2000A&AS..142..339B

The observing material used for this task is prism spectral plates taken with Schmidt-class telescopes. Such a plate generally contains thousands of spectra, and there are prism-plate libraries and digitized databases in several astronomical centers that can be exploited for this analysis. After a successive detection from the prism plate image, the spectra are automaticaly extracted in one-dimensional streams containing all the basic information. These spectra require automated classification methods to be analyzed in an objective form. In this article we compare two classification methods directly applied to stellar spectra: a linear correlation and a minimum distance method.