Printing security documents (eg banknotes) with invisible features having a pattern detectable by computer

摘要

Security documents such as a banknotes, are encoded with printed identification features which are invisible to the eye but which are repeated over of the surface of the document substrate to enable detection, after scanning, by a computer to authorise the document or to prevent its replication. The features may be arranged in a 2D matrix and be spaced at regular intervals over the substrate. Additional physical features may be formed by embossing, surface treatment of lacquered papers, impregnation, laser treatment or watermarking. The features enable banknote authentification and determination of denomination.