RECOGNITION OF FOREIGN OBJECTS ON OR IN BANKNOTES

摘要

The invention relates to a device and a corresponding method for recognizing foreign objects, particularly adhesive tape, on or in banknotes (1), comprising at least one unit (6) which irradiates a banknote (1) that is to be analyzed with electromagnetic rays (2), at least one detector (4) which detects the rays (3) reflected or transmitted by the banknote (1), and an evaluation unit (5) which recognizes foreign objects (10) located on or in the banknote (1) based on the detected rays (3). In order to increase reliability concerning the recognition of foreign objects, the wavelength of the rays (2, 3) lies within the medium infrared (MIR) spectrum, in which differences in the transmission behavior and reflection behavior between banknote areas (21) with and without adhesive tape (10) are clearly visible. Said differences are particularly great at wavelengths ranging between 5.5 and 6 ñm, especially between 5.7 and 5.8 ñm such that a high sensitivity to detection is obtained even for thin strips of adhesive tape.