  Microscale imaging of mesoscale bulk materials under dynamic compression is
important for understanding their properties. In this work, we study the
effects of the depth of field (DoF) and field of view (FoV) of the optical lens
and extract the scattered light of the region to be imaged within the bulk
polycrystalline material based on the objective Bragg coherent diffraction
imaging. We describe how the DoF and FoV quantitatively limit the diffraction
volume, where the DoF and FoV limit the scattering region parallel and
perpendicular to the direction of the light source respectively. We demonstrate
this scheme by simulating the separate imaging of a submicron-sized crack
region within a few {\mu}m-sized Si bulk material, and obtain a high imaging
quality. This scheme enables imaging of selected regions within bulk
polycrystalline materials with the resolution up to the order of 10 nm.
