  Finite detector resolution and limited acceptance require to apply unfolding
methods in high energy physics experiments. Information on the detector
resolution is usually given by a set of Monte Carlo events. Based on the
experience with a widely used unfolding program (RUN) a modified method has
been developed.
  The first step of the method is a maximum likelihood fit of the Monte Carlo
distributions to the measured distribution in one, two or three dimensions; the
finite statistic of the Monte Carlo events is taken into account by the use of
Barlows method with a new method of solution. A clustering method is used
before to combine bins in sparsely populated areas. In the second step a
regularization is applied to the solution, which introduces only a small bias.
The regularization parameter is determined from the data after a
diagonalization and rotation procedure.
