Interactive Relighting and Remodelling
of Real Scenes for Augmented Reality

Céline Loscos

Thesis in Computer Science, carried on in iMAGIS-GRAVIR/IMAG-INRIA.
Defended on the 20th of December 1999, in Grenoble, in France.

Abtract

Computer augmented reality is a rapidly emerging field allowing users to mix virtual and real worlds. In this thesis, we concentrate on interactive relighting, i.e. virtually modifying lighting properties, and remodelling of real interior scenes, with realistic mixed lighting effects. We have developed two new methods to achieve these objectives. For the two methods, we use non exhaustive input data to estimate radiometric properties of real scenes. In the first approach, we use a simple textured model of the real scene. We first remove original lighting effects from the textures using a new algorithm based on radiosity equations. During the interactive modification step (which achieve an update rate of 3 images per second), lighting effects are simulated by incremental algorithms, and the display is done using the graphics hardware. We developed a second method for which the real scene is known from photographs taken under several different but controlled lighting conditions. Diffuse reflectances are computed pixel per pixel for the input image. New lighting conditions are then simulated using ray tracing for direct illumination, and optimised hierarchical radiosity for indirect illumination. Finally, we propose a new photometric calibration method, for non professional cameras, and we present algorithms which improve the quality of the reflectance estimate for both methods.

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Document (PDF in french)

Complete document:
Complete document with low-resolution images (2.2M)
Complete document with high-resolution images (6.1M)

Document in several parts:
Résumé (8K)
Titre, Remerciements, Tables des matières et des figures (51K)
Chapitre 1 : Introduction (176K)
Chapitre 2 : Etat de l'art (935K)
Chapitre 3 : Problèmes d'acquisition (1.5M)
Chapitre 4 : Modification des propriétés d'éclairage d'une scène réelle à partir d'un seul éclairage connu (960K)
Chapitre 5 : Modification des propriétés d'une scène réelle connue sous différents éclairages (1.6M)
Chapitre 6 : Calibrage photométrique (1.3M)
Chapitre 7 : Comparaisons et améliorations (41K)
Chapitre 8 : Conclusion (37K)
Annexes et Références (170K)

Main publications on my thesis work