09/07/2013 - 14H00 - Amphi Mauduit - ENSEM à Nancy Brabois

"Modèles de minimisation d'énergies discrètes pour la cartographie cystoscopique"
(Thèse Thomas WEIBEL)

Résumé :
ABSTRACT
The aim of this thesis is to facilitate bladder cancer diagnosis. The reference clinical examination
is cystoscopy, where an endoscope, inserted into the bladder, allows to visually explore
the organ's internal walls on a monitor. The main restriction is the small field of view (FOV)
of the instrument, which complicates lesion diagnosis, follow-up and treatment traceability. In
this thesis, we propose robust and accurate algorithms to create two- and three-dimensional
large FOV maps from cystoscopic video-sequences. Based on recent advances in the field of
discrete energy minimization, we propose transformation-invariant cost functions, which allow
to robustly register image pairs, related by large viewpoint changes, with sub-pixel accuracy.
The transformations linking such image pairs, which current state-of-the-art bladder image registration
techniques are unable to robustly estimate, are required to construct maps with several
overlapping image trajectories. We detect such overlapping trajectories automatically and perform
non-linear global map correction. Finally, the proposed energy minimization based map
compositing algorithm compensates small texture misalignments and attenuates strong exposure
differences. The obtained textured maps are composed by a maximum of information/quality
available from the redundant data of the video-sequence. We evaluate the proposed methods
both quantitatively and qualitatively on realistic phantom and clinical data sets. The results
demonstrate the robustness of the algorithms, and the obtained maps outperform state-of-theart
approaches in registration accuracy and global map coherence.

Keywords: 2D/3D Cartography, Bladder Cancer Diagnosis, Image Registration, Image Compositing,
Discrete Energy Minimization, Graph-Cuts.
Jury :
- Rapporteurs : Fabrice Heitz
Joachim Ohser
- Autres membres : François Guillemin, Jean-Marc Chassery, Ronald Rösch, Christian Daul, Didier Wolf