National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Global exploration in Markov chain Monte Carlo methods for light transport simulation
Šik, Martin ; Křivánek, Jaroslav (advisor) ; Jakob, Wenzel (referee) ; Christensen, Per (referee)
Monte Carlo light transport simulation has become a de-facto standard tool for photorealistic rendering. However, the algorithms used by the current rendering systems are often ineffective, especially in scenes featuring light transport due to multiple highly glossy or specular interactions and complex visibility between the camera and light sources. It is therefore desirable to adopt more robust algorithms in practice. Light transport algorithms based on Markov chain Monte Carlo (MCMC) are known to be effective at sampling many different kinds of light transport paths even in the presence of complex visibility. However, the current MCMC algorithms often over-sample some of the paths while under-sampling or completely missing other paths. We attribute this behavior to insufficient global exploration of path space which leads to their unpredictable convergence and causes the occurrence of image artifacts. This in turn prohibits adoption of MCMC algorithms in practice. In this thesis we therefore focus on improving global exploration in MCMC algorithms for light transport simulation. First, we present a new MCMC algorithm that utilizes replica exchange to improve global exploration. To maximize efficiency of replica exchange we introduce tempering of the path space, which allows easier discovery of important...
GPU implementation of the irradiance and radiance caching algorithms
Bulant, Martin ; Křivánek, Jaroslav (advisor) ; Šik, Martin (referee)
The objective of this work is to create software implementing two algorithms for global ilumination computation. Iradiance and radiance caching should be implemented in CUDA framework on a graphics card (GPU). Parallel implementation on the GPU should improve algoritm speed compared to CPU implementation. The software will be written using an already done framework for global illumunation computation. That allows to focus on algorithm implementation only. This work should speed up testing of new or existing methods for global illumination computing, because saving and reusing of intermediate results can be used for other algorithms too. Powered by TCPDF (www.tcpdf.org)
Výpočetní fotografie ve světelném poli a aplikace na panoramatické snímky
Kučera, Jan ; Šroubek, Filip (advisor) ; Šik, Martin (referee)
The digital photography is still trying to catch-up with its analogous counterpart and recording light direction is one of the most recent area of interest. The first and still the only one light-field camera for consumers, the Lytro camera, has reached market in 2011. This work introduces the light-field theory and recording with special emphasis on illustrating the principles in 2D, gives an overview of current hardware and ongoing research in the area and analyses the Lytro camera itself, describing the closed file formats and protocols it uses so that further research can be conducted. An important contribution of the work is a .NET portable library for developers, supplemented by a file editor as well as an application for wireless communication with the camera based on the library. Finally, the theory is used to discuss implications for light-field registration and linear panoramas. Powered by TCPDF (www.tcpdf.org)
Generování vlasů interpolací
Šik, Martin
This thesis describes a procedural hair generator that is able to generate hair from just a few hairs, called hair guides, which are directly modeled by a 3d artist. The procedural hair generator is a part of Stubble project -- a tool for hair modeling in Autodesk Maya. The procedural hair generator can generate hair during rendering, thus avoiding storage of hair geometry in a scene file, which makes the rendering process very efficient. Furthermore, hair can be generated interactively and displayed by OpenGL during modeling in Maya. Generated hair geometry is mainly defined by interpolation from the mentioned hair guides; however it is also influenced by many hair properties. These properties can change hair geometry using noise functions, define hair color, width and more. To determine hair root positions on a given triangular mesh I use my own mesh sampling algorithm that generates random samples on a triangular mesh according to a density defined by a 2-dimensional texture. My sampling algorithm uses an innovative way of sampling from a discrete probability distribution, which can be used in other applications than mesh sampling.
GPU implementation of the irradiance and radiance caching algorithms
Bulant, Martin ; Křivánek, Jaroslav (advisor) ; Šik, Martin (referee)
The object of this work is to create software implementing two algorithms for global ilumination computing. Iradiance and radiance caching should be implemented in CUDA framework on graphics card (GPU). Parallel implementation on GPU should dramatically improve algoritm speed compared to CPU implementation. The software will be written using already done framework for global illumunation computation. That allow to focus to algorithm implementation only. This work should speed up testing of new or existing methods for global illumination computing, because saving and reusing of intermediate results can be used for other algorithms too. Powered by TCPDF (www.tcpdf.org)
Polarising Versions of Glossy BRDF Models
Bártová, Kristina ; Wilkie, Alexander (advisor) ; Šik, Martin (referee)
The goal of computer graphics is to precisely model the appearance of real objects. It includes of interactions of light with various materials. Polarisation is one of the fundamental properties of light. Incorporating polarisation parameter into an illumination model can significantly enhance the physical realism of rendered images in the case of scenes including multiple light bounces via specular surfaces, etc. However, recent rendering systems do not take polarisation into account because of complexity of such a solution. The key component for obtaining physically correct images are realistic, polarisation capable BRDF (Bidirectional Reflectance Distribution Function) models. Within this thesis, polarising versions of the following BRDF models were theoretically derived: Torrance Sparrow, He-Torrance-Sillion-Greenberg and Weidlich-Wilkie. For each of these models, Mueller matrices (the mathematical construct used to describe polarising surface reflectance) were systematically derived and their behaviour tested under various input parameters using Wolfram Mathematica. Derived polarising glossy BRDF models were further implemented using a rendering research system, ART (Advanced Rendering Toolkit). As far as we know, it is the very first usage of these BRDF models in a polarisation renderer....
Realtime library for procedural generation and rendering of terrains
Kahoun, Martin ; Horáček, Jan (advisor) ; Šik, Martin (referee)
Techniques for procedural generation of the graphics content have seen widespread use in multimedia over the past thirty years. It is still an active area of research with many applications in 3D modeling software, video games, and films. This thesis focuses on algorithmic generation of virtual terrains in real-time and their real-time visualization. We provide an overview of available approaches and present an extendable library for procedural terrain synthesis. Powered by TCPDF (www.tcpdf.org)
Generování vlasů interpolací
Šik, Martin ; Křivánek, Jaroslav (advisor) ; Kolomazník, Jan (referee)
This thesis describes a procedural hair generator that is able to generate hair from just a few hairs, called hair guides, which are directly modeled by a 3d artist. The procedural hair generator is a part of Stubble project -- a tool for hair modeling in Autodesk Maya. The procedural hair generator can generate hair during rendering, thus avoiding storage of hair geometry in a scene file, which makes the rendering process very efficient. Furthermore, hair can be generated interactively and displayed by OpenGL during modeling in Maya. Generated hair geometry is mainly defined by interpolation from the mentioned hair guides; however it is also influenced by many hair properties. These properties can change hair geometry using noise functions, define hair color, width and more. To determine hair root positions on a given triangular mesh I use my own mesh sampling algorithm that generates random samples on a triangular mesh according to a density defined by a 2-dimensional texture. My sampling algorithm uses an innovative way of sampling from a discrete probability distribution, which can be used in other applications than mesh sampling.
Particle Systems
Šik, Martin ; Kmoch, Petr (referee) ; Pelikán, Josef (advisor)
In the present work I concern myself with the development of Particle systems library independent on any concrete graphical library. Particle systems are used in various graphical applications to render interesting e ects (for example: fi re, waterfall, smoke, explosions, etc.) which are nearly impossible to be rendered the same way as other ordinary objects in scene. Given the fact that this is very complex theme I choose to concentrate mostly on interactions between particles that would be fast enough for online rendering. For possible hard to compute interactions I allow saving calculated properties of particles and afterwards their fast playback. Because many moderns processors have more than one core some calculations in my library can run parallel in more threads.
Legal aspects of network industries and natural monopolies
Šik, Martin ; Handrlica, Jakub (advisor) ; Eichlerová, Kateřina (referee)
1 Summary Key words: Natural monopoly, network industry, energy industry, regulation, liberalization, unbundling, third party access The present thesis sets out to explore the legal aspects of network industries and natural monopolies. It researches these aspects using the example of the energy sector (i.e. the power and gas industries), which is a typical example of a network industry. In terms of its geographical scope, the thesis focuses on the EU energy law and its specific application in the Czech Republic. The fundamental point of departure for the present thesis is a believe that energy law is closely intertwined with economic policy, and is appropriately interpreted only in the context of the concrete measures, tools, and concepts meant to reflect a nation's energy policy. The main driver of energy policy, and hence also of energy law, is a reform of the energy industry aiming at its liberalization. The key tools for its successful implementation are economic regulation, third party access, unbundling, and public administration by independent regulatory bodies. Firstly, the present thesis discusses the economic characteristics of network industries, that is most importantly the existence of a natural monopoly. The second part of the thesis outlines the background of liberalization and the related...

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6 ŠIK, Martin
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