Thesis in Computer Sciences at the Marne-La-Vallée University

CIFRE-French Ministry of Research Training in Industry Convention with Direction des Constructions Navales (DCN Ingénierie) in Toulon (Var), presented 20/01/1999

Title :“Rendu réaliste et surfaces complexes : application à la simulation du milieu maritime.”
Research Advisor :Pr. Didier Arquès
Committee :

Pr. René CAUBET, Université de Toulouse

Pr. Bernard PEROCHE, Université de Saint-Étienne

M. Paul GENTRIC, Ingénieur DCN

Pr. Kadi BOUATOUCH, Université de Rennes 1

Dr. Sylvain MICHELIN, Université de Marne-la-Vallée

Pr. Dominique PERRIN, Université de Marne-la-Vallée

Pr. Claude SECROUN , Université de Reims

Abstract :

The works presented in this thesis concern the realistic rendering and the modelisation of complex surfaces including an application to the image synthesis of maritime scenes realised in collaboration with DCN Ingénierie. We study two important problems of image synthesis: simulating precisely the exchanges of energy that appear in presence of specularly reflective surfaces and participating media, and modelling the complex surfaces as for example the surface of the sea.

The first part presents a state of the art on the models used in image synthesis. We propose here, the laws and physical models which describe the emission of energy and the interactions between light and objects. Then we present the main illumination models and more precisely the algorithm called radiosity, which use these laws to generate realistic synthesised images. We conclude this first part with a presentation of the main models which permit the description of the surface of objets and particularly the surface of the sea.

The second part of this document shows the results of our research works. We propose a new extension of the radiosity model that allows to treat simultaneously the specular reflections and participating media, and a method - using words - that permits to identify and classify the different exchanges appearing in a scene. We present then a new model of representation of complex surfaces based on the definition of atlas of discoid and we finally rewrite the model of radiosity to integrate this new model of representation.

The third part, more practical, proposes the adaptation of the previous algorithms to the simulation of maritime scenes for visible and infrared radiations.

The last part (annexes) contains a presentation of the software developed during this thesis.

Keywords :

image synthesis, illumination models, radiosity, representation of complex surfaces.