Scanning electron microscopy (SEM) is widely used in surface studies
and continuous efforts are carried out in the search of estimators of
different surface characteristics. By using the variogram, we developed
two of these estimators that were used to characterize the surface
roughness from the SEM image texture. One of the estimators is related to
the crossover between fractal region at low scale and the periodic region
at high scale, whereas the other estimator characterizes the periodic
region. In this work, a full study of these estimators and the fractal
dimension in two dimensions (2D) and three dimensions (3D) was carried out
for emery papers. We show that the obtained fractal dimension with only
one image is good enough to characterize the roughness surface because its
behavior is similar to those obtained with 3D height data. We show also
that the estimator that indicates the crossover is related to the minimum
cell size in 2D and to the average particle size in 3D. The other
estimator has different values for the three studied emery papers in 2D
but it does not have a clear meaning, and these values are similar for
those studied samples in 3D. Nevertheless, it indicates the formation
tendency of compound cells. The fractal dimension values from the
variogram and from an area versus step log–log graph were studied
with 3D data. Both methods yield different values corresponding to
different information from the samples.