  We propose a method to reconstruct the 3-D molecular structure from
micrographs collected at just one sample tilt angle in the random conical tilt
scheme in cryo-electron microscopy. Our method uses autocorrelation analysis on
the micrographs to estimate features of the molecule which are invariant under
certain nuisance parameters such as the positions of molecular projections in
the micrographs. This enables us to reconstruct the molecular structure
directly from micrographs, completely circumventing the need for particle
picking. We demonstrate reconstructions with simulated data and investigate the
effect of the missing-cone region. These results show promise to reduce the
size limit for single particle reconstruction in cryo-electron microscopy.
