Apparatus for sensing optical characteristics of a banknote
First Claim
1. 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;
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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 traveling in substantially the same path but the opposite direction from the light emitted by the transmitter (4) from a frame of reference in which the apparatus is viewed in a plane (P3) containing the scanning direction (S) and the normal (N) to the plane (P1) of the banknote (2).
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Accused Products
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.
100 Citations
16 Claims
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1. 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;
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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 traveling in substantially the same path but the opposite direction from the light emitted by the transmitter (4) from a frame of reference in which the apparatus is viewed in a plane (P3) containing the scanning direction (S) and the normal (N) to the plane (P1) of the banknote (2). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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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;
Specification