  Microtomography is a powerful method of materials investigation. It enables
to obtain physical properties of porous media non-destructively that is useful
in studies. One of the application ways is a calculation of porosity, pore
sizes, surface area, and other parameters of metal-ceramic (cermet) membranes
which are widely spread in the filtration industry. The microtomography
approach is efficient because all of those parameters are calculated
simultaneously in contrast to the conventional techniques. Nevertheless, the
calculations on Micro-CT reconstructed images appear to be time-consuming,
consequently representative volume element should be chosen to speed them up.
This research sheds light on representative elementary volume identification
without consideration of any physical parameters such as porosity, etc. Thus,
the volume element could be found even in noised and grayscale images. The
proposed method is flexible and does not overestimate the volume size in the
case of anisotropic samples. The obtained volume element could be used for
computations of the domain's physical characteristics if the image is filtered
and binarized, or for selections of optimal filtering parameters for denoising
procedure.
