  I present in this paper a method to calibrate data obtained from optical and
infrared interferometers. I show that correlated noises and errors need to be
taken into account for a very good estimate of individual error bars but also
when model fitting the data to derive meaningful model parameters whose
accuracies are not overestimated. It is also shown that under conditions of
high correlated noise, faint structures of the source can be detected. This
point is important to define strategies of calibration for difficult programs
such as exoplanet detection. The limits of validity of the assumptions on the
noise statistics are discussed.
