  Post-AGB stars are key objects for the study of the dramatic morphological
changes of low- to intermediate-mass stars on their evolution from the
Asymptotic Giant Branch (AGB) towards the Planetary Nebula stage. There is
growing evidences that binary interaction processes may very well have a
determining role in the shaping process of many objects, but so far direct
evidence is still weak. We aim at a systematic study of the dust distribution
around a large sample of Post-AGB stars as a probe of the symmetry breaking in
the nebulae around these systems. We used imaging in the mid-infrared to study
the inner part of these evolved stars to probe direct emission from dusty
structures in the core of Post-AGB stars in order to better understand their
shaping mechanisms. We imaged a sample of 93 evolved stars and nebulae in the
mid-infrared using VISIR/VLT, T-Recs/Gemini South and Michelle/Gemini North. We
found that all the the Proto-Planetary Nebulae we resolved show a clear
departure from spherical symmetry. 59 out of the 93 observed targets appear to
be non resolved. The resolved targets can be divided in two categories. The
nebulae with a dense central core, that are either bipolar and multipolar. The
nebulae with no central core have an elliptical morphology.The dense central
torus observed likely host binary systems which triggered fast outflows that
shaped the nebulae.
