  LOFAR is a new and innovative effort to build a radio-telescope operating at
the multi-meter wavelength spectral window. One of the most exciting
applications of LOFAR will be the search for redshifted 21-cm line emission
from the Epoch of Reionization (EoR). It is currently believed that the Dark
Ages, the period after recombination when the Universe turned neutral, lasted
until around the Universe was 400,000 years old. During the EoR, objects
started to form in the early universe and they were energetic enough to ionize
neutral hydrogen. The precision and accuracy required to achieve this
scientific goal, can be essentially translated into accumulating large amounts
of data. The data model describing the response of the LOFAR telescope to the
intensity distribution of the sky is characterized by the non-linearity of the
parameters and the large level of noise compared to the desired cosmological
signal. In this poster, we present the implementation of a statistically
optimal map-making process and its properties. The basic assumptions of this
method are that the noise is Gaussian and independent between the stations and
frequency channels and that the dynamic range of the data can been enhanced
significantly during the off-line LOFAR processing. These assumptions match our
expectations for the LOFAR Epoch of Reionization Experiment.
