  A multifractal analysis is performed on a three-dimensional grayscale image
associated with a complex system. First, a procedure for generating 3D
synthetic images (2D image stacks) of a complex structure exhibiting
multifractal behaviour is described. Then, in order to characterize the 3D
system, the theoretical calculation of the generalized fractal dimension and
two different approaches for evaluating the singularity spectrum are presented.
