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Rendering Planetary Atmospheres in Real-Time
Elek, Oskár ; Kmoch, Petr (advisor) ; Maršálek, Lukáš (referee)
In the field of photorealistic rendering of physical phenomena, the rendering of atmospheric light scattering takes a very important place. Realtime rendering of sky and atmosphere in general is essential for all outdoor computer games, various simulators, virtual worlds or even for animated movies. It is a very difficult task, but thanks to the advancement of dedicated graphics hardware we can reach it today. In my thesis I present an accurate and fast method for real-time rendering of planetary atmospheres. This is achieved by precomputing complex single-scattering equations into a set of lookup tables. The correct atmospheric colour values are then fetched from these in the fragment shader. The presented method is then implemented in a program that is capable of rendering realistic atmosphere in hundreds of FPS.
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Physically-based Cloud Rendering on GPU
Elek, Oskár ; Wilkie, Alexander (advisor) ; Křivánek, Jaroslav (referee)
The rendering of participating media is an interesting and important problem without a simple solution. Yet even among the wide variety of participating media the clouds stand out as an especially difficult case, because of their properties that make their simulation even harder. The work presented in this thesis attempts to provide a solution to this problem, and moreover, to make the proposed method to work in interactive rendering speeds. The main design criteria in designing this method were its physical plausibility and maximal utilization of specific cloud properties which would help to balance the complex nature of clouds. As a result the proposed method builds on the well known photon mapping algorithm, but modifies it in several ways to obtain interactive and temporarily coherent results. This is further helped by designing the method in such a way which allows its implementation on contemporary GPUs, taking advantage of their massively parallel sheer computational power. We implement a prototype of the method in an application that renders a single realistic cloud in interactive framerates, and discuss possible extensions of the proposed technique that would allow its use in various practical industrial applications.
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Real Time Visualization of Chaotic Functions
Teichmann, Antonín ; Elek, Oskár (advisor) ; Wilkie, Alexander (referee)
Fractals are a fundamental natural structure that has fascinated the sci- entific community for a long time. To allow for better understanding of fractals, visualization techniques can be used. The focus of this thesis is real-time rendering of fractals that are similar to the Mandelbrot set or the Newton fractal. Detailed exploration of these fractals is complicated due to their recursive-manner which leads to the fact that rendering them is com- putationally demanding. Existing solutions do not work in real-time or have low visual quality. We want to change that and allow high-quality real- time rendering. During our analysis of the problem, we generalize fractals to chaotic functions. To achieve high-quality rendering with low overhead, we introduce a method for adaptive super-sampling of chaotic functions. To achieve real-time performance, we show how to use sample reuse, foveated rendering, and other techniques. We implement a parallel, GPU-based, high- quality renderer that runs in real-time and produces visually-attractive views of given fractals. The program can visualize any given chaotic function. This way, we open the realm of real-time visualization of chaotic functions to the public and lay a basis for future research. 1
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Efficient GPU path tracing in solid volumetric media
Forti, Federico ; Elek, Oskár (advisor) ; Goel, Anisha (referee)
Realistic Image synthesis, usually, requires long computations and the simulation of the light interacting with a virtual scene. One of the most computationally intensive simulation in this area is the visualization of solid participating media. This media can describe many different types of object with the same physical parameters (e.g. marble, air, fire, skin, wax ...). Simulating the light interacting with it requires the computation of many independent photons interactions inside the medium. However, those interactions can be computed in parallel, using the power of modern Graphic Processor Unit, or GPU, computing. This work present an overview over different methodologies, that can affect the performance of this type of simulations on the GPU. Different existing ideas are analyzed, compared and modified with the scope of speeding up the computation respect to the classic CPU implementation. 1
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Image Denoising Using Weighted Local Regression
Šťasta, Jakub ; Křivánek, Jaroslav (advisor) ; Elek, Oskár (referee)
The problem of accurately simulating light transport using Monte Carlo integration can be very difficult. In particular, scenes with complex illumination effects or complex materials can cause a scene to converge very slowly and demand a lot of computational time. To overcome this problem, image denoising algorithms have become popular in recent years. In this work we first review known approaches to denoising and adaptive rendering. We implement one of the promising algorithm by Moon et al. [2014] in a commercial rendering system Corona Standalone Renderer, evaluate its performance, strengths and weaknesses on 14 test scenes. These include difficult to denoise and converge rendering effects such as fine sub-pixel geometry, participating media, extreme depth of field of highlights, motion blur, and others. We propose corrections which make the algorithm more stable and robust. We show that it is possible to denoise renderings with Linear Weighted Regression only using a CPU. However, still even after our propositions, it is not possible to filter scenes in a consistent manner without over-blurring or not filtering where desired.
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Real-Time Light Transport in Analytically Integrable Participating Media
Iser, Tomáš ; Elek, Oskár (advisor) ; Horáček, Jan (referee)
The focus of this thesis is the real-time rendering of participating media, such as fog. This is an important problem, because such media significantly influence the appearance of the rendered scene. It is also a challenging one, because its physically correct solution involves a costly simulation of a very large number of light-particle interactions, especially when considering multiple scattering. The existing real-time approaches are mostly based on empirical or single-scattering approximations, or only consider homogeneous media. This work briefly examines the existing solutions and then presents an improved method for real-time multi- ple scattering in quasi-heterogeneous media. We use analytically integrable den- sity functions and efficient MIP map filtering with several techniques to minimize the inherent visual artifacts. The solution has been implemented and evaluated in a combined CPU/GPU prototype application. The resulting highly-parallel method achieves good visual fidelity and has a stable computation time of only a few milliseconds per frame.
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GPU Acceleration of Advanced Image Denoising
Honzátko, David ; Kruliš, Martin (advisor) ; Elek, Oskár (referee)
BM3D (Block-Matching and 3D Filtering) is one of the state-of-art image denoising methods. Efficient implementations of this method exist for the CPU; however, these implementations are time demanding. On common desktop computers, denoising of high-resolution images can reach several minutes. The main objective of this thesis is to design an implementation of the BM3D method that utilize raw computational power of the GPU. GPU offers significantly more computational cores than the CPU; however, due to the specific execution and memory model, algorithms for the GPU are very different from algorithms for the CPU. Therefore, this thesis presents both: the basic aspects of the GPU computing and the BM3D method itself. Last but not least, the final implementation is empirically evaluated against the existing implementations by a set of performance tests. Powered by TCPDF (www.tcpdf.org)
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Physically-based Cloud Rendering on GPU
Elek, Oskár ; Wilkie, Alexander (advisor) ; Křivánek, Jaroslav (referee)
The rendering of participating media is an interesting and important problem without a simple solution. Yet even among the wide variety of participating media the clouds stand out as an especially difficult case, because of their properties that make their simulation even harder. The work presented in this thesis attempts to provide a solution to this problem, and moreover, to make the proposed method to work in interactive rendering speeds. The main design criteria in designing this method were its physical plausibility and maximal utilization of specific cloud properties which would help to balance the complex nature of clouds. As a result the proposed method builds on the well known photon mapping algorithm, but modifies it in several ways to obtain interactive and temporarily coherent results. This is further helped by designing the method in such a way which allows its implementation on contemporary GPUs, taking advantage of their massively parallel sheer computational power. We implement a prototype of the method in an application that renders a single realistic cloud in interactive framerates, and discuss possible extensions of the proposed technique that would allow its use in various practical industrial applications.
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Rendering Planetary Atmospheres in Real-Time
Elek, Oskár ; Maršálek, Lukáš (referee) ; Kmoch, Petr (advisor)
In the field of photorealistic rendering of physical phenomena, the rendering of atmospheric light scattering takes a very important place. Realtime rendering of sky and atmosphere in general is essential for all outdoor computer games, various simulators, virtual worlds or even for animated movies. It is a very difficult task, but thanks to the advancement of dedicated graphics hardware we can reach it today. In my thesis I present an accurate and fast method for real-time rendering of planetary atmospheres. This is achieved by precomputing complex single-scattering equations into a set of lookup tables. The correct atmospheric colour values are then fetched from these in the fragment shader. The presented method is then implemented in a program that is capable of rendering realistic atmosphere in hundreds of FPS.
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