Method for checking authenticity of a hologram and a reading device for the performance of the method

摘要

A method for determining the authenticity of a hologram with the following steps: a) The hologram (1) to be checked is illuminated with a restoration ray (2): b) The diffraction ray (3) of the first order of the wave field created at the hologram is imaged on a first photo-sensitive element, in particular a CCD target (5), and brought to interference with a first reference ray (7); c) The diffraction ray (4) of the zeroth order of the wave field created at the hologram (1) is imaged on a second photo-sensitive element, in particular a CCD target (6) and brought to interference with a second reference ray (10); d) The intensity distributions created at the different photo-sensitive elements (5, 6) are correlated with each other for at least two phase relationships between the restoration ray (2) and the different reference rays (7, 10) to obtain a correlation intensity distribution for the relevant orders of diffraction; and e) The correlation intensity distributions determined for the relevant orders of diffraction are correlated with each other, particularly subtracted from each other pixel by pixel.