Frank Suykens Katholieke Universiteit Leuven

Contact: Computer Graphics Research Group

Ph.D. Thesis, Katholieke Universiteit Leuven, 258 + xiii p

Abstract

Computer-generated realistic images are being used increasingly in applications such as architecture, lighting design and visual effects in the movie industry. Therefore, realistic image synthesis, the subject of this dissertation, has remained one of the most important research areas in computer graphics for many years.

Realistic image synthesis takes as input a description of a three-dimensional scene and a virtual camera looking upon that scene. By simulating the light transport, the intensity of each pixel in the image as seen by the camera can be computed. Light transport can be described by an integral equation, often called the rendering equation. Algorithms that compute all possible interreflections of light in the scene and thus provide a full solution to the rendering equation, are called global illumination algorithms. Such algorithms produce images that are virtually indistinguishable from real photographs, but unfortunately they are slow.

In this dissertation we present several new techniques to construct more robust and more efficient global illumination algorithms. Our work focuses on Monte Carlo algorithms and multi-pass methods. Monte Carlo algorithms statistically estimate integrals and are very well suited for solving transport problems. Multi-pass methods combine several rendering algorithms into a single method. A good multi-pass configuration will preserve the strengths of each individual component, while avoiding its weaknesses.

First, new techniques for designing better multi-pass methods are presented, including weighted multi-pass methods that weight the contributions of different algorithms automatically in a provably good manner. Second, path differentials are introduced. They allow to augment light transport paths with neighborhood information which is useful in many global illumination algorithms. Finally a technique is presented to reduce the memory requirements and to control the error in photon mapping, an efficient and popular global illumination algorithm.

All these techniques result in more robust and efficient global illumination algorithms and contribute to the increasing use of these algorithms in computer graphics applications.

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Downloads

My dissertation is available in different formats:

• PDF, A4, normal line spacing: suykens_a4.pdf  (16 MB, 175 pages)
• PDF, A4, double line spacing for easier reading: suykens_dbl.pdf (16 MB, 230 pages)
• Postscript, A4, two pages per page to save trees: suykens_2up.ps.gz (23 MB, gzipped, 120 A4 pages)

NB: This is the original printed version (which is 16cm x 24cm) but formatted as two pages on a single
A4 (I hacked the postscript in the file, so it does not work with page numbering in Ghostview etc.)

There is also a dutch summary available (36 pages) in pdf format: suykens_nl.pdf
 

Table of Contents

Following is the table of contents. Each chapter is available as a separate PDF file in double line spacing format.

• Title & Preface (26k)
• Table of Contents (and notations) (64k)
• Chapter 1 Introduction (25k)
• Chapter 2 A mathematical model for light transport (80k)
• Chapter 3 Monte Carlo integration (2.3M)
• Chapter 4 Multi-pass methods (320k)
• Chapter 5 Regular expression based path evaluation (2.5M) 
  This is mainly my WSCG 1999 paper.
• Chapter 6 Weighted Multi-Pass Methods (5.4M)
  Mainly my EG 1999 paper (with the theory slightly generalized)
• Chapter 7 Path differentials (2.5M)
  Extended version of my EGWR 2001 paper (more general and extended theory, some use of second order derivatives, ...)
• Chapter 8 Photon mapping (860k)
  Overview and analysis of photon mapping
• Chapter 9 Density control for photon maps (2.1M)
  Most of the stuff from my EGWR 2000 paper and the visual importance part of the SIGGRAPH 2001/2002 photon mapping course notes,
  plus a thorough analysis of the photon power redistribution and an improved redistribution.
• Chapter 10 Conclusion (20k)
• Bibliography (37k)

Presentation

The Powerpoint presentation that I used for my defense is also online: phdsuykens.ppt (11M). If you use them, please do acknowledge where they came from.

Photos

There are a few photos online of the public defense. Not for the faint of heart ;-)

Links

• Lirias