  The problem of restoration of the source brightness distribution from an
analysis of the stellar and AGNs microlensing light curves is investigated. In
case of microlensing of stars by a point-mass lens as well as for caustic
crossing events for binary lens the problem can be reduced to solution of the
Fredholm integral equation of the 1st kind. Concrete form of the kernel of this
equation depends on a type of the microlensing event. Assuming the circular
symmetry of the stellar disk the search for radial brightness distribution can
be carried out in the special compact sets of functions which correspond to the
physics of the problem. These sets include the non-negative functions that are
not increasing with increasing distance from the center of stellar disk and the
upwards convex non-negative functions. The brightness distribution for the AGNs
accretion disks is also circularly symmetric, but only in the locally co-moving
frame. Therefore, the kernel of integral equation that determined the AGN
microlensing light curve must take into account equally with the projection
effect on picture plane the influence of relativistic effects. The search for
solution of this equation can be carried out in the set of non-negative down
convex functions. The results of analysis of microlensing light curves for the
red giant MACHO Alert 95-30 and the A6 star MACHO 98-SMC-1 as well as the
results of numerical simulations for the AGN microlensing observations are
given.
