Global illumination on point-based models
Nicolas Bonneel, Mathias Paulin, Gael Guennebaud,
for my Master 2 internship and my INSA's 5th year internship, at IRIT, France (Feb.-June 2006)
Download pdf (french) !
Download ppt (french) !
| The Global illumination purpose is to compute multiple reflections of light in a scene so as to get a certain realism when rendering. Considering some restrictions and a long precomputation time, some algorithms can render global illumination in real time. Our method avoids the restriction of low frequency materials (not very shiny) thanks to the lighting representation as a sum of Gaussian lobes, and allows to render static scenes in real time, with a moving viewer. The simulation of global illumination is done by a photon tracing step, followed by a lobe parameters fitting which is done by an Expectation-Maximization algorithm. A real-time evaluation of the rendering equation is achieved by approximating the convolution of Gaussian lobes. Keywords : Image synthesis, Global illumination, BRDF, Expectation-Maximization |
| L'éclairage global consiste à calculer les multiples réflexions de la lumière dans une scène afin d'obtenir un certain réalisme lors de son rendu. Selon certaines restrictions et un précalcul long, des algorithmes permettent un rendu temps réel de l'éclairage global. Nous nous affranchissons ici de la restriction des matériaux basses fréquences (peu brillants) grâce à la modélisation de l'éclairage sous forme d'une somme de lobes Gaussiens, afin d'effectuer le rendu temps réel de scènes statiques avec un observateur dynamique. La simulation de l'éclairage est calculée par un lancer de photons, et l'ajustement des paramètres des lobes est effectué par un algorithme d'Expectation-Maximization. Une expression de l'équation du rendu est obtenue par une approximation de la convolution de lobes Gaussiens. Mots clefs : Synthèse d'images, Éclairage global, BRDF, Expectation-Maximization |
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divx, 10.1 MB Direct + Indirect lighting (direct lighting computed with a gaussian lobe too...) Specular David, Diffuse Cornell Box Show global Tone Mapping problems due to black environment Show Tone Mapping perceptual effect (night vision) at the end. |
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divx, 8.18 MB Direct + Indirect lighting (direct lighting computed with a gaussian lobe too...) Specular David, Diffuse Cornell Box 1st second shows a reference, then the reconstruction Show Tone Mapping perceptual effect (night vision) at the end. |
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divx 10.5 MB Only indirect lighting first, then Direct + Indirect lighting (direct lighting computed with a gaussian lobe too...) Specular David, Diffuse Cornell Box No Tone Mapping |