this thesis is to create a process that allows the editing of a number of R3DM tiles with an existing 3D modeling tool and, after editing, to propagate the changes to the lower levels of detail in the data. Two solutions for the propagation, a standard solution and an alternative, are presented in this thesis. The motivation behind the alternative solution is to keep the original geometry of the R3DM data to retain the good rendering performance which those data sets permit. To achieve this the new model will be added to the R3DM data at only the highest level of detail, and this model is then simplified before propagation to the lower levels of detail. The resulting procedure to fix errors and add new important features is very effective, and reduces the time required for users to edit the many levels of the R3DM data.

  • 43.
    Liang, Liu
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Test Immersion in DomeTheater using Tracking device2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Head tracking is an important way to interact with virtual objects in virtual world. The viewercan move or rotate his head to observe the 3D scene in dierent view. Normally head tracking isused in a cave or just on a at screen.Dome theater has a half sphere screen with multiple projectors together for showing the wholescene onto the big screen. The dome screen could give the viewer a very strong immersion feelingwhen head tracking inside dome theater and that is why we want to implement head tracking indome theater. The half sphere dome screen is so big that multiple projectors should be used forshooting the whole scene onto the big screen. Hence a cluster system is used for manipulating allthe projectors working smoothly. The display system of dome theater has no place for the headtracking part.This thesis tries to introduce a method to do head tracking in dome theater. The mainproblem is how to add head tracking in the display system in dome theater. Frame buer object(FBO) is used as the solution for this problem. The viewer's viewing frustum is created in framebuer object in order to render the 3D scene depending on the viewer's head position. The FBOtexture will then be attached onto a 3D sphere which simulates the dome sphere in virtual world.Since the viewing frustum is always created depending on the viewer's head position, the FBOtextures on the 3D sphere always can represent the 3D scene rendered depending on the viewer'shead position. Using the projectors to shoot the 3D scenes which is the 3D sphere attached by theFBO textures onto the dome screen. That is the main part of how to implement head tracking indome theater.This thesis forcus on rendering the 3D scene onto the dome screen depending on the viewer'shead position. The tracking device controlling part is out of this thesis's scope. VR Juggler (VRJ) is used as the framework in this project. Viewer's position setting and cluster setting are allsetted in the conguration file.

  • 44.
    Mekritthikrai, Kanit
    Linköping University, Department of Science and Technology.
    High Resolution Planet Rendering2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Planet rendering plays an important role in universe visualization and geographic visualization. The recent tools and methods allow better data acquisition, usually with very high resolution. However in computer graphics, there is always the limitation on the resolution of geometry and texture due to numerical imprecision. Not many applications can handle high resolution data effectively.

    This thesis introduces, Implicit Surface Scene, a level of detail scene management inspired by dynamic coordinate system and SCALEGRAPH™ which change over time depending on the current camera position relative to the planet surface. Our method is integrated into Uniview and allows Uniview to render high resolution planet geometry with dynamic texture composition and with a surface positioning system that does not suffer from precision issue.

  • 45.
    Birgersson, Elin
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry.
    Gene identification in the encystation pathway of the Dictyostelid Polysphondylium pallidum2011Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Encystation of unicellular organisms is of considerable medical relevance since cysts are encapsulated byresilient cell walls, rendering them resistant to biocides and immune clearance. This survival strategymakes it complicated to produce effective treatment of diseases caused by many protozoan pathogens,e.g. species of Acanthamoeba which causes fatal granulomatous amebic encephalitis (GAE) and keratitis.Due to genetic limitations in most protists, the machinery of encystation is so far little understood.However, the signalling pathways can be investigated in the non-pathogenic social amoebas, Dictyostelia.In this master’s project, five genes in Polysphondylium pallidum were investigated, which might beinvolved in encystation. Research has demonstrated a relationship between encystation and the cyclicadenosine monophosphate (cAMP) signalling pathways in Dictyostelia spore formation. This indicates thatcysts are ancestral to spores, and hence are the sporulation genes: pkaC, yakA, regA, cudA and srfAselected for this study. The genes were individually knocked-out by a standard homologous recombinationapproach and the genes’ contribution to encystation was determined. Five knock-out constructs werecompleted and a preliminary analysis of the role of the intracellular cAMP phosphodiesterase RegA inPolysphondylium pallidum encystation process was performed.

  • 46.
    Eilertsen, Gabriel
    Linköping University, Department of Science and Technology, Media and Information Technology.
    High-resolution simulation and rendering of gaseous phenomena from low-resolution data2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Numerical simulations are often used in computer graphics to capture the effects of natural phenomena such as fire, water and smoke. However, simulating large-scale events in this way, with the details needed for feature film, poses serious problems. Grid-based simulations at resolutions sufficient to incorporate small-scale details would be costly and use large amounts of memory, and likewise for particle based techniques.

    To overcome these problems, a new framework for simulation and rendering of gaseous phenomena is presented in this thesis. It makes use of a combination of different existing concepts for such phenomena to resolve many of the issues in using them separately, and the result is a potent method for high-detailed simulation and rendering at low cost.

    The developed method utilizes a slice refinement technique, where a coarse particle input is transformed into a set of two-dimensional view-aligned slices, which are simulated at high resolution. These slices are subsequently used in a rendering framework accounting for light scattering behaviors in participating media to achieve a final highly detailed volume rendering outcome. However,the transformations from three to two dimensions and back easily introduces visible artifacts, so a number of techniques have been considered to overcome these problems, where e.g. a turbulence function is used in the final volume density function to break up possible interpolation artifacts.

  • 47.
    Lundell, Fredrik
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Out-of-Core Multi-Resolution Volume Rendering of Large Data Sets2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A modality device can today capture high resolution volumetric data sets and as the data resolutions increase so does the challenges of processing volumetric data through a visualization pipeline. Standard volume rendering pipelines often use a graphic processing unit (GPU) to accelerate rendering performance by taking beneficial use of the parallel architecture on such devices. Unfortunately, graphics cards have limited amounts of video memory (VRAM), causing a bottleneck in a standard pipeline. Multi-resolution techniques can be used to efficiently modify the rendering pipeline, allowing a sub-domain within the volume to be represented at different resolutions. The active resolution distribution is temporarily stored on the VRAM for rendering and the inactive parts are stored on secondary memory layers such as the system RAM or on disk. The active resolution set can be optimized to produce high quality renders while minimizing the amount of storage required. This is done by using a dynamic compression scheme which optimize the visual quality by evaluating user-input data. The optimized resolution of each sub-domain is then, on demand, streamed to the VRAM from secondary memory layers. Rendering a multi-resolution data set requires some extra care between boundaries of sub-domains. To avoid artifacts, an intrablock interpolation (II) sampling scheme capable of creating smooth transitions between sub-domains at arbitrary resolutions can be used. The result is a highly optimized rendering pipeline complemented with a preprocessing pipeline together capable of rendering large volumetric data sets in real-time.

  • 48.
    Fries, Jakob
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering.
    Johansson, Simon
    Linköping University, Department of Electrical Engineering, Computer Engineering.
    A Modular 3D Graphics Accelerator for FPGA2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A modular and area-efficient 3D graphics accelerator for tile based rendering in FPGA systems has been designed and implemented. The accelerator supports a subset of OpenGL, with features such as mipmapping, multitexturing and blending. The accelerator consists of a software component for projection and clipping of triangles, as well as a hardware component for rasterization, coloring and video output. Trade-offs made between area, performance and functionality have been described and justified. In order to evaluate the functionality and performance of the accelerator, it has been tested with two different applications.

  • 49.
    Bengtsson, Morgan
    Linköping University, Department of Science and Technology.
    Real time global illumination using the GPU2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Global illumination is an important factor when striving for photo realism in computergraphics. This thesis describes why this is the case, and why global illumination is considered acomplex problem to solve. The problem becomes even more demanding when considering realtime purposes. Resent research has proven it possible to produce global illumination in realtime. Therefore the subject of this thesis is to compare and evaluate a number of those methods.

    An implementation is presented based on the Imperfect shadow maps method, which per se isbased on instant radiosity and reflective shadow maps. The implementation is able to renderplausible global illumination effects in real time, for fully dynamic scenes.

    With conclusions that while it demonstrably is possible to provide believable global illum-ination in real time, it is not without shortcomings. In every case approximations or restrictionshas to be done to some extent, sometimes leading to wrong results. Though in most cases, notvisually unpleasing by a great deal.

    The final conclusion is that global illumination is possible on current hardware, with believablequality and good speed. Showing great potential for future implementations on next generationof hardware.

  • 50.
    Hedberg, Vilhelm
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Evaluation of Hair Modeling, Simulation and Rendering Algorithms for a VFX Hair Modeling System2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Creating realistic virtual hair consists of several major areas: creating the geometry, moving the hair strands realistically and rendering the hair. In this thesis, a background survey covering each one of these areas is given. A node-based, procedural hair system is presented, which utilizes the capabilities of modern GPUs. The hair system is implemented as a plugin for Autodesk Maya, and a user interface is developed to allow the user to control the various parameters. A number of nodes are developed to create effects such as clumping, noise and frizz. The proposed system can easily handle a variety of hairstyles, and pre-renders the result in real-time using a local shading model.

     

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