Quality Inspection Of Security Holograms Considering The Influence Of Diffraction Grating Relief Distortions

Security holograms are widely used for authenticity protection of documents and products due to difficulties of such a protection mark falsification. The quality of holograms significantly depends on accordance of calculated and real phase relief parameters. We represent the method for automated quality inspection of security holograms. This method based on determining of phase relief parameters by registered results of the intensity distribution in diffraction orders. The profile of relief as a harmonious distribution is represented. Distortion of the ideal relief profile influence on the accuracy of this method. The mathematical expressions for evaluating the influence of the phase relief distortion on the intensity distribution in the diffraction orders are represented. Parameters of the correlation functions approximation describing the relief distortion are determined. The dependence of the intensity values on the standard deviation of the relief distortion is represented. The results of quality inspection for real security holograms are shown.