  The purpose of this paper is to present a method to self-calibrate the
spectral energy distribution (SED) of objects in a survey based on the fitting
of an SED library to the observed multi-color photometry. We adopt for
illustrative purposes the Vilnius (Strizyz and Sviderskiene 1972) and Gunn &
Stryker (1983) SED libraries. The self-calibration technique can improve the
quality of observations which are not taken under perfectly photometric
conditions. The more passbands used for the photometry, the better the results.
This technique has been applied to the BATC 15-passband CCD survey.
