Paper internal structure defines many of its final properties. Thus structure characterisation is a useful tool for papermakers. However, there are no user-friendly, fast and cost-effective methods that provide paper structure. During this PhD, a system based on full-field optical coherence tomography (OCT) with a thermal light source was developed to study paper. This non-destructive method comes from biomedical field. Spatial resolution of the setup is about one micrometer in the three directions. Images of inside structure of paper sheets were acquired. Results and penetration depth depend strongly on the kind of paper and on its optical properties. The fundamental limitation of this technique is multiple scattering in paper. OCT offers yet many potential applications in paper industry and experiments prove that improvements would be possible to increase penetration depth.
Développement et application de la tomographie par cohérence optique plein champ pour l'étude du matériau papier