Patent ID: 8577122

Claim:
A method for testing moving products ( 11 ) having at least two layers, wherein at least one layer ( 14 ) of the product ( 11 ), which is arranged further inwards, namely an inner layer, is covered at least regionally by at least one, at least partially transparent product layer ( 16 ), which is arranged further outwards, namely an outer layer, comprising the steps of: a) illuminating the outer layer ( 16 ) of the product ( 11 ) by unpolarized light, with light that is reflected at the outer layer ( 16 ) comprising at least 70% of linearly s-polarized light; b) the s-polarized component of the light reflected by the outer layer ( 16 ) and/or of light reflected by the inner layer ( 14 ) and/or a p-polarized component of the light reflected by the outer layer ( 16 ) and/or of the light reflected by the inner layer ( 14 ) is/are recorded in each case separately using at least one suitable electrooptic recording element ( 28 , 35 ) in the form of an image or partial image of the product ( 11 ), c) the recorded s-polarized and/or the recorded p-polarized light component is/are evaluated in order to be able to draw conclusions relating to features of the outer layer ( 16 ) and/or of the inner layer ( 14 ), wherein the outer layer ( 16 ) is part of a film wrap ( 12 ) of a cigarette package ( 13 ) and the inner layer ( 14 ) is part of the cigarette package ( 13 ), wherein the angle of incidence, under which the outer layer ( 16 ) is illuminated, is greater than 85% of the Brewster angle of the outer layer ( 16 ) and smaller than 115% of the Brewster angle of the outer layer ( 16 ), and approximately corresponds to the Brewster angle of the outer layer ( 16 ).