1 Introduction

The present data flow of many ongoing surveys - such as 2MASS (Beichman et al. 1998; Skrutskie 1999), DeNIS (Epchtein et al. 1997, 1999), EIS (Renzini & da Costa 1997; da Costa 1997; da Costa et al. 1998), OGLE-II (Udalski et al. 1997; Paczynski et al. 1999), SDSS (Fan 1999 and references cited therein), and even upcoming surveys as GAIA (Gilmore et al. 1998; Perryman et al. 2001) - is so large that one requires either a semi-automated or a fully automated method to analyse the colour-magnitude diagrams (CMDs) in the resulting databases. In this paper we discuss the development and the tests of an automated analysis method, which fully employs the colour and magnitude information available about the stars populating the CMD. Our method is based on an implementation of the CMD diagnostics suggested by Ng (1998). The method uses, in contrast to other techniques (see Bertelli et al. 1992; Gallart et al. 1996 & 1999; Geha et al. 1998 Harris & Zaritsky 2001; Hernandez et al. 1999; Holtzman et al. 1997 & 1999) the full, unbinned distribution of magnitudes and colours of the stars populating the CMD.

The purpose of this paper is to verify that astrophysical parameters for a synthetic single stellar population can be reliably retrieved with the so-called "AutoMatic Observation REnderer'' AMORE. In Sect. 2 an outline of AMORE is given together with its individual building blocks. In Sect. 3 we outline the method we use and in Sect. 4 we describe the tests performed with synthetic stellar populations. The results are given in Sect. 5 and we discuss in Sect. 6 the practical limits on the convergence, which is imposed by some degeneracy of the parameter space. We end with prospects on forthcoming tests, recommendations for improvements, and an outlook on future developments.