Correlation method for quality control of master matrix used for embossing security holograms

摘要

Security holograms (SH) are widely used for authenticity protection of document and product due to difficulties of such a protection mark falsification. Mass production of SH uses widespread technology of hot foil or lavsan paper stamping. The quality of holograms significantly depends on perfection of nickel master-matrix that is used in stamping equipment. We represent the method for automated quality inspection of nickel master-matrix based on digital processing of its surface relief images. Proposed processing algorithm is based on combination of image spatial frequency analysis and image matching using distortion invariant correlation filters. The results of our method application for real master-matrix inspection are shown in this paper.