  Galactic archeology based on star counts is instrumental to reconstruct the
past mass assembly of Local Group galaxies. The development of new observing
techniques and data-reduction, coupled with the use of sensitive large field of
view cameras, now allows us to pursue this technique in more distant galaxies
exploiting their diffuse low surface brightness (LSB) light. As part of the
Atlas3D project, we have obtained with the MegaCam camera at the Canada-France
Hawaii Telescope extremely deep, multi--band, images of nearby early-type
galaxies. We present here a catalog of 92 galaxies from the Atlas3D sample,
that are located in low to medium density environments. The observing strategy
and data reduction pipeline, that achieve a gain of several magnitudes in the
limiting surface brightness with respect to classical imaging surveys, are
presented. The size and depth of the survey is compared to other recent deep
imaging projects. The paper highlights the capability of LSB--optimized surveys
at detecting new prominent structures that change the apparent morphology of
galaxies. The intrinsic limitations of deep imaging observations are also
discussed, among those, the contamination of the stellar halos of galaxies by
extended ghost reflections, and the cirrus emission from Galactic dust. The
detection and systematic census of fine structures that trace the present and
past mass assembly of ETGs is one of the prime goals of the project. We provide
specific examples of each type of observed structures -- tidal tails, stellar
streams and shells --, and explain how they were identified and classified. We
give an overview of the initial results. The detailed statistical analysis will
be presented in future papers.
