PROCEDE DE TEST VISUEL D'OPACITE DE PAVES GRATTABLES ET DISPOSITIF DE MISE EN OEUVRE

摘要

The invention concerns a method and a device for visually testing the opacity of scratch-off tiles (6) masking an information inscribed on the medium (5). The invention is characterised in that the method consists in successively illuminating the scratch-off tile using optical rays pertaining to sub-bands of the visible spectrum wavelength band. The invention is particularly applicable to smart cards.