2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/6801We present inversion techniques aiming at recovering the stellar content (age, metallicity, extinction) and kinematics of a stellar population from its absorption line spectrum. These techniques use new synthetic high resolution spectra produced by PEGASE_HR and minimization algorithms. Application to SDSS data and to a simulated disc-bulge system are presented as examples.2 pages, 2 figures, poster presented at SF2A 2003 conference in BordeauxAstrophysicstext