  This research report summarizes the progress of work carried out jointly by
the IRCCyN and the \'Ecole Polytechnique de Montr\'eal about the resolution of
the inverse problem for the seismic imaging of transmission overhead line
structure foundations. Several methods aimed at mapping the underground medium
are considered. More particularly, we focus on methods based on a bilinear
formulation of the forward problem on one hand (CSI, modified gradient, etc.)
and on methods based on a "primal" formulation on the other hand. The
performances of these methods are compared using synthetic data. This work was
partially funded by RTE (R\'eseau de Transport d'\'Electricit\'e), which has
initiated the project, and was carried out in collaboration with EDF R&D
(\'Electricit\'e de France - Recherche et D\'eveloppement).
