| 摘要 |
PCT No. PCT/FI89/00043 Sec. 371 Date Oct. 30, 1990 Sec. 102(e) Date Oct. 30, 1990 PCT Filed Mar. 10, 1989 PCT Pub. No. WO89/08898 PCT Pub. Date Sep. 21, 1989.A method and a device for automatic verification of genuineness of a banknote or a document comprising a watermark is described. A two-part, doubly active capacitive sensor device (4, 6, 7) is used. A symmetry property of the sensor output signal is changed in a predetermined manner when a correct watermark is present in a coinciding position with shape-adapted capacitor electrodes (4, 6).
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