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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....
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Colour reproduction accuracy of stochastic spectral sampling: an experimental evaluation.
Hencz, Attila ; Wilkie, Alexander (advisor) ; Křivánek, Jaroslav (referee)
Title: Colour reproduction accuracy of stochastic spectral sampling: an experi- mental evaluation Author: Bc. Attila Hencz �attila.hencz@matfyz.cz� Department: Department of Software and Computer Science Education Supervisor: doc. Alexander Wilkie, Dr. �wilkie@cgg.mff.cuni.cz�, Department of Software and Computer Science Education Abstract: We investigate the colorimetric accuracy of stochastic sampling in the wavelength domain for realistic rendering purposes. In particular, we consider the impact of three specific design choices in a rendering system on the accuracy of the overall result: how exactly spectral samples are splatted into the final result spectrum, how many spectral channels one uses in the result images, and the impact of Hero Wavelength Spectral Sampling (HWSS) compared to the stand- ard monochrome technique. We provide experimental results, comparisons and evaluation of sampling high-resolution spectra that originate from measurements of real paint samples found in colour atlases, and normed light sources defined by the CIE. The latter include both smooth and spiky spectra, so the used com- bination of reflectances and light spectra provides a representative body of input values that allows to draw conclusions that are relevant for practical rendering work. Keywords: physically based image...
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Colour reproduction accuracy of stochastic spectral sampling: an experimental evaluation.
Hencz, Attila ; Wilkie, Alexander (advisor) ; Křivánek, Jaroslav (referee)
Title: Colour reproduction accuracy of stochastic spectral sampling: an experi- mental evaluation Author: Bc. Attila Hencz �attila.hencz@matfyz.cz� Department: Department of Software and Computer Science Education Supervisor: doc. Alexander Wilkie, Dr. �wilkie@cgg.mff.cuni.cz�, Department of Software and Computer Science Education Abstract: We investigate the colorimetric accuracy of stochastic sampling in the wavelength domain for realistic rendering purposes. In particular, we consider the impact of three specific design choices in a rendering system on the accuracy of the overall result: how exactly spectral samples are splatted into the final result spectrum, how many spectral channels one uses in the result images, and the impact of Hero Wavelength Spectral Sampling (HWSS) compared to the stand- ard monochrome technique. We provide experimental results, comparisons and evaluation of sampling high-resolution spectra that originate from measurements of real paint samples found in colour atlases, and normed light sources defined by the CIE. The latter include both smooth and spiky spectra, so the used com- bination of reflectances and light spectra provides a representative body of input values that allows to draw conclusions that are relevant for practical rendering work. Keywords: physically based image...
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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....
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