  Bragg interferometry (BI) is an imaging technique based on four-dimensional
scanning electron microscopy (4D-STEM) wherein the intensities of select
overlapping Bragg disks are fit or more qualitatively analyzed in the context
of simple trigonometric equations to determine local stacking order. In 4D-STEM
based approaches, the collection of full diffraction patterns at each
real-space position of the scanning probe allows the use of precise virtual
apertures much smaller and more variable in shape than those used in
conventional dark field imaging, such that even buried interfaces marginally
twisted from other layers can be targeted. A coarse-grained form of dark field
ptychography, BI uses simple physically derived fitting functions to extract
the average structure within the illumination region and is therefore viable
over large fields of view. BI has shown a particular advantage for selectively
investigating the interlayer stacking and associated moir\'e reconstruction of
bilayer interfaces within complex multi-layered structures. This has enabled
investigation of reconstruction and substrate effects in bilayers through
encapsulating hexagonal boron nitride and of select bilayer interfaces within
trilayer stacks. However, the technique can be improved to provide a greater
spatial resolution and probe a wider range of twisted structures, for which
current limitations on acquisition parameters can lead to large illumination
regions and the computationally involved post-processing can fail. Here we
analyze these limitations and the computational processing in greater depth,
presenting a few methods for improvement over previous works, discussing
potential areas for further expansion, and illustrating the current
capabilities of this approach for extracting moir\'e-scale strain.
