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Adrien Krähenbühl

Associate professor × IUT Robert Schuman × ICube × Unistra

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2014 - Ph.D. thesis (Regional Thesis Award 2015)

Segmentation and geometric analysis: application to CT images of wood

Defended on December 12, 2014, at LORIA.
Awarded the Regional Thesis Prize 2015 in scientific sector (Region/LORIA/INRA statements).

Jury members

    Michel Couprie   Professor, ESIEE, Université Paris-Est
    Achille Braquelaire   Professor, LaBRI, Université de Bordeaux
    Franka Brüchert   Professor, FVA, Baden-Württemberg, Freiburg
    Fabien Feschet   Professor, ISIT, Université d'Auvergne
    Fleur Longuetaud   Senior researcher, INRA, Champenoux
    Frédéric Mothe   Senior researcher, INRA, Champenoux
    Isabelle Debled   Professor, LORIA, Université de Lorraine
    Bertrand Kerautret   Associate professor, LORIA, Univ. de Lorraine


Schema trunk parts. The non-destructive study of wood from X-Ray CT scanners requires to imagine new solutions adapted to analysis of images. Relating both agronomic research and industrial sector of sawmills, segmentation of wood knots is a major challenge in terms of robustness to specificities of each species and to image acquisition conditions. The works carried out in this thesis allow to propose a segmentation process in two phases. It first isolates each knot in a reduced area then it segments the unique knot of each area. Proposed solutions for each phase allow to integrate knowledges about internal organization of trunk and mechanisms inherent to its growth, through classical tools of image analysis and processing. The first phase is essentially based on a movement detection principle borrowed from video analysis and revisited. 3D reconstruction of trunk with segmented knots. Two segmentation approaches are then proposed, considering for one the initial CT slices and for the other news slices resampled for each knot orthogonally to its trajectory. The complete process has been implemented in a software dedicated both for experimentation and validation of approach, and to interdisciplinary dialogs.

The applicative support of wood emphasizes the specialization abilities of generic image analysis and processing algorithms, and the relevance to integrate priori knowledges in this perspective.

Keywords: segmentation, CT images, geometric analysis, discrete geometry, wood knots.

Thesis document:      Defense slides:  

2011 - Master’s thesis (2nd year)

Search by fine visual similarity in digitized photographic collections


2010 - Master’s degree (1st year)

Detection and geometrical measurements of wood knots in spruce logs

Co-supervised by [Isabelle Debled-Rennesson] and Bertrand Kerautret.
In collaboration with Fleur Longuetaud and Frédéric Mothe from INRA.


2009 - Bachelor's degree (3rd year)

MoProViewer: Molecular visualization software

Supervised by Benoit Guillot.
In the CRM² lab, "Cristallographie, Résonance Magnétique et Modélisations".
In pairs with Laurent Hory.


2008 - Bachelor's degree (2nd year)

Database, XML and mailing lists

Supervised by Olivier Martzloff.
At Edition service of the Lorraine CRDP (Centre Régional de Documentation Pédagogique).