METHOD OF TEST OF AUTHENTICITY OF MONEY AND SURETY DOCUMENTS AND DEVICE FOR ITS IMPLEMENTATION (VERSIONS) Russian patent published in 1997 - IPC

FIELD: money and surety documents of rectangular form carrying printed graphic image and protective signs, specifically, banknotes. SUBSTANCE: specific feature of documents used in invention lies in manufacture of first protection sign in the form of periodic net of parallel lines of water marks arranged at certain angle β to first (long) edge of document and in application of it on to second protective sign produced in the form of stripes of printed graphic image of same width parallel to first edge of document. Reaction of at least one of paints of this image for pairs of symmetric stripes different relative to middle of second edge of document to electromagnetic radiation of specified range of wave lengths (for example, to infrared radiation) is different. Thanks to it coding of these stripes in symmetry with reference to middle of second edge of document is provided. While testing document is moved by radiation sensors placed perpendicular top direction of movement coinciding with first edge of document. If angle β is less than right angle then sensors are arranged in row, if angle β is equal to right angle then sensors are divided into two groups with regard to middle of second edge of document and one group is displaced relative to the other in direction of movement of document by half-length of wave of wave-like relief of water marks in section of first protective sign perpendicular to direction of its parallel lines. Signals of sensors are subjected in both cases to proper processing to extract signal corresponding to this wave-like relief of water marks. EFFECT: improved efficiency and reliability of method and device. 16 cl, 21 dwg