  Limited-angle tomography is a highly ill-posed linear inverse problem. It
arises in many applications, such as digital breast tomosynthesis.
Reconstructions from limited-angle data typically suffer from severe stretching
of features along the central direction of projections, leading to poor
separation between slices perpendicular to the central direction. A new method
is introduced, based on machine learning and geometry, producing an estimate
for interfaces between regions of different X-ray attenuation. The estimate can
be presented on top of the reconstruction, indicating more reliably the true
form and extent of features. The method uses directional edge detection,
implemented using complex wavelets and enhanced with morphological operations.
By using machine learning, the visible part of the wavefront set is first
extracted and then extended to the full domain, filling in the parts of the
wavefront set that would otherwise be hidden due to the lack of measurement
directions.
