Apparatus for sensing optical characteristics of a banknote
AssigneeMars, Incorporated
InventorChristian Voser
Life of this patent
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Abstract
The optical characteristics of a banknote are measured by using first and second sets of optical devices positioned on respective sides of the banknote path. Each device includes a transmitter and an adjacent pair of receivers, the receivers being capable of receiving light from the adjacent transmitter which has been diffusively reflected by the banknote, and each receiver also receiving light from the transmitter of the opposed device. Calibration is carried out by moving a reference body of predetermined reflectance and transmittance characteristics into the banknote path between the devices.
Claims22
Apparatus for sensing optical characteristics of a banknote, the apparatus comprising at least a first optical receiver (6;7) and a first optical transmitter (4) on one side of a banknote path and a second optical transmitter (4′) on the other side of the banknote path, the first receiver (6;7) being arranged to sense (a) light transmitted via the banknote (2) from the second transmitter (4′) and (b) light transmitted from the first transmitter (4) and diffusely reflected by the banknote (2).
Apparatus as claimed in any preceding claim, including means for moving the banknote (2) in a scanning direction (S) in the plane (P1) of the banknote, to permit scanning of the banknote by the first receiver (6;7).
Apparatus for sensing optical characteristics of a banknote, the apparatus comprising at least a first optical transmitter (4) located on one side of a path along which a banknote (2) can be moved in a scanning direction (S) in the plane (P1) of the banknote for illuminating the banknote (2), and at least a first optical receiver (6;7) for receiving light diffusely reflected from the banknote, the first transmitter (4) being arranged to transmit light in a direction which is inclined with respect to the normal (N) to the plane (P1) of the banknote (2) and the first receiver (6;7) being arranged to receive light which is travelling in substantially the same path but the opposite direction from the light emitted by the transmitter (4).
Apparatus as claimed in any preceding claim, including a further optical receiver (9) arranged to sense light transmitted from the first transmitter (4) and specularly reflected by the banknote (2).
Apparatus as claimed in any preceding claim, wherein the first transmitter and the first receiver are mounted on a common circuit board.
Apparatus as claimed in any preceding claim, including a set of devices (3) each comprising a respective first receiver (6;7) and a respective first transmitter (4), each device (3) thereby being arranged to scan a respective area of one side of the banknote (2), the areas being displaced from each other in a direction (T) transverse to the scanning direction (S).
Apparatus for sensing optical characteristics of a banknote comprising a banknote path along which banknotes are arranged to travel, and means (4′,6) for transmitting light along a light path through a banknote in the banknote path to sense the optical transmission characteristics of the banknote, the apparatus further including a reference body (64) and means for moving the reference body between a first position located within the apparatus but out of the banknote path and a second position in said light path, and means for performing a calibration operation based on the output of at least one light sensor (6;7) when the reference body is in the second position.
Dependencies are inferred from the claim text.