Bonjour à tous,
J'ai le plaisir de vous inviter à la soutenance de ma thèse intitulée
``Prise en compte d'informations d'inclusion et d'adjacence dans les
représentations morphologiques hiérarchiques, avec application à
l'extraction de texte en images naturelles et vidéos.’’
Celle-ci aura lieu le jeudi 13 décembre 2018 à 10h00 en salle KB 604 à
l'EPITA
La soutenance sera suivie d'un pot.
https://www.lrde.epita.fr/wiki/Affiche-these-DH
Manuscrit de thèse
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https://1drv.ms/b/s!AmbdUYjEYP52i8BOYRqHLImi0oykfQ
Composition du jury de thèse
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Rapporteurs :
Beatriz MARCOTEGUI, Pr., MINES ParisTech, CMM
Hugues TALBOT, Pr., CentraleSupelec, CVC
Examinateurs :
Isabelle BLOCH, Pr., Telecom ParisTech, LTCI
Laurent NAJMAN , Pr., l'Université Paris-Est, LIGM
Camille KURTZ, MdC, Université Paris Descartes, LIPADE
Directeurs de thèse :
Thierry GÉRAUD, Pr., EPITA, LRDE
Yongchao XU, MdC, HUST, Chine, MCLab
Résumé de la thèse
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With the rising need for a higher understanding of images, the
pixel-based representation is not enough. To answer this, the
mathematical morphology framework provides several multi-scale,
region-based image representations which include the hierarchies of
segmentation (e.g., alpha-tree, BPT) and trees based on the threshold
decomposition (Min/Max-trees and Tree of Shapes). Because objects in the
real world rarely appear in isolation but a typical context with other
related objects, we should consider the spatial relationships between
image regions.
We are interested in two type of relationship, namely the inclusion and
adjacency (in the sense of ``being nearby) since they usually carry
contextual information. The adjacency between regions gives us a sense
of how regions are arranged in images and have been widely used. On the
other hand, while fitting the human's perception of the
object-background relationship: the objects are included in their
background, the inclusion relationship is usually not taken into
account. Both these drastic information opens up possibilities for image
analysis. In this thesis, we take advantage of both inclusion and
adjacency information in morphological hierarchical representations for
computer vision applications.
We introduce the spatial alignment graph w.r.t inclusion (SAG) that is
constructed from both inclusion and spatial arrangement of regions in
the tree-based image representations.
For simple scenes, we introduce the Tree of Shapes of Laplacian sign. It
encodes the inclusion of 0-crossing of a Morphological Laplacian map and
performs well even in the case of uneven illumination. The ToSoL is
computed in linear time w.r.t the number of pixels thanks to an
optimization that mimics well-composedness. In this representation, the
spatial alignment graph is reduced to a disconnected graph where each
connected component is a semantic group of objects.
For higher detail representation, the spatial alignment graph becomes
more complex. To address this issue, we expand the idea of the shape
spaces morphology. Our expansion has two primary results: 1) It allows
the manipulation of any graph of shapes that encode different
information, which encompasses the SAG. 2) It allows any tree filtering
strategy proposed by the connected operators frameworks. Within this
expansion, the SAG could be analyzed with an alpha-tree.
We demonstrated the application aspect of our method in text detection.
The experiment results show the efficiency and effectiveness of our
methods, which robust to noise, blur, or uneven illumination. These
features are appealing to mobile applications.