Bøger af Christian Bouville

Rendering photorealistic images is a costly process which can take up to several days in the case of high quality images. In most cases, the task of sampling the incident radiance function to evaluate the illumination integral is responsible for an important share of the computation time. Therefore, to reach acceptable rendering times, the illumination integral must be evaluated using a limited set of samples. Such a restriction raises the question of how to obtain the most accurate approximation possible with such a limited set of samples. One must thus ensure that sampling produces the highest amount of information possible by carefully placing and weighting the limited set of samples. Furthermore, the integral evaluation should take into account not only the information brought by sampling but also possible information available prior to sampling, such as the integrand smoothness. This idea of sparse information and the need to fully exploit the little information available is present throughout this book. The presented methods correspond to the state-of-the-art solutions in computer graphics, and take into account information which had so far been underexploited (or even neglected) by the previous approaches. The intended audiences are Ph.D. students and researchers in the field of realistic image synthesis or global illumination algorithms, or any person with a solid background in graphics and numerical techniques.

The goal of this book is to present the most advanced research works in realistic computer generated images. It is made up of the papers presented during a Eurographics workshop that has been held in Rennes (France) on June 1990. Although realism in computer graphics has existed for many years, we have considered that two research directions can now clearly be identified. One makes use of empirical methods to efficiently create images that look real. As opposed to this approach, the other orientation makes use of physics to produce images that are exact representations of the real world (at the expense of additional processing time), hence the term photosimulation which indeed was the subject of this book. The objectives of this workshop were to assemble experts from physics and computer graphics in order to contribute to the introduction of physics-based approaches in the field of computer generated images. The fact that this workshop was the first entirely devoted to this topic was a bet and fortunately it turned out that it was a success. The contents of this book is organized in five chapters: Efficient Ray Tracing Meth- ods, Theory of Global Illumination Models, Photometric Algorithms, Form-Factor Cal- culations and Physics-Based Methods.