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Efficient rendering of caustics with streamed photon mapping

Guzek K., Napieralski P.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 3

361--368

EN

In this paper, we present the streamed photon mapping method for enhancing the rendering of caustics. In order to achieve a realistic caustic effect, global illumination methods require additional data, which are gathered by creating a caustic map or increasing the number of samples used for rendering. Our method employs a stream of photons with a varying luminance level depending on the material properties of the surface. The application of a concentrated photon stream provides the ability to render caustics effectively without increasing the number of photons in a photon map. Such an approach increases visibility of results, while also allowing for faster computations.

2

Rendering participating media with streamed photon mapping

Guzek K., Napieralski P.

Journal of Applied Computer Science

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2016

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Vol. 24, nr 1

7--15

EN

The research on Streamed Photon Mapping method has shown its efficiency and potential. Significant caustic effects without an additional caustic map are its undeniable advantage. The method assumed that light spreads in a vacuum; however, such approach excluded the visualization of such phenomena as fog, smoke, or clouds. This paper presents a modification of the basic method of rendering with the help of photon streams, taking into account the simulation of light in dense mediums. The specifics of stream structure and the applied solutions allow to eliminate multiple assessment of the same photons as it occurred in the case of standard Volumetric Photon Mapping.

3

Streamed Photon Mapping

Guzek K., Napieralski P.

Metody Informatyki Stosowanej

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2011

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nr 4

67-74

EN

In this paper, we present a new solution for Global Illumination – an extended photon mapping algorithm. Our technique replaces samples technique in traditional photon mapping as well as the manner of photon map construction. Our approach avoids emitting unneeded photons and decreased computation time. The proposed approach allows one to reduce the number of comparisons when searching for neighbouring photons in order to calculate the final colour of the pixel.

4

Measurement of noise in the Monte Carlo point sampling method

Guzek K., Napieralski P.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2011

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Vol. 59, nr 1

15-19

EN

This paper gives a concise overview of the techniques we have used to find out the degree of measuring the quality of rendered images and a level of noise in particular. First part of the paper presents designed and conducted psychophysical experiment involving human subjective judgment. Then, two of the existing numerical image comparison methods are considered in the context of assessing the level of noise produced by global illuminations algorithms. The results of the participants’ subjective responses are correlated with the data obtained from objective mathematical metrics. The main goal of research was to determine the objective and perceptual measure of quality for images with fixed sampling strategy. The results will help to establish the measures of identifying the human perception in the assessment of images generated with global illumination algorithms.

5

Variance and variation reduction technique in the quasi-Monte Carlo global illumination algorithm

Kozankiewicz P.

Machine Graphics and Vision

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2000

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Vol. 9, No. 1/2

289-296

EN

The accuracy of the Monte Carlo and quasi-Monte Carlo algoriths depends on variance and variation in the sense of Hardy-Krause of the integral. This paper contains an error estimation of the quasi-Monte Carlo algorithm for some discontinuous functions that appear in radiosity and global illumination computation. Also an algorith that transforms the integral to reduce variance and variation is presented. It takes advantage of the BRDF properties and it can be used with diffuse and non-diffuse environments.